| package org.eclipse.aether.util.graph.traverser; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.LinkedHashSet; |
| import java.util.Set; |
| |
| import org.eclipse.aether.collection.DependencyCollectionContext; |
| import org.eclipse.aether.collection.DependencyTraverser; |
| import org.eclipse.aether.graph.Dependency; |
| |
| /** |
| * A dependency traverser that combines zero or more other traversers using a logical {@code AND}. The resulting |
| * traverser enables processing of child dependencies if and only if all constituent traversers request traversal. |
| */ |
| public final class AndDependencyTraverser |
| implements DependencyTraverser |
| { |
| |
| private final Set<? extends DependencyTraverser> traversers; |
| |
| private int hashCode; |
| |
| /** |
| * Creates a new traverser from the specified traversers. Prefer |
| * {@link #newInstance(DependencyTraverser, DependencyTraverser)} if any of the input traversers might be |
| * {@code null}. |
| * |
| * @param traversers The traversers to combine, may be {@code null} but must not contain {@code null} elements. |
| */ |
| public AndDependencyTraverser( DependencyTraverser... traversers ) |
| { |
| if ( traversers != null && traversers.length > 0 ) |
| { |
| this.traversers = new LinkedHashSet<DependencyTraverser>( Arrays.asList( traversers ) ); |
| } |
| else |
| { |
| this.traversers = Collections.emptySet(); |
| } |
| } |
| |
| /** |
| * Creates a new traverser from the specified traversers. |
| * |
| * @param traversers The traversers to combine, may be {@code null} but must not contain {@code null} elements. |
| */ |
| public AndDependencyTraverser( Collection<? extends DependencyTraverser> traversers ) |
| { |
| if ( traversers != null && !traversers.isEmpty() ) |
| { |
| this.traversers = new LinkedHashSet<DependencyTraverser>( traversers ); |
| } |
| else |
| { |
| this.traversers = Collections.emptySet(); |
| } |
| } |
| |
| private AndDependencyTraverser( Set<DependencyTraverser> traversers ) |
| { |
| if ( traversers != null && !traversers.isEmpty() ) |
| { |
| this.traversers = traversers; |
| } |
| else |
| { |
| this.traversers = Collections.emptySet(); |
| } |
| } |
| |
| /** |
| * Creates a new traverser from the specified traversers. |
| * |
| * @param traverser1 The first traverser to combine, may be {@code null}. |
| * @param traverser2 The second traverser to combine, may be {@code null}. |
| * @return The combined traverser or {@code null} if both traversers were {@code null}. |
| */ |
| public static DependencyTraverser newInstance( DependencyTraverser traverser1, DependencyTraverser traverser2 ) |
| { |
| if ( traverser1 == null ) |
| { |
| return traverser2; |
| } |
| else if ( traverser2 == null || traverser2.equals( traverser1 ) ) |
| { |
| return traverser1; |
| } |
| return new AndDependencyTraverser( traverser1, traverser2 ); |
| } |
| |
| public boolean traverseDependency( Dependency dependency ) |
| { |
| for ( DependencyTraverser traverser : traversers ) |
| { |
| if ( !traverser.traverseDependency( dependency ) ) |
| { |
| return false; |
| } |
| } |
| return true; |
| } |
| |
| public DependencyTraverser deriveChildTraverser( DependencyCollectionContext context ) |
| { |
| int seen = 0; |
| Set<DependencyTraverser> childTraversers = null; |
| |
| for ( DependencyTraverser traverser : traversers ) |
| { |
| DependencyTraverser childTraverser = traverser.deriveChildTraverser( context ); |
| if ( childTraversers != null ) |
| { |
| if ( childTraverser != null ) |
| { |
| childTraversers.add( childTraverser ); |
| } |
| } |
| else if ( traverser != childTraverser ) |
| { |
| childTraversers = new LinkedHashSet<DependencyTraverser>(); |
| if ( seen > 0 ) |
| { |
| for ( DependencyTraverser s : traversers ) |
| { |
| if ( childTraversers.size() >= seen ) |
| { |
| break; |
| } |
| childTraversers.add( s ); |
| } |
| } |
| if ( childTraverser != null ) |
| { |
| childTraversers.add( childTraverser ); |
| } |
| } |
| else |
| { |
| seen++; |
| } |
| } |
| |
| if ( childTraversers == null ) |
| { |
| return this; |
| } |
| if ( childTraversers.size() <= 1 ) |
| { |
| if ( childTraversers.isEmpty() ) |
| { |
| return null; |
| } |
| return childTraversers.iterator().next(); |
| } |
| return new AndDependencyTraverser( childTraversers ); |
| } |
| |
| @Override |
| public boolean equals( Object obj ) |
| { |
| if ( this == obj ) |
| { |
| return true; |
| } |
| else if ( null == obj || !getClass().equals( obj.getClass() ) ) |
| { |
| return false; |
| } |
| |
| AndDependencyTraverser that = (AndDependencyTraverser) obj; |
| return traversers.equals( that.traversers ); |
| } |
| |
| @Override |
| public int hashCode() |
| { |
| if ( hashCode == 0 ) |
| { |
| int hash = 17; |
| hash = hash * 31 + traversers.hashCode(); |
| hashCode = hash; |
| } |
| return hashCode; |
| } |
| |
| } |