001package org.eclipse.aether.util.graph.transformer; 002 003/* 004 * Licensed to the Apache Software Foundation (ASF) under one 005 * or more contributor license agreements. See the NOTICE file 006 * distributed with this work for additional information 007 * regarding copyright ownership. The ASF licenses this file 008 * to you under the Apache License, Version 2.0 (the 009 * "License"); you may not use this file except in compliance 010 * with the License. You may obtain a copy of the License at 011 * 012 * http://www.apache.org/licenses/LICENSE-2.0 013 * 014 * Unless required by applicable law or agreed to in writing, 015 * software distributed under the License is distributed on an 016 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 017 * KIND, either express or implied. See the License for the 018 * specific language governing permissions and limitations 019 * under the License. 020 */ 021 022import org.eclipse.aether.RepositoryException; 023import org.eclipse.aether.collection.DependencyGraphTransformationContext; 024import org.eclipse.aether.collection.DependencyGraphTransformer; 025import org.eclipse.aether.graph.DependencyNode; 026 027import static java.util.Objects.requireNonNull; 028 029/** 030 * A dependency graph transformer that chains other transformers. 031 */ 032public final class ChainedDependencyGraphTransformer 033 implements DependencyGraphTransformer 034{ 035 036 private final DependencyGraphTransformer[] transformers; 037 038 /** 039 * Creates a new transformer that chains the specified transformers. 040 * 041 * @param transformers The transformers to chain, may be {@code null} or empty. 042 */ 043 public ChainedDependencyGraphTransformer( DependencyGraphTransformer... transformers ) 044 { 045 if ( transformers == null ) 046 { 047 this.transformers = new DependencyGraphTransformer[0]; 048 } 049 else 050 { 051 this.transformers = transformers; 052 } 053 } 054 055 /** 056 * Creates a new transformer that chains the specified transformers or simply returns one of them if the other one 057 * is {@code null}. 058 * 059 * @param transformer1 The first transformer of the chain, may be {@code null}. 060 * @param transformer2 The second transformer of the chain, may be {@code null}. 061 * @return The chained transformer or {@code null} if both input transformers are {@code null}. 062 */ 063 public static DependencyGraphTransformer newInstance( DependencyGraphTransformer transformer1, 064 DependencyGraphTransformer transformer2 ) 065 { 066 if ( transformer1 == null ) 067 { 068 return transformer2; 069 } 070 else if ( transformer2 == null ) 071 { 072 return transformer1; 073 } 074 return new ChainedDependencyGraphTransformer( transformer1, transformer2 ); 075 } 076 077 public DependencyNode transformGraph( DependencyNode node, DependencyGraphTransformationContext context ) 078 throws RepositoryException 079 { 080 requireNonNull( node, "node cannot be null" ); 081 requireNonNull( context, "context cannot be null" ); 082 for ( DependencyGraphTransformer transformer : transformers ) 083 { 084 node = transformer.transformGraph( node, context ); 085 } 086 return node; 087 } 088 089}