1 package org.apache.maven.shared.dependency.tree;
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.Iterator;
23 import java.util.NoSuchElementException;
24 import java.util.Stack;
25
26 /**
27 * {@link Iterator} for {@link DependencyNode} implementing a traversal from leaves to root.
28 *
29 * TODO {@link #DependencyTreeInverseIterator(DependencyNode)} is costly,
30 * a better implementation would move the cost to {@link #next()}
31 *
32 * @author <a href="mailto:carlos@apache.org">Carlos Sanchez</a>
33 * @version $Id: DependencyTreeInverseIterator.java 1100703 2011-05-08 08:27:33Z hboutemy $
34 */
35 public class DependencyTreeInverseIterator
36 implements Iterator<DependencyNode>
37 {
38 private Stack<DependencyNode> nodesToProcess = new Stack<DependencyNode>();
39
40 public DependencyTreeInverseIterator( DependencyNode rootNode )
41 {
42 DependencyTreePreorderIterator it = new DependencyTreePreorderIterator( rootNode );
43 while ( it.hasNext() )
44 {
45 nodesToProcess.push( it.next() );
46 }
47 }
48
49 public boolean hasNext()
50 {
51 return !nodesToProcess.isEmpty();
52 }
53
54 public DependencyNode next()
55 {
56 if ( !hasNext() )
57 {
58 throw new NoSuchElementException();
59 }
60 return nodesToProcess.pop();
61 }
62
63 /**
64 * @throws UnsupportedOperationException
65 */
66 public void remove()
67 {
68 throw new UnsupportedOperationException();
69 }
70 }