snapshot of https://github.com/seaweedfs/seaweedfs.git (master, 2026-09-16; blobs > 131072B omitted)

other/java/hdfs3/README.md

@@ -0,0 +1,199 @@
+# SeaweedFS Hadoop3 Client
+
+Hadoop FileSystem implementation for SeaweedFS, compatible with Hadoop 3.x.
+
+## Building
+
+```bash
+mvn clean install
+```
+
+## Testing
+
+This project includes two types of tests:
+
+### 1. Configuration Tests (No SeaweedFS Required)
+
+These tests verify configuration handling and initialization logic without requiring a running SeaweedFS instance:
+
+```bash
+mvn test -Dtest=SeaweedFileSystemConfigTest
+```
+
+### 2. Integration Tests (Requires SeaweedFS)
+
+These tests verify actual FileSystem operations against a running SeaweedFS instance.
+
+#### Prerequisites
+
+1. Start SeaweedFS with default ports:
+   ```bash
+   # Terminal 1: Start master
+   weed master
+   
+   # Terminal 2: Start volume server
+   weed volume -master=localhost:9333
+   
+   # Terminal 3: Start filer
+   weed filer -master=localhost:9333
+   ```
+
+2. Verify services are running:
+   - Master: http://localhost:9333
+   - Filer HTTP: http://localhost:8888
+   - Filer gRPC: localhost:18888
+
+#### Running Integration Tests
+
+```bash
+# Enable integration tests
+export SEAWEEDFS_TEST_ENABLED=true
+
+# Run all tests
+mvn test
+
+# Run specific test
+mvn test -Dtest=SeaweedFileSystemTest
+```
+
+### Test Configuration
+
+Integration tests can be configured via environment variables or system properties:
+
+- `SEAWEEDFS_TEST_ENABLED`: Set to `true` to enable integration tests (default: false)
+- Tests use these default connection settings:
+  - Filer Host: localhost
+  - Filer HTTP Port: 8888
+  - Filer gRPC Port: 18888
+
+### Running Tests with Custom Configuration
+
+To test against a different SeaweedFS instance, modify the test code or use Hadoop configuration:
+
+```java
+conf.set("fs.seaweed.filer.host", "your-host");
+conf.setInt("fs.seaweed.filer.port", 8888);
+conf.setInt("fs.seaweed.filer.port.grpc", 18888);
+```
+
+## Test Coverage
+
+The test suite covers:
+
+- **Configuration & Initialization**
+  - URI parsing and configuration
+  - Default values
+  - Configuration overrides
+  - Working directory management
+
+- **File Operations**
+  - Create files
+  - Read files
+  - Write files
+  - Append to files
+  - Delete files
+
+- **Directory Operations**
+  - Create directories
+  - List directory contents
+  - Delete directories (recursive and non-recursive)
+
+- **Metadata Operations**
+  - Get file status
+  - Set permissions
+  - Set owner/group
+  - Rename files and directories
+
+## Usage in Hadoop
+
+1. Copy the built JAR to your Hadoop classpath:
+   ```bash
+   cp target/seaweedfs-hadoop3-client-*.jar $HADOOP_HOME/share/hadoop/common/lib/
+   ```
+
+2. Configure `core-site.xml`:
+   ```xml
+   <configuration>
+     <property>
+       <name>fs.seaweedfs.impl</name>
+       <value>seaweed.hdfs.SeaweedFileSystem</value>
+     </property>
+     <property>
+       <name>fs.seaweed.filer.host</name>
+       <value>localhost</value>
+     </property>
+     <property>
+       <name>fs.seaweed.filer.port</name>
+       <value>8888</value>
+     </property>
+     <property>
+       <name>fs.seaweed.filer.port.grpc</name>
+       <value>18888</value>
+     </property>
+     <!-- Optional: Replication configuration with three priority levels:
+          1) If set to non-empty value (e.g. "001") - uses that value
+          2) If set to empty string "" - uses SeaweedFS filer's default replication
+          3) If not configured (property not present) - uses HDFS replication parameter
+     -->
+     <!-- <property>
+       <name>fs.seaweed.replication</name>
+       <value>001</value>
+     </property> -->
+   </configuration>
+   ```
+
+3. Use SeaweedFS with Hadoop commands:
+   ```bash
+   hadoop fs -ls seaweedfs://localhost:8888/
+   hadoop fs -mkdir seaweedfs://localhost:8888/test
+   hadoop fs -put local.txt seaweedfs://localhost:8888/test/
+   ```
+
+## Continuous Integration
+
+For CI environments, tests can be run in two modes:
+
+1. **Configuration Tests Only** (default, no SeaweedFS required):
+   ```bash
+   mvn test -Dtest=SeaweedFileSystemConfigTest
+   ```
+
+2. **Full Integration Tests** (requires SeaweedFS):
+   ```bash
+   # Start SeaweedFS in CI environment
+   # Then run:
+   export SEAWEEDFS_TEST_ENABLED=true
+   mvn test
+   ```
+
+## Troubleshooting
+
+### Tests are skipped
+
+If you see "Skipping test - SEAWEEDFS_TEST_ENABLED not set":
+```bash
+export SEAWEEDFS_TEST_ENABLED=true
+```
+
+### Connection refused errors
+
+Ensure SeaweedFS is running and accessible:
+```bash
+curl http://localhost:8888/
+```
+
+### gRPC errors
+
+Verify the gRPC port is accessible:
+```bash
+# Should show the port is listening
+netstat -an | grep 18888
+```
+
+## Contributing
+
+When adding new features, please include:
+1. Configuration tests (no SeaweedFS required)
+2. Integration tests (with SEAWEEDFS_TEST_ENABLED guard)
+3. Documentation updates
+

