This project has retired. For details please refer to its Attic page.
AndReduce xref
View Javadoc

1   /*
2    * Licensed to the Apache Software Foundation (ASF) under one
3    * or more contributor license agreements.  See the NOTICE file
4    * distributed with this work for additional information
5    * regarding copyright ownership.  The ASF licenses this file
6    * to you under the Apache License, Version 2.0 (the
7    * "License"); you may not use this file except in compliance
8    * with the License.  You may obtain a copy of the License at
9    *
10   *     http://www.apache.org/licenses/LICENSE-2.0
11   *
12   * Unless required by applicable law or agreed to in writing, software
13   * distributed under the License is distributed on an "AS IS" BASIS,
14   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
15   * See the License for the specific language governing permissions and
16   * limitations under the License.
17   */
18  package org.apache.giraph.reducers.impl;
19  
20  import java.io.DataInput;
21  import java.io.DataOutput;
22  import java.io.IOException;
23  
24  import org.apache.giraph.reducers.ReduceSameTypeOperation;
25  import org.apache.hadoop.io.BooleanWritable;
26  
27  /**
28   *
29   * ReduceOperation for calculating the AND function over boolean values.
30   * The default value when nothing is aggregated is true.
31   *
32   */
33  public class AndReduce extends ReduceSameTypeOperation<BooleanWritable> {
34    /** Instance */
35    public static final AndReduce INSTANCE = new AndReduce();
36  
37    @Override
38    public BooleanWritable createInitialValue() {
39      return new BooleanWritable(true);
40    }
41  
42    @Override
43    public BooleanWritable reduce(
44        BooleanWritable curValue, BooleanWritable valueToReduce) {
45      curValue.set(curValue.get() && valueToReduce.get());
46      return curValue;
47    }
48  
49    @Override
50    public void write(DataOutput out) throws IOException {
51    }
52  
53    @Override
54    public void readFields(DataInput in) throws IOException {
55    }
56  }