update

Author: ArnavBalyan

parquet-common/src/main/java/org/apache/parquet/storage/Storage.java

@@ -0,0 +1,56 @@
+/*
+ *  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 org.apache.parquet.storage;
+
+import java.net.URI;
+
+/**
+ * Simple helper to select a {@link StorageProvider} implementation based on a
+ * Hadoop/NIO constructs. This keeps provider discovery logic outside of call-sites.
+ */
+public final class Storage {
+  private Storage() {}
+
+  /**
+   * Return the appropriate provider for the given URI scheme.
+   * - file:// or no scheme → NIO provider
+   * - hdfs:// → Hadoop provider (if available)
+   */
+  public static StorageProvider select(URI uri) {
+    final String scheme = uri == null ? null : uri.getScheme();
+
+    if (scheme == null || "file".equals(scheme)) {
+      return new org.apache.parquet.storage.impl.NioStorageProvider();
+    }
+
+    try {
+      Class<?> confClass = Class.forName("org.apache.hadoop.conf.Configuration");
+      Object conf = confClass.getDeclaredConstructor().newInstance();
+      Class<?> providerClass = Class.forName("org.apache.parquet.storage.impl.hadoop.HadoopStorageProvider");
+      return (StorageProvider) providerClass.getConstructor(confClass).newInstance(conf);
+    } catch (ClassNotFoundException e) {
+      throw new IllegalStateException(
+          "Hadoop not on classpath for URI scheme hdfs, please ensure hadoop dependencies are available in classpath",
+          e);
+    } catch (ReflectiveOperationException e) {
+      throw new IllegalStateException("Failed to initialize HadoopStorageProvider", e);
+    }
+  }
+}

parquet-common/src/main/java/org/apache/parquet/storage/StorageProvider.java

@@ -0,0 +1,69 @@
+/*
+ *  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 org.apache.parquet.storage;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+
+/**
+ * Simple abstraction for file IO that allows Parquet components to work with
+ * different storage back-ends (NIO, Hadoop, cloud SDKs, etc.) without taking
+ * an explicit dependency on the back-end libraries.
+ *
+ * <p>The interface purposefully exposes a very small surface – just the
+ * operations currently needed by the Parquet code we intend to decouple from
+ * Hadoop.  Additional methods can be added incrementally as other areas are
+ * ported.</p>
+ *
+ * <p>This interface lives in the <code>parquet-common</code> module so that it
+ * can be referenced by any other module without creating additional coupling
+ * between them.</p>
+ */
+public interface StorageProvider {
+
+  /**
+   * Opens the given path for reading.
+   *
+   * @param path fully-qualified file path (implementation specific semantics)
+   * @return an InputStream that must be closed by the caller
+   */
+  InputStream openForRead(String path) throws IOException;
+
+  /**
+   * Opens the given path for writing. If the file already exists the behaviour
+   * depends on the overwrite flag.
+   *
+   * @param path fully-qualified file path
+   * @param overwrite  whether an existing file should be replaced
+   * @return an OutputStream that must be closed by the caller
+   */
+  OutputStream openForWrite(String path, boolean overwrite) throws IOException;
+
+  /**
+   * Deletes the file at path if it exists.
+   */
+  boolean delete(String path) throws IOException;
+
+  /**
+   * Renames the file located at source to target.
+   */
+  boolean rename(String source, String target) throws IOException;
+}

parquet-common/src/main/java/org/apache/parquet/storage/impl/NioStorageProvider.java

@@ -0,0 +1,85 @@
+/*
+ *  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 org.apache.parquet.storage.impl;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.nio.file.StandardOpenOption;
+import org.apache.parquet.storage.StorageProvider;
+
+/**
+ * A StorageProvider that relies solely on the Java NIO standard library. It
+ * can work with any FileSystem implementation available
+ * on the class-path.
+ */
+public class NioStorageProvider implements StorageProvider {
+
+  public NioStorageProvider() {}
+
+  private static Path toPath(String s) {
+    try {
+      java.net.URI uri = java.net.URI.create(s);
+      if (uri.getScheme() != null) {
+        return Paths.get(uri);
+      }
+    } catch (IllegalArgumentException ignore) {
+    }
+    return Paths.get(s);
+  }
+
+  @Override
+  public InputStream openForRead(String path) throws IOException {
+    return Files.newInputStream(toPath(path));
+  }
+
+  @Override
+  public OutputStream openForWrite(String path, boolean overwrite) throws IOException {
+    Path p = toPath(path);
+    if (overwrite) {
+      return Files.newOutputStream(
+          p, StandardOpenOption.CREATE, StandardOpenOption.TRUNCATE_EXISTING, StandardOpenOption.WRITE);
+    } else {
+      return Files.newOutputStream(p, StandardOpenOption.CREATE_NEW, StandardOpenOption.WRITE);
+    }
+  }
+
+  @Override
+  public boolean delete(String path) throws IOException {
+    return Files.deleteIfExists(toPath(path));
+  }
+
+  @Override
+  public boolean rename(String source, String target) throws IOException {
+    Path src = toPath(source);
+    Path tgt = toPath(target);
+    if (Files.exists(tgt)) return false;
+    try {
+      Files.move(src, tgt, StandardCopyOption.ATOMIC_MOVE);
+    } catch (AtomicMoveNotSupportedException e) {
+      Files.move(src, tgt);
+    }
+    return true;
+  }
+}

parquet-common/src/main/resources/META-INF/services/org.apache.parquet.storage.StorageProvider