other/java/hdfs3/dependency-reduced-pom.xml

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+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
+  <modelVersion>4.0.0</modelVersion>
+  <groupId>com.seaweedfs</groupId>
+  <artifactId>seaweedfs-hadoop3-client</artifactId>
+  <name>SeaweedFS HDFS3 Client</name>
+  <version>${seaweedfs.client.version}</version>
+  <description>A java client for SeaweedFS.</description>
+  <url>https://github.com/seaweedfs/seaweedfs</url>
+  <developers>
+    <developer>
+      <name>Chris Lu</name>
+      <email>chris.lu@gmail.com</email>
+      <organization>SeaweedFS</organization>
+      <organizationUrl>https://seaweedfs.com</organizationUrl>
+    </developer>
+  </developers>
+  <licenses>
+    <license>
+      <name>The Apache License, Version 2.0</name>
+      <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
+    </license>
+  </licenses>
+  <scm>
+    <connection>scm:git:git://github.com/seaweedfs/seaweedfs.git</connection>
+    <developerConnection>scm:git:ssh://github.com:seaweedfs/seaweedfs.git</developerConnection>
+    <url>https://github.com/seaweedfs/seaweedfs/tree/master</url>
+  </scm>
+  <build>
+    <plugins>
+      <plugin>
+        <artifactId>maven-compiler-plugin</artifactId>
+        <configuration>
+          <source>8</source>
+          <target>8</target>
+          <release>8</release>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-shade-plugin</artifactId>
+        <version>3.2.1</version>
+        <executions>
+          <execution>
+            <phase>package</phase>
+            <goals>
+              <goal>shade</goal>
+            </goals>
+            <configuration>
+              <filters>
+                <filter>
+                  <artifact>*:*</artifact>
+                  <excludes>
+                    <exclude>META-INF/*.SF</exclude>
+                    <exclude>META-INF/*.DSA</exclude>
+                    <exclude>META-INF/*.RSA</exclude>
+                    <exclude>org/slf4j/**</exclude>
+                    <exclude>META-INF/maven/org.slf4j/**</exclude>
+                  </excludes>
+                </filter>
+              </filters>
+              <transformers>
+                <transformer />
+              </transformers>
+              <relocations>
+                <relocation>
+                  <pattern>com.google</pattern>
+                  <shadedPattern>shaded.com.google</shadedPattern>
+                </relocation>
+                <relocation>
+                  <pattern>io.grpc.internal</pattern>
+                  <shadedPattern>shaded.io.grpc.internal</shadedPattern>
+                </relocation>
+                <relocation>
+                  <pattern>org.apache.commons</pattern>
+                  <shadedPattern>shaded.org.apache.commons</shadedPattern>
+                  <excludes>
+                    <exclude>org.apache.hadoop</exclude>
+                    <exclude>org.apache.log4j</exclude>
+                  </excludes>
+                </relocation>
+                <relocation>
+                  <pattern>org.apache.http</pattern>
+                  <shadedPattern>shaded.org.apache.http</shadedPattern>
+                </relocation>
+              </relocations>
+            </configuration>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <artifactId>maven-gpg-plugin</artifactId>
+        <version>1.5</version>
+        <executions>
+          <execution>
+            <id>sign-artifacts</id>
+            <phase>verify</phase>
+            <goals>
+              <goal>sign</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <groupId>org.sonatype.central</groupId>
+        <artifactId>central-publishing-maven-plugin</artifactId>
+        <version>0.5.0</version>
+        <extensions>true</extensions>
+        <configuration>
+          <publishingServerId>central</publishingServerId>
+          <autoPublish>true</autoPublish>
+        </configuration>
+      </plugin>
+      <plugin>
+        <artifactId>maven-source-plugin</artifactId>
+        <version>2.2.1</version>
+        <executions>
+          <execution>
+            <id>attach-sources</id>
+            <goals>
+              <goal>jar-no-fork</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+      <plugin>
+        <artifactId>maven-javadoc-plugin</artifactId>
+        <version>3.0.1</version>
+        <executions>
+          <execution>
+            <id>attach-javadocs</id>
+            <goals>
+              <goal>jar</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+    </plugins>
+  </build>
+  <dependencies>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-client</artifactId>
+      <version>3.4.0</version>
+      <scope>provided</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>hadoop-hdfs-client</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-yarn-api</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-yarn-client</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-mapreduce-client-core</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-mapreduce-client-jobclient</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-annotations</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-common</artifactId>
+      <version>3.4.0</version>
+      <scope>provided</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>hadoop-shaded-protobuf_3_21</artifactId>
+          <groupId>org.apache.hadoop.thirdparty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-shaded-guava</artifactId>
+          <groupId>org.apache.hadoop.thirdparty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-cli</artifactId>
+          <groupId>commons-cli</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-math3</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-io</artifactId>
+          <groupId>commons-io</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-net</artifactId>
+          <groupId>commons-net</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-collections</artifactId>
+          <groupId>commons-collections</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>javax.servlet-api</artifactId>
+          <groupId>javax.servlet</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jakarta.activation-api</artifactId>
+          <groupId>jakarta.activation</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jetty-server</artifactId>
+          <groupId>org.eclipse.jetty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jetty-util</artifactId>
+          <groupId>org.eclipse.jetty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jetty-servlet</artifactId>
+          <groupId>org.eclipse.jetty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jetty-webapp</artifactId>
+          <groupId>org.eclipse.jetty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jsp-api</artifactId>
+          <groupId>javax.servlet.jsp</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jersey-core</artifactId>
+          <groupId>com.sun.jersey</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jersey-servlet</artifactId>
+          <groupId>com.sun.jersey</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jersey-json</artifactId>
+          <groupId>com.github.pjfanning</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jettison</artifactId>
+          <groupId>org.codehaus.jettison</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jersey-server</artifactId>
+          <groupId>com.sun.jersey</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>reload4j</artifactId>
+          <groupId>ch.qos.reload4j</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-beanutils</artifactId>
+          <groupId>commons-beanutils</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-configuration2</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-lang3</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-text</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>slf4j-reload4j</artifactId>
+          <groupId>org.slf4j</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>avro</artifactId>
+          <groupId>org.apache.avro</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>re2j</artifactId>
+          <groupId>com.google.re2j</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-auth</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jsch</artifactId>
+          <groupId>com.jcraft</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>curator-client</artifactId>
+          <groupId>org.apache.curator</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>curator-recipes</artifactId>
+          <groupId>org.apache.curator</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>zookeeper</artifactId>
+          <groupId>org.apache.zookeeper</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>netty-handler</artifactId>
+          <groupId>io.netty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>netty-transport-native-epoll</artifactId>
+          <groupId>io.netty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>metrics-core</artifactId>
+          <groupId>io.dropwizard.metrics</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-compress</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>bcprov-jdk15on</artifactId>
+          <groupId>org.bouncycastle</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>kerb-core</artifactId>
+          <groupId>org.apache.kerby</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jackson-databind</artifactId>
+          <groupId>com.fasterxml.jackson.core</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>stax2-api</artifactId>
+          <groupId>org.codehaus.woodstox</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>woodstox-core</artifactId>
+          <groupId>com.fasterxml.woodstox</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>dnsjava</artifactId>
+          <groupId>dnsjava</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>snappy-java</artifactId>
+          <groupId>org.xerial.snappy</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-annotations</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>junit</groupId>
+      <artifactId>junit</artifactId>
+      <version>4.13.1</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>hamcrest-core</artifactId>
+          <groupId>org.hamcrest</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>org.mockito</groupId>
+      <artifactId>mockito-core</artifactId>
+      <version>3.12.4</version>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>byte-buddy</artifactId>
+          <groupId>net.bytebuddy</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>byte-buddy-agent</artifactId>
+          <groupId>net.bytebuddy</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>objenesis</artifactId>
+          <groupId>org.objenesis</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+    <dependency>
+      <groupId>org.apache.hadoop</groupId>
+      <artifactId>hadoop-common</artifactId>
+      <version>3.4.0</version>
+      <type>test-jar</type>
+      <scope>test</scope>
+      <exclusions>
+        <exclusion>
+          <artifactId>hadoop-shaded-protobuf_3_21</artifactId>
+          <groupId>org.apache.hadoop.thirdparty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-shaded-guava</artifactId>
+          <groupId>org.apache.hadoop.thirdparty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-cli</artifactId>
+          <groupId>commons-cli</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-math3</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-io</artifactId>
+          <groupId>commons-io</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-net</artifactId>
+          <groupId>commons-net</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-collections</artifactId>
+          <groupId>commons-collections</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>javax.servlet-api</artifactId>
+          <groupId>javax.servlet</groupId>
+        </exclusion>
+        <exclusion>
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+          <groupId>jakarta.activation</groupId>
+        </exclusion>
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+        </exclusion>
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+        </exclusion>
+        <exclusion>
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+        </exclusion>
+        <exclusion>
+          <artifactId>jetty-webapp</artifactId>
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+        </exclusion>
+        <exclusion>
+          <artifactId>jsp-api</artifactId>
+          <groupId>javax.servlet.jsp</groupId>
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+        </exclusion>
+        <exclusion>
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+        </exclusion>
+        <exclusion>
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+        <exclusion>
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+          <groupId>ch.qos.reload4j</groupId>
+        </exclusion>
+        <exclusion>
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+          <groupId>commons-beanutils</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-configuration2</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-lang3</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>commons-text</artifactId>
+          <groupId>org.apache.commons</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>slf4j-reload4j</artifactId>
+          <groupId>org.slf4j</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>avro</artifactId>
+          <groupId>org.apache.avro</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>re2j</artifactId>
+          <groupId>com.google.re2j</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-auth</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+        <exclusion>
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+          <groupId>com.jcraft</groupId>
+        </exclusion>
+        <exclusion>
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+          <groupId>org.apache.curator</groupId>
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+        <exclusion>
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+          <groupId>org.apache.curator</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>zookeeper</artifactId>
+          <groupId>org.apache.zookeeper</groupId>
+        </exclusion>
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+          <groupId>io.netty</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>netty-transport-native-epoll</artifactId>
+          <groupId>io.netty</groupId>
+        </exclusion>
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+          <groupId>io.dropwizard.metrics</groupId>
+        </exclusion>
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+          <groupId>org.apache.commons</groupId>
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+        <exclusion>
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+        <exclusion>
+          <artifactId>kerb-core</artifactId>
+          <groupId>org.apache.kerby</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>jackson-databind</artifactId>
+          <groupId>com.fasterxml.jackson.core</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>stax2-api</artifactId>
+          <groupId>org.codehaus.woodstox</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>woodstox-core</artifactId>
+          <groupId>com.fasterxml.woodstox</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>dnsjava</artifactId>
+          <groupId>dnsjava</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>snappy-java</artifactId>
+          <groupId>org.xerial.snappy</groupId>
+        </exclusion>
+        <exclusion>
+          <artifactId>hadoop-annotations</artifactId>
+          <groupId>org.apache.hadoop</groupId>
+        </exclusion>
+      </exclusions>
+    </dependency>
+  </dependencies>
+  <properties>
+    <seaweedfs.client.version>4.00</seaweedfs.client.version>
+    <hadoop.version>3.4.0</hadoop.version>
+  </properties>
+</project>

