/** * Copyright 2005 The Apache Software Foundation * * Licensed 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.dfs;import org.apache.hadoop.io.*;import java.io.*;/**************************************************** * A LocatedBlock is a pair of Block, DatanodeInfo[] * objects.  It tells where to find a Block. *  * @author Michael Cafarella ****************************************************/class LocatedBlock implements Writable {    static {                                      // register a ctor      WritableFactories.setFactory        (LocatedBlock.class,         new WritableFactory() {           public Writable newInstance() { return new LocatedBlock(); }         });    }    Block b;    DatanodeInfo locs[];    /**     */    public LocatedBlock() {        this.b = new Block();        this.locs = new DatanodeInfo[0];    }    /**     */    public LocatedBlock(Block b, DatanodeInfo[] locs) {        this.b = b;        this.locs = locs;    }    /**     */    public Block getBlock() {        return b;    }    /**     */    DatanodeInfo[] getLocations() {        return locs;    }    ///////////////////////////////////////////    // Writable    ///////////////////////////////////////////    public void write(DataOutput out) throws IOException {        b.write(out);        out.writeInt(locs.length);        for (int i = 0; i < locs.length; i++) {            locs[i].write(out);        }    }    public void readFields(DataInput in) throws IOException {        this.b = new Block();        b.readFields(in);        int count = in.readInt();        this.locs = new DatanodeInfo[count];        for (int i = 0; i < locs.length; i++) {            locs[i] = new DatanodeInfo();            locs[i].readFields(in);        }    }}