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/**
* 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.protocol;
import java.io.DataInput;
import java.io.DataOutput;
import java.io.IOException;
import org.apache.hadoop.classification.InterfaceAudience;
import org.apache.hadoop.classification.InterfaceStability;
import org.apache.hadoop.hdfs.protocol.Block;
import org.apache.hadoop.io.Text;
import org.apache.hadoop.io.Writable;
import org.apache.hadoop.io.WritableUtils;
/** A class to implement an array of BlockLocations
* It provide efficient customized serialization/deserialization methods
* in stead of using the default array (de)serialization provided by RPC
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public class BlocksWithLocations implements Writable {
/**
* A class to keep track of a block and its locations
*/
@InterfaceAudience.Private
@InterfaceStability.Evolving
public static class BlockWithLocations implements Writable {
Block block;
String datanodeIDs[];
/** default constructor */
public BlockWithLocations() {
block = new Block();
datanodeIDs = null;
}
/** constructor */
public BlockWithLocations(Block b, String[] datanodes) {
block = b;
datanodeIDs = datanodes;
}
/** get the block */
public Block getBlock() {
return block;
}
/** get the block's locations */
public String[] getDatanodes() {
return datanodeIDs;
}
/** deserialization method */
public void readFields(DataInput in) throws IOException {
block.readFields(in);
int len = WritableUtils.readVInt(in); // variable length integer
datanodeIDs = new String[len];
for(int i=0; i