other/java/hdfs3/pom.xml

@@ -0,0 +1,195 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <properties>
+        <seaweedfs.client.version>4.38</seaweedfs.client.version>
+        <hadoop.version>3.4.0</hadoop.version>
+    </properties>
+
+    <groupId>com.seaweedfs</groupId>
+    <artifactId>seaweedfs-hadoop3-client</artifactId>
+    <version>${seaweedfs.client.version}</version>
+
+    <name>SeaweedFS HDFS3 Client</name>
+    <description>A java client for SeaweedFS.</description>
+    <url>https://github.com/seaweedfs/seaweedfs</url>
+    <licenses>
+        <license>
+            <name>The Apache License, Version 2.0</name>
+            <url>http://www.apache.org/licenses/LICENSE-2.0.txt</url>
+        </license>
+    </licenses>
+    <developers>
+        <developer>
+            <name>Chris Lu</name>
+            <email>chris.lu@gmail.com</email>
+            <organization>SeaweedFS</organization>
+            <organizationUrl>https://seaweedfs.com</organizationUrl>
+        </developer>
+    </developers>
+    <scm>
+        <connection>scm:git:git://github.com/seaweedfs/seaweedfs.git</connection>
+        <developerConnection>scm:git:ssh://github.com:seaweedfs/seaweedfs.git</developerConnection>
+        <url>https://github.com/seaweedfs/seaweedfs/tree/master</url>
+    </scm>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-compiler-plugin</artifactId>
+                <configuration>
+                    <source>8</source>
+                    <target>8</target>
+                    <release>8</release>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-shade-plugin</artifactId>
+                <version>3.2.1</version>
+                <executions>
+                    <execution>
+                        <phase>package</phase>
+                        <goals>
+                            <goal>shade</goal>
+                        </goals>
+                        <configuration>
+                            <filters>
+                                <filter>
+                                    <artifact>*:*</artifact>
+                                    <excludes>
+                                        <exclude>META-INF/*.SF</exclude>
+                                        <exclude>META-INF/*.DSA</exclude>
+                                        <exclude>META-INF/*.RSA</exclude>
+                                        <exclude>org/slf4j/**</exclude>
+                                        <exclude>META-INF/maven/org.slf4j/**</exclude>
+                                    </excludes>
+                                </filter>
+                            </filters>
+                            <transformers>
+                                <transformer
+                                        implementation="org.apache.maven.plugins.shade.resource.ServicesResourceTransformer"/>
+                            </transformers>
+                            <relocations>
+                                <relocation>
+                                    <pattern>com.google</pattern>
+                                    <shadedPattern>shaded.com.google</shadedPattern>
+                                </relocation>
+                                <relocation>
+                                    <pattern>io.grpc.internal</pattern>
+                                    <shadedPattern>shaded.io.grpc.internal</shadedPattern>
+                                </relocation>
+                                <relocation>
+                                    <pattern>org.apache.commons</pattern>
+                                    <shadedPattern>shaded.org.apache.commons</shadedPattern>
+                                    <excludes>
+                                        <exclude>org.apache.hadoop</exclude>
+                                        <exclude>org.apache.log4j</exclude>
+                                    </excludes>
+                                </relocation>
+                                <relocation>
+                                    <pattern>org.apache.http</pattern>
+                                    <shadedPattern>shaded.org.apache.http</shadedPattern>
+                                </relocation>
+                            </relocations>
+                        </configuration>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-gpg-plugin</artifactId>
+                <version>3.2.4</version>
+                <executions>
+                    <execution>
+                        <id>sign-artifacts</id>
+                        <phase>verify</phase>
+                        <goals>
+                            <goal>sign</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.sonatype.central</groupId>
+                <artifactId>central-publishing-maven-plugin</artifactId>
+                <version>0.5.0</version>
+                <extensions>true</extensions>
+                <configuration>
+                    <publishingServerId>central</publishingServerId>
+                    <autoPublish>true</autoPublish>
+                </configuration>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-source-plugin</artifactId>
+                <version>2.2.1</version>
+                <executions>
+                    <execution>
+                        <id>attach-sources</id>
+                        <goals>
+                            <goal>jar-no-fork</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+            <plugin>
+                <groupId>org.apache.maven.plugins</groupId>
+                <artifactId>maven-javadoc-plugin</artifactId>
+                <version>3.0.1</version>
+                <executions>
+                    <execution>
+                        <id>attach-javadocs</id>
+                        <goals>
+                            <goal>jar</goal>
+                        </goals>
+                    </execution>
+                </executions>
+            </plugin>
+        </plugins>
+    </build>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.apache.hadoop</groupId>
+            <artifactId>hadoop-client</artifactId>
+            <version>${hadoop.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>com.seaweedfs</groupId>
+            <artifactId>seaweedfs-client</artifactId>
+            <version>${seaweedfs.client.version}</version>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.hadoop</groupId>
+            <artifactId>hadoop-common</artifactId>
+            <version>${hadoop.version}</version>
+            <scope>provided</scope>
+        </dependency>
+        <dependency>
+            <groupId>junit</groupId>
+            <artifactId>junit</artifactId>
+            <version>4.13.1</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.mockito</groupId>
+            <artifactId>mockito-core</artifactId>
+            <version>3.12.4</version>
+            <scope>test</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.apache.hadoop</groupId>
+            <artifactId>hadoop-common</artifactId>
+            <version>${hadoop.version}</version>
+            <scope>test</scope>
+            <type>test-jar</type>
+        </dependency>
+    </dependencies>
+
+</project>

other/java/hdfs3/src/main/java/seaweed/hdfs/BufferedByteBufferReadableInputStream.java

@@ -0,0 +1,25 @@
+package seaweed.hdfs;
+
+import org.apache.hadoop.fs.*;
+
+import java.io.IOException;
+import java.nio.ByteBuffer;
+
+public class BufferedByteBufferReadableInputStream extends BufferedFSInputStream implements ByteBufferReadable {
+
+    public BufferedByteBufferReadableInputStream(FSInputStream in, int size) {
+        super(in, size);
+        if (!(in instanceof Seekable) || !(in instanceof PositionedReadable)) {
+            throw new IllegalArgumentException("In is not an instance of Seekable or PositionedReadable");
+        }
+    }
+
+    @Override
+    public int read(ByteBuffer buf) throws IOException {
+        if (this.in instanceof ByteBufferReadable) {
+            return ((ByteBufferReadable)this.in).read(buf);
+        } else {
+            throw new UnsupportedOperationException("Byte-buffer read unsupported by input stream");
+        }
+    }
+}

other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedAbstractFileSystem.java

@@ -0,0 +1,35 @@
+/**
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License.  You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package seaweed.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.DelegateToFileSystem;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.URISyntaxException;
+
+public class SeaweedAbstractFileSystem extends DelegateToFileSystem {
+
+    SeaweedAbstractFileSystem(final URI uri, final Configuration conf)
+            throws IOException, URISyntaxException {
+        super(uri, new SeaweedFileSystem(), conf, "seaweedfs", false);
+    }
+
+}

