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SmallDirectedForestGraphInit xref
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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.block_app.test_setup.graphs;
19  
20  import org.apache.giraph.block_app.test_setup.NumericTestGraph;
21  import org.apache.giraph.block_app.test_setup.TestGraphModifier;
22  import org.apache.giraph.function.Supplier;
23  import org.apache.hadoop.io.Writable;
24  import org.apache.hadoop.io.WritableComparable;
25  
26  
27  /**
28   * Create a directed forest that looks like:
29   *
30   *   0      4     6
31   *  / \     |    / \
32   * 1   2    5   7   8
33   *     |
34   *     3
35   *
36   * Edges are directed from top to bottom.
37   * Vertices with no edges are created.
38   *
39   * @param <I> Vertex id type
40   * @param <V> Vertex value type
41   * @param <E> Edge value type
42   */
43  public class SmallDirectedForestGraphInit<I extends WritableComparable,
44      V extends Writable, E extends Writable>
45      implements TestGraphModifier<I, V, E> {
46  
47    private final Supplier<E> edgeSupplier;
48  
49    public SmallDirectedForestGraphInit() {
50      this(null);
51    }
52  
53    public SmallDirectedForestGraphInit(Supplier<E> edgeSupplier) {
54      this.edgeSupplier = edgeSupplier;
55    }
56  
57    @Override
58    public void modifyGraph(NumericTestGraph<I, V, E> graph) {
59      graph.addEdge(0, 1, createEdgeValue());
60      graph.addEdge(0, 2, createEdgeValue());
61      graph.addEdge(2, 3, createEdgeValue());
62      graph.addEdge(4, 5, createEdgeValue());
63      graph.addEdge(6, 7, createEdgeValue());
64      graph.addEdge(6, 8, createEdgeValue());
65  
66      graph.addVertex(1);
67      graph.addVertex(3);
68      graph.addVertex(5);
69      graph.addVertex(7);
70      graph.addVertex(8);
71    }
72  
73    private E createEdgeValue() {
74      return edgeSupplier != null ? edgeSupplier.get() : null;
75    }
76  }