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.graph;
20
21 import java.util.List;
22
23 /**
24 * A cycle within a dependency graph, that is a sequence of dependencies d_1, d_2, ..., d_n where d_1 and d_n have the
25 * same versionless coordinates. In more practical terms, a cycle occurs when a project directly or indirectly depends
26 * on its own output artifact.
27 *
28 * @noimplement This interface is not intended to be implemented by clients.
29 * @noextend This interface is not intended to be extended by clients.
30 */
31 public interface DependencyCycle {
32
33 /**
34 * Gets the dependencies that lead to the first dependency on the cycle, starting from the root of the dependency
35 * graph.
36 *
37 * @return The (read-only) sequence of dependencies that precedes the cycle in the graph, potentially empty but
38 * never {@code null}.
39 */
40 List<Dependency> getPrecedingDependencies();
41
42 /**
43 * Gets the dependencies that actually form the cycle. For example, a -> b -> c -> a, i.e. the last
44 * dependency in this sequence duplicates the first element and closes the cycle. Hence the length of the cycle is
45 * the size of the returned sequence minus 1.
46 *
47 * @return The (read-only) sequence of dependencies that forms the cycle, never {@code null}.
48 */
49 List<Dependency> getCyclicDependencies();
50 }