other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedFileSystem.java

@@ -0,0 +1,651 @@
+package seaweed.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.*;
+import org.apache.hadoop.fs.permission.AclEntry;
+import org.apache.hadoop.fs.permission.AclStatus;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.apache.hadoop.util.Progressable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import seaweedfs.client.FilerProto;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.net.URI;
+import java.util.EnumSet;
+import java.util.List;
+import java.util.Map;
+
+public class SeaweedFileSystem extends FileSystem {
+
+    public static final String FS_SEAWEED_FILER_HOST = "fs.seaweed.filer.host";
+    public static final String FS_SEAWEED_FILER_PORT = "fs.seaweed.filer.port";
+    public static final String FS_SEAWEED_FILER_PORT_GRPC = "fs.seaweed.filer.port.grpc";
+    public static final int FS_SEAWEED_DEFAULT_PORT = 8888;
+    public static final String FS_SEAWEED_BUFFER_SIZE = "fs.seaweed.buffer.size";
+    public static final String FS_SEAWEED_REPLICATION = "fs.seaweed.replication";
+    public static final String FS_SEAWEED_VOLUME_SERVER_ACCESS = "fs.seaweed.volume.server.access";
+    public static final int FS_SEAWEED_DEFAULT_BUFFER_SIZE = 4 * 1024 * 1024;
+    public static final String FS_SEAWEED_FILER_CN = "fs.seaweed.filer.cn";
+
+    private static final Logger LOG = LoggerFactory.getLogger(SeaweedFileSystem.class);
+
+    private URI uri;
+    private Path workingDirectory = new Path("/");
+    private SeaweedFileSystemStore seaweedFileSystemStore;
+
+    public URI getUri() {
+        return uri;
+    }
+
+    public String getScheme() {
+        return "seaweedfs";
+    }
+
+    @Override
+    public void initialize(URI uri, Configuration conf) throws IOException { // get
+        super.initialize(uri, conf);
+
+        // get host information from uri (overrides info in conf)
+        String host = uri.getHost();
+        host = (host == null) ? conf.get(FS_SEAWEED_FILER_HOST, "localhost") : host;
+        conf.set(FS_SEAWEED_FILER_HOST, host);
+
+        // get port information from uri, (overrides info in conf)
+        int port = uri.getPort();
+        port = (port == -1) ? FS_SEAWEED_DEFAULT_PORT : port;
+        conf.setInt(FS_SEAWEED_FILER_PORT, port);
+
+        int grpcPort = conf.getInt(FS_SEAWEED_FILER_PORT_GRPC, port + 10000);
+
+        setConf(conf);
+        this.uri = uri;
+
+        String cn = conf.get(FS_SEAWEED_FILER_CN, "");
+
+        seaweedFileSystemStore = new SeaweedFileSystemStore(host, port, grpcPort, cn, conf);
+    }
+
+    @Override
+    public void close() throws IOException {
+        super.close();
+        this.seaweedFileSystemStore.close();
+    }
+
+    @Override
+    public FSDataInputStream open(Path path, int bufferSize) throws IOException {
+
+        LOG.debug("open path: {} bufferSize:{}", path, bufferSize);
+
+        path = qualify(path);
+
+        try {
+            int seaweedBufferSize = this.getConf().getInt(FS_SEAWEED_BUFFER_SIZE, FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+            FSInputStream inputStream = seaweedFileSystemStore.openFileForRead(path, statistics);
+
+            // Use BufferedFSInputStream for all streams (like RawLocalFileSystem)
+            // This ensures proper position tracking for positioned reads (critical for
+            // Parquet)
+            return new FSDataInputStream(new BufferedFSInputStream(inputStream, 4 * seaweedBufferSize));
+        } catch (Exception ex) {
+            LOG.error("Failed to open file: {} bufferSize:{}", path, bufferSize, ex);
+            throw new IOException("Failed to open file: " + path, ex);
+        }
+    }
+
+    @Override
+    public FSDataOutputStream create(Path path, FsPermission permission, final boolean overwrite, final int bufferSize,
+            final short replication, final long blockSize, final Progressable progress) throws IOException {
+
+        LOG.debug("create path: {} bufferSize:{} blockSize:{}", path, bufferSize, blockSize);
+
+        path = qualify(path);
+        final Path finalPath = path; // For use in anonymous inner class
+
+        try {
+            // Priority: 1) non-empty FS_SEAWEED_REPLICATION, 2) empty string -> filer
+            // default, 3) null -> HDFS replication
+            String replicaPlacement = this.getConf().get(FS_SEAWEED_REPLICATION);
+            if (replicaPlacement == null) {
+                // Not configured, use HDFS replication parameter. This creates a "00N"
+                // replication string,
+                // placing N (replication-1) extra replicas on different servers in the same
+                // rack.
+                replicaPlacement = String.format("%03d", replication - 1);
+            }
+            int seaweedBufferSize = this.getConf().getInt(FS_SEAWEED_BUFFER_SIZE, FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+            OutputStream outputStream = seaweedFileSystemStore.createFile(path,
+                    overwrite, permission,
+                    seaweedBufferSize, replicaPlacement);
+            return new FSDataOutputStream(outputStream, statistics);
+        } catch (Exception ex) {
+            LOG.error("Failed to create file: {} bufferSize:{} blockSize:{}", path, bufferSize, blockSize, ex);
+            throw new IOException("Failed to create file: " + path, ex);
+        }
+    }
+
+    /**
+     * {@inheritDoc}
+     *
+     * @throws FileNotFoundException if the parent directory is not present -or
+     *                               is not a directory.
+     */
+    @Override
+    public FSDataOutputStream createNonRecursive(Path path,
+            FsPermission permission,
+            EnumSet<CreateFlag> flags,
+            int bufferSize,
+            short replication,
+            long blockSize,
+            Progressable progress) throws IOException {
+        Path parent = path.getParent();
+        if (parent != null) {
+            // expect this to raise an exception if there is no parent
+            if (!getFileStatus(parent).isDirectory()) {
+                throw new FileAlreadyExistsException("Not a directory: " + parent);
+            }
+        }
+        int seaweedBufferSize = this.getConf().getInt(FS_SEAWEED_BUFFER_SIZE, FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+        return create(path, permission,
+                flags.contains(CreateFlag.OVERWRITE), bufferSize,
+                replication, seaweedBufferSize, progress);
+    }
+
+    @Override
+    public FSDataOutputStream append(Path path, int bufferSize, Progressable progressable) throws IOException {
+
+        LOG.debug("append path: {} bufferSize:{}", path, bufferSize);
+
+        path = qualify(path);
+        final Path finalPath = path; // For use in anonymous inner class
+        try {
+            int seaweedBufferSize = this.getConf().getInt(FS_SEAWEED_BUFFER_SIZE, FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+            SeaweedHadoopOutputStream outputStream = (SeaweedHadoopOutputStream) seaweedFileSystemStore.createFile(path,
+                    false, null, seaweedBufferSize, "");
+            return new FSDataOutputStream(outputStream, statistics);
+        } catch (Exception ex) {
+            LOG.error("Failed to append to file: {} bufferSize:{}", path, bufferSize, ex);
+            throw new IOException("Failed to append to file: " + path, ex);
+        }
+    }
+
+    @Override
+    public boolean rename(Path src, Path dst) throws IOException {
+
+        LOG.debug("rename path: {} => {}", src, dst);
+
+        if (src.isRoot()) {
+            return false;
+        }
+
+        if (src.equals(dst)) {
+            return true;
+        }
+        FilerProto.Entry entry = seaweedFileSystemStore.lookupEntry(dst);
+
+        Path adjustedDst = dst;
+
+        if (entry != null) {
+            FileStatus dstFileStatus = getFileStatus(dst);
+            String sourceFileName = src.getName();
+            if (!dstFileStatus.isDirectory()) {
+                return false;
+            }
+            adjustedDst = new Path(dst, sourceFileName);
+        }
+
+        Path qualifiedSrcPath = qualify(src);
+        Path qualifiedDstPath = qualify(adjustedDst);
+
+        seaweedFileSystemStore.rename(qualifiedSrcPath, qualifiedDstPath);
+        return true;
+    }
+
+    @Override
+    public boolean delete(Path path, boolean recursive) throws IOException {
+
+        LOG.debug("delete path: {} recursive:{}", path, recursive);
+
+        path = qualify(path);
+
+        FilerProto.Entry entry = seaweedFileSystemStore.lookupEntry(path);
+
+        if (entry == null) {
+            return true;
+        }
+
+        FileStatus fileStatus = getFileStatus(path);
+
+        return seaweedFileSystemStore.deleteEntries(path, fileStatus.isDirectory(), recursive);
+
+    }
+
+    @Override
+    public FileStatus[] listStatus(Path path) throws IOException {
+
+        LOG.debug("listStatus path: {}", path);
+
+        path = qualify(path);
+
+        return seaweedFileSystemStore.listEntries(path);
+    }
+
+    @Override
+    public Path getWorkingDirectory() {
+        return workingDirectory;
+    }
+
+    @Override
+    public void setWorkingDirectory(Path path) {
+        if (path.isAbsolute()) {
+            workingDirectory = path;
+        } else {
+            workingDirectory = new Path(workingDirectory, path);
+        }
+    }
+
+    @Override
+    public boolean mkdirs(Path path, FsPermission fsPermission) throws IOException {
+
+        LOG.debug("mkdirs path: {}", path);
+
+        path = qualify(path);
+
+        FilerProto.Entry entry = seaweedFileSystemStore.lookupEntry(path);
+
+        if (entry == null) {
+
+            UserGroupInformation currentUser = UserGroupInformation.getCurrentUser();
+            return seaweedFileSystemStore.createDirectory(path, currentUser,
+                    fsPermission == null ? FsPermission.getDirDefault() : fsPermission,
+                    FsPermission.getUMask(getConf()));
+
+        }
+
+        FileStatus fileStatus = getFileStatus(path);
+
+        if (fileStatus.isDirectory()) {
+            return true;
+        } else {
+            throw new FileAlreadyExistsException("Path is a file: " + path);
+        }
+    }
+
+    @Override
+    public FileStatus getFileStatus(Path path) throws IOException {
+
+        LOG.debug("getFileStatus path: {}", path);
+
+        path = qualify(path);
+
+        return seaweedFileSystemStore.getFileStatus(path);
+    }
+
+    /**
+     * Set owner of a path (i.e. a file or a directory).
+     * The parameters owner and group cannot both be null.
+     *
+     * @param path  The path
+     * @param owner If it is null, the original username remains unchanged.
+     * @param group If it is null, the original groupname remains unchanged.
