Java tutorial
/** * 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.hdfs.server.datanode; import java.io.DataInput; import java.io.DataOutput; import java.io.DataOutputStream; import java.io.File; import java.io.FileOutputStream; import java.io.IOException; import java.io.InterruptedIOException; import java.util.List; import java.util.Map; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.hdfs.protocol.Block; import org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolume; import org.apache.hadoop.hdfs.server.datanode.FSDataset.FSVolumeSet; import org.apache.hadoop.io.IntWritable; import org.apache.hadoop.io.Writable; /** * The data structure used to stream block CRC information of one block from and * to a local file. */ class BlockCrcInfoWritable implements Writable { static int LATEST_BLOCK_CRC_FILE_VERSION = 1; long blockId; long blockGenStamp; int blockCrc; BlockCrcInfoWritable() { } void set(long blockId, long blockGenStamp, int blockCrc) { this.blockId = blockId; this.blockGenStamp = blockGenStamp; this.blockCrc = blockCrc; } @Override public void write(DataOutput out) throws IOException { out.writeLong(blockId); out.writeLong(blockGenStamp); out.writeInt(blockCrc); } @Override public void readFields(DataInput in) throws IOException { this.blockId = in.readLong(); this.blockGenStamp = in.readLong(); this.blockCrc = in.readInt(); } }