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,
13 * software distributed under the License is distributed on an
14 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
15 * KIND, either express or implied. See the License for the
16 * specific language governing permissions and limitations
17 * under the License.
18 */
19 package org.apache.maven.enforcer.rules.utils;
20
21 import java.util.HashMap;
22 import java.util.Map;
23 import java.util.Stack;
24
25 import org.eclipse.aether.graph.DependencyNode;
26 import org.eclipse.aether.graph.DependencyVisitor;
27
28 /**
29 * A {@link DependencyVisitor} building a map of parent nodes
30 */
31 public class ParentsVisitor implements DependencyVisitor, ParentNodeProvider {
32
33 private final Map<DependencyNode, DependencyNode> parents = new HashMap<>();
34 private final Stack<DependencyNode> parentStack = new Stack<>();
35
36 @Override
37 public DependencyNode getParent(DependencyNode node) {
38 return parents.get(node);
39 }
40
41 @Override
42 public boolean visitEnter(DependencyNode node) {
43 parents.put(node, parentStack.isEmpty() ? null : parentStack.peek());
44 parentStack.push(node);
45 return true;
46 }
47
48 @Override
49 public boolean visitLeave(DependencyNode node) {
50 parentStack.pop();
51 return true;
52 }
53 }