001/**
002 * Licensed to the Apache Software Foundation (ASF) under one
003 * or more contributor license agreements.  See the NOTICE file
004 * distributed with this work for additional information
005 * regarding copyright ownership.  The ASF licenses this file
006 * to you under the Apache License, Version 2.0 (the
007 * "License"); you may not use this file except in compliance
008 * with the License.  You may obtain a copy of the License at
009 *
010 *     http://www.apache.org/licenses/LICENSE-2.0
011 *
012 * Unless required by applicable law or agreed to in writing, software
013 * distributed under the License is distributed on an "AS IS" BASIS,
014 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
015 * See the License for the specific language governing permissions and
016 * limitations under the License.
017 */
018package org.apache.hadoop.hdfs.server.blockmanagement;
019
020import java.io.IOException;
021
022/** 
023 * This interface is used by the block manager to expose a
024 * few characteristics of a collection of Block/BlockUnderConstruction.
025 */
026public interface MutableBlockCollection extends BlockCollection {
027  /**
028   * Set the block at the given index.
029   */
030  public void setBlock(int index, BlockInfo blk);
031
032  /**
033   * Convert the last block of the collection to an under-construction block
034   * and set the locations.
035   */
036  public BlockInfoUnderConstruction setLastBlock(BlockInfo lastBlock,
037      DatanodeStorageInfo[] storages) throws IOException;
038}