+     */
+    @Override
+    public void setOwner(Path path, final String owner, final String group)
+            throws IOException {
+        LOG.debug("setOwner path: {}", path);
+        path = qualify(path);
+
+        seaweedFileSystemStore.setOwner(path, owner, group);
+    }
+
+    /**
+     * Set permission of a path.
+     *
+     * @param path       The path
+     * @param permission Access permission
+     */
+    @Override
+    public void setPermission(Path path, final FsPermission permission) throws IOException {
+        LOG.debug("setPermission path: {}", path);
+
+        if (permission == null) {
+            throw new IllegalArgumentException("The permission can't be null");
+        }
+
+        path = qualify(path);
+
+        seaweedFileSystemStore.setPermission(path, permission);
+    }
+
+    Path qualify(Path path) {
+        return path.makeQualified(uri, workingDirectory);
+    }
+
+    /**
+     * Concat existing files together.
+     *
+     * @param trg   the path to the target destination.
+     * @param psrcs the paths to the sources to use for the concatenation.
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default).
+     */
+    @Override
+    public void concat(final Path trg, final Path[] psrcs) throws IOException {
+        throw new UnsupportedOperationException("Not implemented by the " +
+                getClass().getSimpleName() + " FileSystem implementation");
+    }
+
+    /**
+     * Truncate the file in the indicated path to the indicated size.
+     * <ul>
+     * <li>Fails if path is a directory.</li>
+     * <li>Fails if path does not exist.</li>
+     * <li>Fails if path is not closed.</li>
+     * <li>Fails if new size is greater than current size.</li>
+     * </ul>
+     *
+     * @param f         The path to the file to be truncated
+     * @param newLength The size the file is to be truncated to
+     * @return <code>true</code> if the file has been truncated to the desired
+     *         <code>newLength</code> and is immediately available to be reused for
+     *         write operations such as <code>append</code>, or
+     *         <code>false</code> if a background process of adjusting the length of
+     *         the last block has been started, and clients should wait for it to
+     *         complete before proceeding with further file updates.
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default).
+     */
+    @Override
+    public boolean truncate(Path f, long newLength) throws IOException {
+        throw new UnsupportedOperationException("Not implemented by the " +
+                getClass().getSimpleName() + " FileSystem implementation");
+    }
+
+    @Override
+    public void createSymlink(final Path target, final Path link,
+            final boolean createParent) throws IOException {
+        // Supporting filesystems should override this method
+        throw new UnsupportedOperationException(
+                "Filesystem does not support symlinks!");
+    }
+
+    public boolean supportsSymlinks() {
+        return false;
+    }
+
+    /**
+     * Create a snapshot.
+     *
+     * @param path         The directory where snapshots will be taken.
+     * @param snapshotName The name of the snapshot
+     * @return the snapshot path.
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     */
+    @Override
+    public Path createSnapshot(Path path, String snapshotName)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support createSnapshot");
+    }
+
+    /**
+     * Rename a snapshot.
+     *
+     * @param path            The directory path where the snapshot was taken
+     * @param snapshotOldName Old name of the snapshot
+     * @param snapshotNewName New name of the snapshot
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void renameSnapshot(Path path, String snapshotOldName,
+            String snapshotNewName) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support renameSnapshot");
+    }
+
+    /**
+     * Delete a snapshot of a directory.
+     *
+     * @param path         The directory that the to-be-deleted snapshot belongs to
+     * @param snapshotName The name of the snapshot
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void deleteSnapshot(Path path, String snapshotName)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support deleteSnapshot");
+    }
+
+    /**
+     * Modifies ACL entries of files and directories. This method can add new ACL
+     * entries or modify the permissions on existing ACL entries. All existing
+     * ACL entries that are not specified in this call are retained without
+     * changes. (Modifications are merged into the current ACL.)
+     *
+     * @param path    Path to modify
+     * @param aclSpec List&lt;AclEntry&gt; describing modifications
+     * @throws IOException                   if an ACL could not be modified
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void modifyAclEntries(Path path, List<AclEntry> aclSpec)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support modifyAclEntries");
+    }
+
+    /**
+     * Removes ACL entries from files and directories. Other ACL entries are
+     * retained.
+     *
+     * @param path    Path to modify
+     * @param aclSpec List describing entries to remove
+     * @throws IOException                   if an ACL could not be modified
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void removeAclEntries(Path path, List<AclEntry> aclSpec)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support removeAclEntries");
+    }
+
+    /**
+     * Removes all default ACL entries from files and directories.
+     *
+     * @param path Path to modify
+     * @throws IOException                   if an ACL could not be modified
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void removeDefaultAcl(Path path)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support removeDefaultAcl");
+    }
+
+    /**
+     * Removes all but the base ACL entries of files and directories. The entries
+     * for user, group, and others are retained for compatibility with permission
+     * bits.
+     *
+     * @param path Path to modify
+     * @throws IOException                   if an ACL could not be removed
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void removeAcl(Path path)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support removeAcl");
+    }
+
+    /**
+     * Fully replaces ACL of files and directories, discarding all existing
+     * entries.
+     *
+     * @param path    Path to modify
+     * @param aclSpec List describing modifications, which must include entries
+     *                for user, group, and others for compatibility with permission
+     *                bits.
+     * @throws IOException                   if an ACL could not be modified
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void setAcl(Path path, List<AclEntry> aclSpec) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support setAcl");
+    }
+
+    /**
+     * Gets the ACL of a file or directory.
+     *
+     * @param path Path to get
+     * @return AclStatus describing the ACL of the file or directory
+     * @throws IOException                   if an ACL could not be read
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public AclStatus getAclStatus(Path path) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support getAclStatus");
+    }
+
+    /**
+     * Set an xattr of a file or directory.
+     * The name must be prefixed with the namespace followed by ".". For example,
+     * "user.attr".
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path  Path to modify
+     * @param name  xattr name.
+     * @param value xattr value.
+     * @param flag  xattr set flag
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void setXAttr(Path path, String name, byte[] value,
+            EnumSet<XAttrSetFlag> flag) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support setXAttr");
+    }
+
+    /**
+     * Get an xattr name and value for a file or directory.
+     * The name must be prefixed with the namespace followed by ".". For example,
+     * "user.attr".
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path Path to get extended attribute
+     * @param name xattr name.
+     * @return byte[] xattr value.
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public byte[] getXAttr(Path path, String name) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support getXAttr");
+    }
+
+    /**
+     * Get all of the xattr name/value pairs for a file or directory.
+     * Only those xattrs which the logged-in user has permissions to view
+     * are returned.
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path Path to get extended attributes
+     * @return Map describing the XAttrs of the file or directory
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public Map<String, byte[]> getXAttrs(Path path) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support getXAttrs");
+    }
+
+    /**
+     * Get all of the xattrs name/value pairs for a file or directory.
+     * Only those xattrs which the logged-in user has permissions to view
+     * are returned.
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path  Path to get extended attributes
+     * @param names XAttr names.
+     * @return Map describing the XAttrs of the file or directory
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public Map<String, byte[]> getXAttrs(Path path, List<String> names)
+            throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support getXAttrs");
+    }
+
+    /**
+     * Get all of the xattr names for a file or directory.
+     * Only those xattr names which the logged-in user has permissions to view
+     * are returned.
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path Path to get extended attributes
+     * @return List{@literal <String>} of the XAttr names of the file or directory
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public List<String> listXAttrs(Path path) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support listXAttrs");
+    }
+
+    /**
+     * Remove an xattr of a file or directory.
+     * The name must be prefixed with the namespace followed by ".". For example,
+     * "user.attr".
+     * <p>
+     * Refer to the HDFS extended attributes user documentation for details.
+     *
+     * @param path Path to remove extended attribute
+     * @param name xattr name
+     * @throws IOException                   IO failure
+     * @throws UnsupportedOperationException if the operation is unsupported
+     *                                       (default outcome).
+     */
+    @Override
+    public void removeXAttr(Path path, String name) throws IOException {
+        throw new UnsupportedOperationException(getClass().getSimpleName()
+                + " doesn't support removeXAttr");
+    }
+
+}