@@ -0,0 +1,18 @@
+# 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.
+
+org.apache.parquet.storage.impl.NioStorageProvider

parquet-common/src/test/java/org/apache/parquet/storage/TestStorage.java

@@ -0,0 +1,74 @@
+/*
+ *  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 org.apache.parquet.storage;
+
+import static org.junit.Assert.*;
+
+import java.io.IOException;
+import java.net.URI;
+import org.junit.Test;
+
+public class TestStorage {
+
+  @Test
+  public void testFileSchemeReturnsNioProvider() {
+    StorageProvider provider = Storage.select(URI.create("file:///tmp/test.parquet"));
+    assertTrue(
+        "file:// should return NioStorageProvider",
+        provider instanceof org.apache.parquet.storage.impl.NioStorageProvider);
+  }
+
+  @Test
+  public void testNullUriReturnsNioProvider() {
+    StorageProvider provider = Storage.select(null);
+    assertTrue(
+        "null URI should return NioStorageProvider",
+        provider instanceof org.apache.parquet.storage.impl.NioStorageProvider);
+  }
+
+  @Test
+  public void testRelativePathReturnsNioProvider() {
+    StorageProvider provider = Storage.select(URI.create("relative/path"));
+    assertTrue(
+        "relative path should return NioStorageProvider",
+        provider instanceof org.apache.parquet.storage.impl.NioStorageProvider);
+  }
+
+  @Test
+  public void testHdfsSchemeReturnsHadoopProvider() {
+    StorageProvider provider = Storage.select(URI.create("hdfs://namenode:8020/test.parquet"));
+    assertNotNull("Should return a provider", provider);
+  }
+
+  @Test
+  public void testUnknownSchemeReturnsNioProvider() {
+    StorageProvider provider = Storage.select(URI.create("s3://bucket/test.parquet"));
+    assertTrue(
+        "unknown scheme should return NioStorageProvider",
+        provider instanceof org.apache.parquet.storage.impl.NioStorageProvider);
+  }
+
+  @Test
+  public void testNioProviderBasicOperations() throws IOException {
+    StorageProvider provider = Storage.select(URI.create("file:///tmp/test.parquet"));
+
+    assertTrue(provider instanceof org.apache.parquet.storage.impl.NioStorageProvider);
+  }
+}

parquet-hadoop/src/main/java/org/apache/parquet/storage/impl/hadoop/HadoopStorageProvider.java

@@ -0,0 +1,77 @@
+/*
+ *  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 org.apache.parquet.storage.impl.hadoop;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import org.apache.hadoop.conf.Configuration;
+import org.apache.hadoop.fs.FSDataInputStream;
+import org.apache.hadoop.fs.FSDataOutputStream;
+import org.apache.hadoop.fs.FileSystem;
+import org.apache.hadoop.fs.Path;
+import org.apache.parquet.storage.StorageProvider;
+
+/**
+ * Hadoop-backed implementation of {@link StorageProvider}. Lives in the
+ * parquet-hadoop module, under the same {@code org.apache.parquet.storage.impl}
+ * hierarchy as other providers.
+ */
+public class HadoopStorageProvider implements StorageProvider {
+
+  private final FileSystem fs;
+
+  /**
+   * Uses default Hadoop Configuration.
+   */
+  public HadoopStorageProvider() throws IOException {
+    this(new Configuration());
+  }
+
+  public HadoopStorageProvider(Configuration conf) throws IOException {
+    this.fs = FileSystem.get(conf);
+  }
+
+  @Override
+  public InputStream openForRead(String path) throws IOException {
+    Path p = new Path(path);
+    FSDataInputStream in = fs.open(p);
+    // Deliberately return the Hadoop stream as InputStream; callers should
+    // not rely on Hadoop-specific methods.
+    return in;
+  }
+
+  @Override
+  public OutputStream openForWrite(String path, boolean overwrite) throws IOException {
+    Path p = new Path(path);
+    FSDataOutputStream out = fs.create(p, overwrite);
+    return out;
+  }
+
+  @Override
+  public boolean delete(String path) throws IOException {
+    return fs.delete(new Path(path), false);
+  }
+
+  @Override
+  public boolean rename(String source, String target) throws IOException {
+    return fs.rename(new Path(source), new Path(target));
+  }
+}