1 package org.eclipse.aether.util.graph.transformer;
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 org.eclipse.aether.RepositoryException;
23 import org.eclipse.aether.collection.DependencyGraphTransformationContext;
24 import org.eclipse.aether.collection.DependencyGraphTransformer;
25 import org.eclipse.aether.graph.DependencyNode;
26
27 import static java.util.Objects.requireNonNull;
28
29 /**
30 * A dependency graph transformer that chains other transformers.
31 */
32 public final class ChainedDependencyGraphTransformer
33 implements DependencyGraphTransformer
34 {
35
36 private final DependencyGraphTransformer[] transformers;
37
38 /**
39 * Creates a new transformer that chains the specified transformers.
40 *
41 * @param transformers The transformers to chain, may be {@code null} or empty.
42 */
43 public ChainedDependencyGraphTransformer( DependencyGraphTransformer... transformers )
44 {
45 if ( transformers == null )
46 {
47 this.transformers = new DependencyGraphTransformer[0];
48 }
49 else
50 {
51 this.transformers = transformers;
52 }
53 }
54
55 /**
56 * Creates a new transformer that chains the specified transformers or simply returns one of them if the other one
57 * is {@code null}.
58 *
59 * @param transformer1 The first transformer of the chain, may be {@code null}.
60 * @param transformer2 The second transformer of the chain, may be {@code null}.
61 * @return The chained transformer or {@code null} if both input transformers are {@code null}.
62 */
63 public static DependencyGraphTransformer newInstance( DependencyGraphTransformer transformer1,
64 DependencyGraphTransformer transformer2 )
65 {
66 if ( transformer1 == null )
67 {
68 return transformer2;
69 }
70 else if ( transformer2 == null )
71 {
72 return transformer1;
73 }
74 return new ChainedDependencyGraphTransformer( transformer1, transformer2 );
75 }
76
77 public DependencyNode transformGraph( DependencyNode node, DependencyGraphTransformationContext context )
78 throws RepositoryException
79 {
80 requireNonNull( node, "node cannot be null" );
81 requireNonNull( context, "context cannot be null" );
82 for ( DependencyGraphTransformer transformer : transformers )
83 {
84 node = transformer.transformGraph( node, context );
85 }
86 return node;
87 }
88
89 }