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DefaultComputationFactory 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.factories;
19  
20  import org.apache.giraph.conf.GiraphConfiguration;
21  import org.apache.giraph.conf.GiraphConstants;
22  import org.apache.giraph.conf.ImmutableClassesGiraphConfiguration;
23  import org.apache.giraph.graph.Computation;
24  import org.apache.giraph.utils.ReflectionUtils;
25  import org.apache.hadoop.io.Writable;
26  import org.apache.hadoop.io.WritableComparable;
27  
28  /**
29   * Default computation factory that simply creates java computation object
30   *
31   * @param <I> Vertex ID
32   * @param <V> Vertex Value
33   * @param <E> Edge Value
34   */
35  public class DefaultComputationFactory<I extends WritableComparable,
36      V extends Writable, E extends Writable>
37      implements ComputationFactory<I, V, E, Writable, Writable> {
38    @Override
39    public void initialize(ImmutableClassesGiraphConfiguration<I, V, E> conf) {
40      // Nothing to do here
41    }
42  
43    @Override
44    public Computation<I, V, E, Writable, Writable> createComputation(
45        ImmutableClassesGiraphConfiguration<I, V, E> conf) {
46      Class<? extends Computation> klass = conf.getComputationClass();
47      return ReflectionUtils.newInstance(klass, conf);
48    }
49  
50    @Override
51    public void checkConfiguration(
52        ImmutableClassesGiraphConfiguration<I, V, E> conf) {
53      if (conf.getComputationClass() == null) {
54        throw new IllegalArgumentException("checkConfiguration: Null " +
55            GiraphConstants.COMPUTATION_CLASS.getKey());
56      }
57    }
58  
59    @Override
60    public String computationName(GiraphConfiguration conf) {
61      return conf.getComputationClass().getSimpleName();
62    }
63  }