other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedFileSystemStore.java

@@ -0,0 +1,293 @@
+package seaweed.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSInputStream;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.apache.hadoop.security.UserGroupInformation;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import seaweedfs.client.*;
+
+import java.io.FileNotFoundException;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import static seaweed.hdfs.SeaweedFileSystem.*;
+
+public class SeaweedFileSystemStore {
+
+    private static final Logger LOG = LoggerFactory.getLogger(SeaweedFileSystemStore.class);
+
+    private FilerClient filerClient;
+    private Configuration conf;
+
+    public SeaweedFileSystemStore(String host, int port, int grpcPort, String cn, Configuration conf) {
+        filerClient = new FilerClient(host, port, grpcPort, cn);
+        this.conf = conf;
+        String volumeServerAccessMode = this.conf.get(FS_SEAWEED_VOLUME_SERVER_ACCESS, "direct");
+        if (volumeServerAccessMode.equals("publicUrl")) {
+            filerClient.setAccessVolumeServerByPublicUrl();
+        } else if (volumeServerAccessMode.equals("filerProxy")) {
+            filerClient.setAccessVolumeServerByFilerProxy();
+        }
+    }
+
+    public void close() {
+        try {
+            this.filerClient.shutdown();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+    }
+
+    public static String getParentDirectory(Path path) {
+        return path.isRoot() ? "/" : path.getParent().toUri().getPath();
+    }
+
+    static int permissionToMode(FsPermission permission, boolean isDirectory) {
+        int p = permission.toShort();
+        if (isDirectory) {
+            p = p | 1 << 31;
+        }
+        return p;
+    }
+
+    public boolean createDirectory(final Path path, UserGroupInformation currentUser,
+            final FsPermission permission, final FsPermission umask) {
+
+        LOG.debug("createDirectory path: {} permission: {} umask: {}",
+                path,
+                permission,
+                umask);
+
+        return filerClient.mkdirs(
+                path.toUri().getPath(),
+                permissionToMode(permission, true),
+                currentUser.getUserName(),
+                currentUser.getGroupNames());
+    }
+
+    public FileStatus[] listEntries(final Path path) throws IOException {
+        LOG.debug("listEntries path: {}", path);
+
+        FileStatus pathStatus = getFileStatus(path);
+
+        if (pathStatus == null) {
+            return new FileStatus[0];
+        }
+
+        if (!pathStatus.isDirectory()) {
+            return new FileStatus[] { pathStatus };
+        }
+
+        List<FileStatus> fileStatuses = new ArrayList<FileStatus>();
+
+        List<FilerProto.Entry> entries = filerClient.listEntries(path.toUri().getPath());
+
+        for (FilerProto.Entry entry : entries) {
+
+            FileStatus fileStatus = doGetFileStatus(new Path(path, entry.getName()), entry);
+
+            fileStatuses.add(fileStatus);
+        }
+        LOG.debug("listEntries path: {} size {}", fileStatuses, fileStatuses.size());
+        return fileStatuses.toArray(new FileStatus[0]);
+
+    }
+
+    public FileStatus getFileStatus(final Path path) throws IOException {
+
+        FilerProto.Entry entry = lookupEntry(path);
+        if (entry == null) {
+            throw new FileNotFoundException("File does not exist: " + path);
+        }
+        LOG.debug("doGetFileStatus path:{} entry:{}", path, entry);
+
+        FileStatus fileStatus = doGetFileStatus(path, entry);
+        return fileStatus;
+    }
+
+    public boolean deleteEntries(final Path path, boolean isDirectory, boolean recursive) {
+        LOG.debug("deleteEntries path: {} isDirectory {} recursive: {}",
+                path,
+                String.valueOf(isDirectory),
+                String.valueOf(recursive));
+
+        if (path.isRoot()) {
+            return true;
+        }
+
+        if (recursive && isDirectory) {
+            List<FilerProto.Entry> entries = filerClient.listEntries(path.toUri().getPath());
+            for (FilerProto.Entry entry : entries) {
+                deleteEntries(new Path(path, entry.getName()), entry.getIsDirectory(), true);
+            }
+        }
+
+        return filerClient.deleteEntry(getParentDirectory(path), path.getName(), true, recursive, true);
+    }
+
+    private FileStatus doGetFileStatus(Path path, FilerProto.Entry entry) {
+        FilerProto.FuseAttributes attributes = entry.getAttributes();
+        long length = SeaweedRead.fileSize(entry);
+        boolean isDir = entry.getIsDirectory();
+        int block_replication = 1;
+        int blocksize = this.conf.getInt(FS_SEAWEED_BUFFER_SIZE, FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+        long modification_time = attributes.getMtime() * 1000; // milliseconds
+        long access_time = 0;
+        FsPermission permission = FsPermission.createImmutable((short) attributes.getFileMode());
+        String owner = attributes.getUserName();
+        String group = attributes.getGroupNameCount() > 0 ? attributes.getGroupName(0) : "";
+        return new FileStatus(length, isDir, block_replication, blocksize,
+                modification_time, access_time, permission, owner, group, null, path);
+    }
+
+    public FilerProto.Entry lookupEntry(Path path) {
+
+        return filerClient.lookupEntry(getParentDirectory(path), path.getName());
+
+    }
+
+    public void rename(Path source, Path destination) {
+
+        LOG.debug("rename source: {} destination:{}", source, destination);
+
+        if (source.isRoot()) {
+            return;
+        }
+
+        FilerProto.Entry entry = lookupEntry(source);
+        if (entry == null) {
+            LOG.warn("rename non-existing source: {}", source);
+            return;
+        }
+
+        filerClient.mv(source.toUri().getPath(), destination.toUri().getPath());
+    }
+
+    public OutputStream createFile(final Path path,
+            final boolean overwrite,
+            FsPermission permission,
+            int bufferSize,
+            String replication) throws IOException {
+
+        permission = permission == null ? FsPermission.getFileDefault() : permission;
+
+        
+        LOG.debug("createFile path: {} overwrite: {} permission: {}",
+                path,
+                overwrite,
+                permission.toString());
+
+        UserGroupInformation userGroupInformation = UserGroupInformation.getCurrentUser();
+        long now = System.currentTimeMillis() / 1000L;
+
+        FilerProto.Entry.Builder entry = null;
+        long writePosition = 0;
+        if (!overwrite) {
+            FilerProto.Entry existingEntry = lookupEntry(path);
+            LOG.debug("createFile merged entry path:{} existingEntry:{}", path, existingEntry);
+            if (existingEntry != null) {
+                entry = FilerProto.Entry.newBuilder();
+                entry.mergeFrom(existingEntry);
+                entry.clearContent();
+                entry.getAttributesBuilder().setMtime(now);
+                LOG.debug("createFile merged entry path:{} entry:{} from:{}", path, entry, existingEntry);
+                writePosition = SeaweedRead.fileSize(existingEntry);
+            }
+        }
+        if (entry == null) {
+            entry = FilerProto.Entry.newBuilder()
+                    .setName(path.getName())
+                    .setIsDirectory(false)
+                    .setAttributes(FilerProto.FuseAttributes.newBuilder()
+                            .setFileMode(permissionToMode(permission, false))
+                            .setCrtime(now)
+                            .setMtime(now)
+                            .setUserName(userGroupInformation.getUserName())
+                            .clearGroupName()
+                            .addAllGroupName(Arrays.asList(userGroupInformation.getGroupNames())));
+            SeaweedWrite.writeMeta(filerClient, getParentDirectory(path), entry);
+        }
+
+        
+        return new SeaweedHadoopOutputStream(filerClient, path.toString(), entry, writePosition, bufferSize,
+                replication);
+
+    }
+
+    public FSInputStream openFileForRead(final Path path, FileSystem.Statistics statistics) throws IOException {
+
+        LOG.debug("openFileForRead path:{}", path);
+
+        FilerProto.Entry entry = lookupEntry(path);
+
+        if (entry == null) {
+            throw new FileNotFoundException("read non-exist file " + path);
+        }
+
+        return new SeaweedHadoopInputStream(filerClient,
+                statistics,
+                path.toUri().getPath(),
+                entry);
+    }
+
+    public void setOwner(Path path, String owner, String group) {
+
+        LOG.debug("setOwner path:{} owner:{} group:{}", path, owner, group);
+
+        FilerProto.Entry entry = lookupEntry(path);
+        if (entry == null) {
+            LOG.debug("setOwner path:{} entry:{}", path, entry);
+            return;
+        }
+
+        FilerProto.Entry.Builder entryBuilder = entry.toBuilder();
+        FilerProto.FuseAttributes.Builder attributesBuilder = entry.getAttributes().toBuilder();
+
+        if (owner != null) {
+            attributesBuilder.setUserName(owner);
+        }
+        if (group != null) {
+            attributesBuilder.clearGroupName();
+            attributesBuilder.addGroupName(group);
+        }
+
+        entryBuilder.setAttributes(attributesBuilder);
+
+        LOG.debug("setOwner path:{} entry:{}", path, entryBuilder);
+
+        filerClient.updateEntry(getParentDirectory(path), entryBuilder.build());
+
+    }
+
+    public void setPermission(Path path, FsPermission permission) {
+
+        LOG.debug("setPermission path:{} permission:{}", path, permission);
+
+        FilerProto.Entry entry = lookupEntry(path);
+        if (entry == null) {
+            LOG.debug("setPermission path:{} entry:{}", path, entry);
+            return;
+        }
+
+        FilerProto.Entry.Builder entryBuilder = entry.toBuilder();
+        FilerProto.FuseAttributes.Builder attributesBuilder = entry.getAttributes().toBuilder();
+
+        attributesBuilder.setFileMode(permissionToMode(permission, entry.getIsDirectory()));
+
+        entryBuilder.setAttributes(attributesBuilder);
+
+        LOG.debug("setPermission path:{} entry:{}", path, entryBuilder);
+
+        filerClient.updateEntry(getParentDirectory(path), entryBuilder.build());
+
+    }
+
+}

other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedHadoopInputStream.java

@@ -0,0 +1,153 @@
+package seaweed.hdfs;
+
+// based on org.apache.hadoop.fs.azurebfs.services.AbfsInputStream
+
+import org.apache.hadoop.fs.FSInputStream;
+import org.apache.hadoop.fs.FileSystem.Statistics;
+import seaweedfs.client.FilerClient;
+import seaweedfs.client.FilerProto;
+import seaweedfs.client.SeaweedInputStream;
+
+import java.io.EOFException;
+import java.io.IOException;
+
+/**
+ * SeaweedFS Hadoop InputStream.
+ * 
+ * NOTE: Does NOT implement ByteBufferReadable to match RawLocalFileSystem
+ * behavior.
+ * This ensures BufferedFSInputStream is used, which properly handles position
+ * tracking
+ * for positioned reads (critical for Parquet and other formats).
+ */
+public class SeaweedHadoopInputStream extends FSInputStream {
+
+    private final SeaweedInputStream seaweedInputStream;
+    private final Statistics statistics;
+    private final String path;
+
+    public SeaweedHadoopInputStream(
+            final FilerClient filerClient,
+            final Statistics statistics,
+            final String path,
+            final FilerProto.Entry entry) throws IOException {
+        this.seaweedInputStream = new SeaweedInputStream(filerClient, path, entry);
+        this.statistics = statistics;
+        this.path = path;
+    }
+
+    @Override
+    public int read() throws IOException {
+        return seaweedInputStream.read();
+    }
+
+    @Override
+    public int read(final byte[] b, final int off, final int len) throws IOException {
+        return seaweedInputStream.read(b, off, len);
+    }
+
+    /**
+     * Seek to given position in stream.
+     *
+     * @param n position to seek to
+     * @throws IOException  if there is an error
+     * @throws EOFException if attempting to seek past end of file
+     */
+    @Override
+    public synchronized void seek(long n) throws IOException {
+        seaweedInputStream.seek(n);
+    }
+
+    @Override
+    public synchronized long skip(long n) throws IOException {
+        return seaweedInputStream.skip(n);
+    }
+
+    /**
+     * Return the size of the remaining available bytes
+     * if the size is less than or equal to {@link Integer#MAX_VALUE},
+     * otherwise, return {@link Integer#MAX_VALUE}.
+     * <p>
+     * This is to match the behavior of DFSInputStream.available(),
+     * which some clients may rely on (HBase write-ahead log reading in
+     * particular).
+     */
+    @Override
+    public synchronized int available() throws IOException {
+        return seaweedInputStream.available();
+    }
+
+    /**
+     * Returns the length of the file that this stream refers to. Note that the
+     * length returned is the length
+     * as of the time the Stream was opened. Specifically, if there have been
+     * subsequent appends to the file,
+     * they won't be reflected in the returned length.
+     *
+     * @return length of the file.
+     * @throws IOException if the stream is closed
+     */
+    public long length() throws IOException {
+        return seaweedInputStream.length();
+    }
+
+    /**
+     * Return the current offset from the start of the file
+     *
+     * @throws IOException throws {@link IOException} if there is an error
+     */
+    @Override
+    public synchronized long getPos() throws IOException {
+        return seaweedInputStream.getPos();
+    }
+
+    public String getPath() {
+        return path;
+    }
+
+    /**
+     * Seeks a different copy of the data. Returns true if
+     * found a new source, false otherwise.
+     *
+     * @throws IOException throws {@link IOException} if there is an error
+     */
+    @Override
+    public boolean seekToNewSource(long l) throws IOException {
+        return false;
+    }
+
+    @Override
+    public synchronized void close() throws IOException {
+        seaweedInputStream.close();
+    }
+
+    /**
+     * Not supported by this stream. Throws {@link UnsupportedOperationException}
+     *
+     * @param readlimit ignored
+     */
+    @Override
+    public synchronized void mark(int readlimit) {
+        throw new UnsupportedOperationException("mark()/reset() not supported on this stream");
+    }
+
+    /**
+     * Not supported by this stream. Throws {@link UnsupportedOperationException}
+     */
+    @Override
+    public synchronized void reset() throws IOException {
+        throw new UnsupportedOperationException("mark()/reset() not supported on this stream");
+    }
+
+    /**
+     * gets whether mark and reset are supported by
+     * {@code SeaweedHadoopInputStream}.
+     * Always returns false.
+     *
+     * @return always {@code false}
+     */
+    @Override
+    public boolean markSupported() {
+        return false;
+    }
+}

