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IteratorToReaderWrapper 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  
19  package org.apache.giraph.io.iterables;
20  
21  import java.util.Iterator;
22  
23  /**
24   * Wraps {@link Iterator} into object which provides iteration like in
25   * {@link org.apache.giraph.io.VertexReader} or
26   * {@link org.apache.giraph.io.EdgeReader}
27   *
28   * @param <T>
29   */
30  public class IteratorToReaderWrapper<T> {
31    /** Wrapped iterator */
32    private Iterator<T> iterator;
33    /** Current object */
34    private T currentObject = null;
35  
36    /**
37     * Constructor
38     *
39     * @param iterator Iterator to wrap
40     */
41    public IteratorToReaderWrapper(Iterator<T> iterator) {
42      this.iterator = iterator;
43    }
44  
45    /**
46     * Read next object
47     *
48     * @return False iff there are no more objects
49     */
50    public boolean nextObject() {
51      boolean hasNext = iterator.hasNext();
52      if (hasNext) {
53        currentObject = iterator.next();
54      } else {
55        currentObject = null;
56      }
57      return hasNext;
58    }
59  
60    /**
61     * Get the current object
62     *
63     * @return Current object
64     */
65    public T getCurrentObject() {
66      return currentObject;
67    }
68  }