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.eclipse.aether.internal.impl.collect.df;
20
21 import java.util.ArrayList;
22
23 import org.eclipse.aether.graph.DependencyNode;
24
25 /**
26 * Internal helper for {@link DfDependencyCollector}. Originally (pre-1.8.0) this same class was located a
27 * package higher.
28 *
29 * @since 1.8.0
30 */
31 final class NodeStack {
32
33 @SuppressWarnings({"checkstyle:magicnumber"})
34 // CHECKSTYLE_OFF: MagicNumber
35 ArrayList<DependencyNode> nodes = new ArrayList<>(96);
36 // CHECKSTYLE_ON: MagicNumber
37
38 public DependencyNode top() {
39 if (nodes.isEmpty()) {
40 throw new IllegalStateException("stack empty");
41 }
42 return nodes.get(nodes.size() - 1);
43 }
44
45 public void push(DependencyNode node) {
46 nodes.add(node);
47 }
48
49 public void pop() {
50 if (nodes.isEmpty()) {
51 throw new IllegalStateException("stack empty");
52 }
53 nodes.remove(nodes.size() - 1);
54 }
55
56 public int size() {
57 return nodes.size();
58 }
59
60 public DependencyNode get(int index) {
61 return nodes.get(index);
62 }
63
64 @Override
65 public String toString() {
66 return nodes.toString();
67 }
68 }