1 package org.apache.maven.shared.runtime;
2
3 /*
4 * Licensed to the Apache Software Foundation (ASF) under one
5 * or more contributor license agreements. See the NOTICE file
6 * distributed with this work for additional information
7 * regarding copyright ownership. The ASF licenses this file
8 * to you under the Apache License, Version 2.0 (the
9 * "License"); you may not use this file except in compliance
10 * with the License. You may obtain a copy of the License at
11 *
12 * http://www.apache.org/licenses/LICENSE-2.0
13 *
14 * Unless required by applicable law or agreed to in writing,
15 * software distributed under the License is distributed on an
16 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
17 * KIND, either express or implied. See the License for the
18 * specific language governing permissions and limitations
19 * under the License.
20 */
21
22 import java.util.Enumeration;
23
24 /**
25 * Enumeration that spans two other enumerations.
26 *
27 * @author <a href="mailto:markh@apache.org">Mark Hobson</a>
28 * @version $Id: CompositeEnumeration.java 831910 2009-11-02 15:05:33Z markh $
29 * @param <T>
30 * the element type of this enumeration
31 */
32 public class CompositeEnumeration<T> implements Enumeration<T>
33 {
34 // fields -------------------------------------------------------------
35
36 private final Enumeration<T> enumeration1;
37
38 private final Enumeration<T> enumeration2;
39
40 // constructors -------------------------------------------------------
41
42 public CompositeEnumeration( Enumeration<T> enumeration1, Enumeration<T> enumeration2 )
43 {
44 this.enumeration1 = enumeration1;
45 this.enumeration2 = enumeration2;
46 }
47
48 // Enumeration methods ------------------------------------------------
49
50 /**
51 * {@inheritDoc}
52 */
53 public boolean hasMoreElements()
54 {
55 return enumeration1.hasMoreElements() || enumeration2.hasMoreElements();
56 }
57
58 /**
59 * {@inheritDoc}
60 */
61 public T nextElement()
62 {
63 T element;
64
65 if ( enumeration1.hasMoreElements() )
66 {
67 element = enumeration1.nextElement();
68 }
69 else
70 {
71 element = enumeration2.nextElement();
72 }
73
74 return element;
75 }
76 }