other/java/hdfs3/src/main/java/seaweed/hdfs/SeaweedHadoopOutputStream.java

@@ -0,0 +1,71 @@
+package seaweed.hdfs;
+
+// adapted from org.apache.hadoop.fs.azurebfs.services.AbfsOutputStream
+
+import org.apache.hadoop.fs.StreamCapabilities;
+import org.apache.hadoop.fs.Syncable;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+import seaweedfs.client.FilerClient;
+import seaweedfs.client.FilerProto;
+import seaweedfs.client.SeaweedOutputStream;
+
+import java.io.IOException;
+import java.util.Locale;
+
+public class SeaweedHadoopOutputStream extends SeaweedOutputStream implements Syncable, StreamCapabilities {
+
+    private static final Logger LOG = LoggerFactory.getLogger(SeaweedHadoopOutputStream.class);
+
+    public SeaweedHadoopOutputStream(FilerClient filerClient, final String path, FilerProto.Entry.Builder entry,
+            final long position, final int bufferSize, final String replication) {
+        super(filerClient, path, entry, position, bufferSize, replication);
+
+    }
+
+    /**
+     * Similar to posix fsync, flush out the data in client's user buffer
+     * all the way to the disk device (but the disk may have it in its cache).
+     *
+     * @throws IOException if error occurs
+     */
+    @Override
+    public void hsync() throws IOException {
+
+        if (supportFlush) {
+            flushInternal();
+        }
+    }
+
+    /**
+     * Flush out the data in client's user buffer. After the return of
+     * this call, new readers will see the data.
+     *
+     * @throws IOException if any error occurs
+     */
+    @Override
+    public void hflush() throws IOException {
+
+        if (supportFlush) {
+            flushInternal();
+        }
+    }
+
+    /**
+     * Query the stream for a specific capability.
+     *
+     * @param capability string to query the stream support for.
+     * @return true for hsync and hflush.
+     */
+    @Override
+    public boolean hasCapability(String capability) {
+        switch (capability.toLowerCase(Locale.ENGLISH)) {
+            case StreamCapabilities.HSYNC:
+            case StreamCapabilities.HFLUSH:
+                return supportFlush;
+            default:
+                return false;
+        }
+    }
+
+}

other/java/hdfs3/src/test/java/seaweed/hdfs/SeaweedFileSystemConfigTest.java

@@ -0,0 +1,90 @@
+package seaweed.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.Path;
+import org.junit.Before;
+import org.junit.Test;
+
+import static org.junit.Assert.*;
+
+/**
+ * Unit tests for SeaweedFileSystem configuration that don't require a running SeaweedFS instance.
+ * 
+ * These tests verify basic properties and constants.
+ */
+public class SeaweedFileSystemConfigTest {
+
+    private SeaweedFileSystem fs;
+    private Configuration conf;
+
+    @Before
+    public void setUp() {
+        fs = new SeaweedFileSystem();
+        conf = new Configuration();
+    }
+
+    @Test
+    public void testScheme() {
+        assertEquals("seaweedfs", fs.getScheme());
+    }
+
+    @Test
+    public void testConstants() {
+        // Test that constants are defined correctly
+        assertEquals("fs.seaweed.filer.host", SeaweedFileSystem.FS_SEAWEED_FILER_HOST);
+        assertEquals("fs.seaweed.filer.port", SeaweedFileSystem.FS_SEAWEED_FILER_PORT);
+        assertEquals("fs.seaweed.filer.port.grpc", SeaweedFileSystem.FS_SEAWEED_FILER_PORT_GRPC);
+        assertEquals(8888, SeaweedFileSystem.FS_SEAWEED_DEFAULT_PORT);
+        assertEquals("fs.seaweed.buffer.size", SeaweedFileSystem.FS_SEAWEED_BUFFER_SIZE);
+        assertEquals(4 * 1024 * 1024, SeaweedFileSystem.FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+        assertEquals("fs.seaweed.replication", SeaweedFileSystem.FS_SEAWEED_REPLICATION);
+        assertEquals("fs.seaweed.volume.server.access", SeaweedFileSystem.FS_SEAWEED_VOLUME_SERVER_ACCESS);
+        assertEquals("fs.seaweed.filer.cn", SeaweedFileSystem.FS_SEAWEED_FILER_CN);
+    }
+
+    @Test
+    public void testWorkingDirectoryPathOperations() {
+        // Test path operations that don't require initialization
+        Path testPath = new Path("/test/path");
+        assertTrue("Path should be absolute", testPath.isAbsolute());
+        assertEquals("/test/path", testPath.toUri().getPath());
+        
+        Path childPath = new Path(testPath, "child");
+        assertEquals("/test/path/child", childPath.toUri().getPath());
+    }
+
+    @Test
+    public void testConfigurationProperties() {
+        // Test that configuration can be set and read
+        conf.set(SeaweedFileSystem.FS_SEAWEED_FILER_HOST, "testhost");
+        assertEquals("testhost", conf.get(SeaweedFileSystem.FS_SEAWEED_FILER_HOST));
+        
+        conf.setInt(SeaweedFileSystem.FS_SEAWEED_FILER_PORT, 9999);
+        assertEquals(9999, conf.getInt(SeaweedFileSystem.FS_SEAWEED_FILER_PORT, 0));
+        
+        conf.setInt(SeaweedFileSystem.FS_SEAWEED_BUFFER_SIZE, 8 * 1024 * 1024);
+        assertEquals(8 * 1024 * 1024, conf.getInt(SeaweedFileSystem.FS_SEAWEED_BUFFER_SIZE, 0));
+        
+        conf.set(SeaweedFileSystem.FS_SEAWEED_REPLICATION, "001");
+        assertEquals("001", conf.get(SeaweedFileSystem.FS_SEAWEED_REPLICATION));
+        
+        conf.set(SeaweedFileSystem.FS_SEAWEED_VOLUME_SERVER_ACCESS, "publicUrl");
+        assertEquals("publicUrl", conf.get(SeaweedFileSystem.FS_SEAWEED_VOLUME_SERVER_ACCESS));
+        
+        conf.set(SeaweedFileSystem.FS_SEAWEED_FILER_CN, "test-cn");
+        assertEquals("test-cn", conf.get(SeaweedFileSystem.FS_SEAWEED_FILER_CN));
+    }
+
+    @Test
+    public void testDefaultBufferSize() {
+        // Test default buffer size constant
+        int expected = 4 * 1024 * 1024; // 4MB
+        assertEquals(expected, SeaweedFileSystem.FS_SEAWEED_DEFAULT_BUFFER_SIZE);
+    }
+
+    @Test
+    public void testDefaultPort() {
+        // Test default port constant
+        assertEquals(8888, SeaweedFileSystem.FS_SEAWEED_DEFAULT_PORT);
+    }
+}

