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     */
018    package org.apache.hadoop.hdfs.server.blockmanagement;
019    
020    public class BlockPlacementStatusDefault implements BlockPlacementStatus {
021    
022      private int requiredRacks = 0;
023      private int currentRacks = 0;
024      
025      public BlockPlacementStatusDefault(int currentRacks, int requiredRacks){
026        this.requiredRacks = requiredRacks;
027        this.currentRacks = currentRacks;
028      }
029      
030      @Override
031      public boolean isPlacementPolicySatisfied() {
032        return requiredRacks <= currentRacks;
033      }
034    
035      @Override
036      public String getErrorDescription() {
037        if (isPlacementPolicySatisfied()) {
038          return null;
039        }
040        return "Block should be additionally replicated on " + 
041            (requiredRacks - currentRacks) + " more rack(s).";
042      }
043    
044    }