| /* |
| * 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.hadoop.fs.s3a.prefetch; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import org.apache.hadoop.fs.impl.prefetch.BlockData; |
| import org.apache.hadoop.fs.impl.prefetch.BlockManager; |
| import org.apache.hadoop.fs.impl.prefetch.Validate; |
| |
| /** |
| * Provides read access to S3 file one block at a time. |
| * |
| * A naive implementation of a {@code BlockManager} that provides no prefetching or caching. |
| * Useful baseline for comparing performance difference against {@code S3ACachingBlockManager}. |
| */ |
| public class S3ABlockManager extends BlockManager { |
| |
| /** |
| * Reader that reads from S3 file. |
| */ |
| private final S3ARemoteObjectReader reader; |
| |
| /** |
| * Constructs an instance of {@code S3ABlockManager}. |
| * |
| * @param reader a reader that reads from S3 file. |
| * @param blockData information about each block of the S3 file. |
| * |
| * @throws IllegalArgumentException if reader is null. |
| * @throws IllegalArgumentException if blockData is null. |
| */ |
| public S3ABlockManager(S3ARemoteObjectReader reader, BlockData blockData) { |
| super(blockData); |
| |
| Validate.checkNotNull(reader, "reader"); |
| |
| this.reader = reader; |
| } |
| |
| /** |
| * Reads into the given {@code buffer} {@code size} bytes from the underlying file |
| * starting at {@code startOffset}. |
| * |
| * @param buffer the buffer to read data in to. |
| * @param startOffset the offset at which reading starts. |
| * @param size the number bytes to read. |
| * @return number of bytes read. |
| */ |
| @Override |
| public int read(ByteBuffer buffer, long startOffset, int size) |
| throws IOException { |
| return reader.read(buffer, startOffset, size); |
| } |
| |
| @Override |
| public void close() { |
| reader.close(); |
| } |
| } |