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.plugins.dependency.tree;
20
21 import java.io.Writer;
22 import java.util.ArrayList;
23 import java.util.List;
24
25 import org.apache.maven.shared.dependency.graph.DependencyNode;
26 import org.apache.maven.shared.dependency.graph.traversal.DependencyNodeVisitor;
27
28 /**
29 * A dependency node visitor that serializes visited nodes to a writer using the
30 * <a href="https://en.wikipedia.org/wiki/Trivial_Graph_Format">TGF format</a>.
31 *
32 * @author <a href="mailto:jerome.creignou@gmail.com">Jerome Creignou</a>
33 * @since 2.1
34 */
35 public class TGFDependencyNodeVisitor extends AbstractSerializingVisitor implements DependencyNodeVisitor {
36
37 /**
38 * Utiity class to write an Edge.
39 *
40 * @author <a href="mailto:jerome.creignou@gmail.com">Jerome Creignou</a>
41 */
42 static final class EdgeAppender {
43 /**
44 * Edge start.
45 */
46 private final DependencyNode from;
47
48 /**
49 * Edge end.
50 */
51 private final DependencyNode to;
52
53 /**
54 * Edge label. (optional)
55 */
56 private final String label;
57
58 /**
59 * Build a new EdgeAppender.
60 *
61 * @param from edge start.
62 * @param to edge end
63 * @param label optional label.
64 */
65 EdgeAppender(DependencyNode from, DependencyNode to, String label) {
66 super();
67 this.from = from;
68 this.to = to;
69 this.label = label;
70 }
71
72 /**
73 * build a string representing the edge.
74 */
75 @Override
76 public String toString() {
77 StringBuilder result = new StringBuilder(generateId(from));
78 result.append(' ').append(generateId(to));
79 if (label != null) {
80 result.append(' ').append(label);
81 }
82 return result.toString();
83 }
84 }
85
86 /**
87 * List of edges.
88 */
89 private final List<EdgeAppender> edges = new ArrayList<>();
90
91 /**
92 * Constructor.
93 *
94 * @param writer the writer to write to.
95 */
96 public TGFDependencyNodeVisitor(Writer writer) {
97 super(writer);
98 }
99
100 /**
101 * {@inheritDoc}
102 */
103 @Override
104 public boolean endVisit(DependencyNode node) {
105 if (node.getParent() == null || node.getParent() == node) {
106 // dump edges on last node endVisit
107 writer.println("#");
108 for (EdgeAppender edge : edges) {
109 writer.println(edge.toString());
110 }
111 } else {
112 DependencyNode p = node.getParent();
113 // using scope as edge label.
114 edges.add(new EdgeAppender(p, node, node.getArtifact().getScope()));
115 }
116 return true;
117 }
118
119 /**
120 * {@inheritDoc}
121 */
122 @Override
123 public boolean visit(DependencyNode node) {
124 // write node
125 writer.write(generateId(node));
126 writer.write(" ");
127 writer.println(node.toNodeString());
128 return true;
129 }
130
131 /**
132 * Generate a unique id from a DependencyNode.
133 * <p>
134 * Current implementation is rather simple and uses hashcode.
135 * </p>
136 *
137 * @param node the DependencyNode to use.
138 * @return the unique id.
139 */
140 private static String generateId(DependencyNode node) {
141 return String.valueOf(node.hashCode());
142 }
143 }