other/java/hdfs3/src/test/java/seaweed/hdfs/SeaweedFileSystemTest.java

@@ -0,0 +1,379 @@
+package seaweed.hdfs;
+
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileStatus;
+import org.apache.hadoop.fs.Path;
+import org.apache.hadoop.fs.permission.FsPermission;
+import org.junit.After;
+import org.junit.Before;
+import org.junit.Test;
+
+import java.io.IOException;
+import java.net.URI;
+
+import static org.junit.Assert.*;
+
+/**
+ * Unit tests for SeaweedFileSystem.
+ * 
+ * These tests verify basic FileSystem operations against a SeaweedFS backend.
+ * Note: These tests require a running SeaweedFS filer instance.
+ * 
+ * To run tests, ensure SeaweedFS is running with default ports:
+ * - Filer HTTP: 8888
+ * - Filer gRPC: 18888
+ * 
+ * Set environment variable SEAWEEDFS_TEST_ENABLED=true to enable these tests.
+ */
+public class SeaweedFileSystemTest {
+
+    private SeaweedFileSystem fs;
+    private Configuration conf;
+    private static final String TEST_ROOT = "/test-hdfs3";
+    private static final boolean TESTS_ENABLED = 
+        "true".equalsIgnoreCase(System.getenv("SEAWEEDFS_TEST_ENABLED"));
+
+    @Before
+    public void setUp() throws Exception {
+        if (!TESTS_ENABLED) {
+            return;
+        }
+        
+        conf = new Configuration();
+        conf.set("fs.seaweed.filer.host", "localhost");
+        conf.setInt("fs.seaweed.filer.port", 8888);
+        conf.setInt("fs.seaweed.filer.port.grpc", 18888);
+        
+        fs = new SeaweedFileSystem();
+        URI uri = new URI("seaweedfs://localhost:8888/");
+        fs.initialize(uri, conf);
+        
+        // Clean up any existing test directory
+        Path testPath = new Path(TEST_ROOT);
+        if (fs.exists(testPath)) {
+            fs.delete(testPath, true);
+        }
+    }
+
+    @After
+    public void tearDown() throws Exception {
+        if (!TESTS_ENABLED || fs == null) {
+            return;
+        }
+        
+        // Clean up test directory
+        Path testPath = new Path(TEST_ROOT);
+        if (fs.exists(testPath)) {
+            fs.delete(testPath, true);
+        }
+        
+        fs.close();
+    }
+
+    @Test
+    public void testInitialization() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        assertNotNull(fs);
+        assertEquals("seaweedfs", fs.getScheme());
+        assertNotNull(fs.getUri());
+        assertEquals("/", fs.getWorkingDirectory().toUri().getPath());
+    }
+
+    @Test
+    public void testMkdirs() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testDir = new Path(TEST_ROOT + "/testdir");
+        assertTrue("Failed to create directory", fs.mkdirs(testDir));
+        assertTrue("Directory should exist", fs.exists(testDir));
+        
+        FileStatus status = fs.getFileStatus(testDir);
+        assertTrue("Path should be a directory", status.isDirectory());
+    }
+
+    @Test
+    public void testCreateAndReadFile() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/testfile.txt");
+        String testContent = "Hello, SeaweedFS!";
+        
+        // Create and write to file
+        FSDataOutputStream out = fs.create(testFile, FsPermission.getDefault(), 
+            false, 4096, (short) 1, 4 * 1024 * 1024, null);
+        assertNotNull("Output stream should not be null", out);
+        out.write(testContent.getBytes());
+        out.close();
+        
+        // Verify file exists
+        assertTrue("File should exist", fs.exists(testFile));
+        
+        // Read and verify content
+        FSDataInputStream in = fs.open(testFile, 4096);
+        assertNotNull("Input stream should not be null", in);
+        byte[] buffer = new byte[testContent.length()];
+        int bytesRead = in.read(buffer);
+        in.close();
+        
+        assertEquals("Should read all bytes", testContent.length(), bytesRead);
+        assertEquals("Content should match", testContent, new String(buffer));
+    }
+
+    @Test
+    public void testFileStatus() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/statustest.txt");
+        String content = "test content";
+        
+        FSDataOutputStream out = fs.create(testFile);
+        out.write(content.getBytes());
+        out.close();
+        
+        FileStatus status = fs.getFileStatus(testFile);
+        assertNotNull("FileStatus should not be null", status);
+        assertFalse("Should not be a directory", status.isDirectory());
+        assertTrue("Should be a file", status.isFile());
+        assertEquals("File length should match", content.length(), status.getLen());
+        assertNotNull("Path should not be null", status.getPath());
+    }
+
+    @Test
+    public void testListStatus() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testDir = new Path(TEST_ROOT + "/listtest");
+        fs.mkdirs(testDir);
+        
+        // Create multiple files
+        for (int i = 0; i < 3; i++) {
+            Path file = new Path(testDir, "file" + i + ".txt");
+            FSDataOutputStream out = fs.create(file);
+            out.write(("content" + i).getBytes());
+            out.close();
+        }
+        
+        FileStatus[] statuses = fs.listStatus(testDir);
+        assertNotNull("List should not be null", statuses);
+        assertEquals("Should have 3 files", 3, statuses.length);
+    }
+
+    @Test
+    public void testRename() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path srcFile = new Path(TEST_ROOT + "/source.txt");
+        Path dstFile = new Path(TEST_ROOT + "/destination.txt");
+        String content = "rename test";
+        
+        // Create source file
+        FSDataOutputStream out = fs.create(srcFile);
+        out.write(content.getBytes());
+        out.close();
+        
+        assertTrue("Source file should exist", fs.exists(srcFile));
+        
+        // Rename
+        assertTrue("Rename should succeed", fs.rename(srcFile, dstFile));
+        
+        // Verify
+        assertFalse("Source file should not exist", fs.exists(srcFile));
+        assertTrue("Destination file should exist", fs.exists(dstFile));
+        
+        // Verify content preserved
+        FSDataInputStream in = fs.open(dstFile);
+        byte[] buffer = new byte[content.length()];
+        in.read(buffer);
+        in.close();
+        assertEquals("Content should be preserved", content, new String(buffer));
+    }
+
+    @Test
+    public void testDelete() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/deletetest.txt");
+        
+        // Create file
+        FSDataOutputStream out = fs.create(testFile);
+        out.write("delete me".getBytes());
+        out.close();
+        
+        assertTrue("File should exist before delete", fs.exists(testFile));
+        
+        // Delete
+        assertTrue("Delete should succeed", fs.delete(testFile, false));
+        assertFalse("File should not exist after delete", fs.exists(testFile));
+    }
+
+    @Test
+    public void testDeleteDirectory() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testDir = new Path(TEST_ROOT + "/deletedir");
+        Path testFile = new Path(testDir, "file.txt");
+        
+        // Create directory with file
+        fs.mkdirs(testDir);
+        FSDataOutputStream out = fs.create(testFile);
+        out.write("content".getBytes());
+        out.close();
+        
+        assertTrue("Directory should exist", fs.exists(testDir));
+        assertTrue("File should exist", fs.exists(testFile));
+        
+        // Recursive delete
+        assertTrue("Recursive delete should succeed", fs.delete(testDir, true));
+        assertFalse("Directory should not exist after delete", fs.exists(testDir));
+        assertFalse("File should not exist after delete", fs.exists(testFile));
+    }
+
+    @Test
+    public void testAppend() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/appendtest.txt");
+        String initialContent = "initial";
+        String appendContent = " appended";
+        
+        // Create initial file
+        FSDataOutputStream out = fs.create(testFile);
+        out.write(initialContent.getBytes());
+        out.close();
+        
+        // Append
+        FSDataOutputStream appendOut = fs.append(testFile, 4096, null);
+        assertNotNull("Append stream should not be null", appendOut);
+        appendOut.write(appendContent.getBytes());
+        appendOut.close();
+        
+        // Verify combined content
+        FSDataInputStream in = fs.open(testFile);
+        byte[] buffer = new byte[initialContent.length() + appendContent.length()];
+        int bytesRead = in.read(buffer);
+        in.close();
+        
+        String expected = initialContent + appendContent;
+        assertEquals("Should read all bytes", expected.length(), bytesRead);
+        assertEquals("Content should match", expected, new String(buffer));
+    }
+
+    @Test
+    public void testSetWorkingDirectory() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path originalWd = fs.getWorkingDirectory();
+        assertEquals("Original working directory should be /", "/", originalWd.toUri().getPath());
+        
+        Path newWd = new Path(TEST_ROOT);
+        fs.mkdirs(newWd);
+        fs.setWorkingDirectory(newWd);
+        
+        Path currentWd = fs.getWorkingDirectory();
+        assertTrue("Working directory should be updated", 
+            currentWd.toUri().getPath().contains(TEST_ROOT));
+    }
+
+    @Test
+    public void testSetPermission() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/permtest.txt");
+        
+        // Create file
+        FSDataOutputStream out = fs.create(testFile);
+        out.write("permission test".getBytes());
+        out.close();
+        
+        // Set permission
+        FsPermission newPerm = new FsPermission((short) 0644);
+        fs.setPermission(testFile, newPerm);
+        
+        FileStatus status = fs.getFileStatus(testFile);
+        assertNotNull("Permission should not be null", status.getPermission());
+    }
+
+    @Test
+    public void testSetOwner() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path testFile = new Path(TEST_ROOT + "/ownertest.txt");
+        
+        // Create file
+        FSDataOutputStream out = fs.create(testFile);
+        out.write("owner test".getBytes());
+        out.close();
+        
+        // Set owner - this may not fail even if not fully implemented
+        fs.setOwner(testFile, "testuser", "testgroup");
+        
+        // Just verify the call doesn't throw an exception
+        FileStatus status = fs.getFileStatus(testFile);
+        assertNotNull("FileStatus should not be null", status);
+    }
+
+    @Test
+    public void testRenameToExistingDirectory() throws Exception {
+        if (!TESTS_ENABLED) {
+            System.out.println("Skipping test - SEAWEEDFS_TEST_ENABLED not set");
+            return;
+        }
+        
+        Path srcFile = new Path(TEST_ROOT + "/movefile.txt");
+        Path dstDir = new Path(TEST_ROOT + "/movedir");
+        
+        // Create source file and destination directory
+        FSDataOutputStream out = fs.create(srcFile);
+        out.write("move test".getBytes());
+        out.close();
+        fs.mkdirs(dstDir);
+        
+        // Rename file to existing directory (should move file into directory)
+        assertTrue("Rename to directory should succeed", fs.rename(srcFile, dstDir));
+        
+        // File should be moved into the directory
+        Path expectedLocation = new Path(dstDir, srcFile.getName());
+        assertTrue("File should exist in destination directory", fs.exists(expectedLocation));
+        assertFalse("Source file should not exist", fs.exists(srcFile));
+    }
+}
+