001/* 002 * Licensed to the Apache Software Foundation (ASF) under one 003 * or more contributor license agreements. See the NOTICE file 004 * distributed with this work for additional information 005 * regarding copyright ownership. The ASF licenses this file 006 * to you under the Apache License, Version 2.0 (the 007 * "License"); you may not use this file except in compliance 008 * with the License. You may obtain a copy of the License at 009 * 010 * http://www.apache.org/licenses/LICENSE-2.0 011 * 012 * Unless required by applicable law or agreed to in writing, 013 * software distributed under the License is distributed on an 014 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY 015 * KIND, either express or implied. See the License for the 016 * specific language governing permissions and limitations 017 * under the License. 018 */ 019package org.eclipse.aether.util.graph.version; 020 021import java.util.Arrays; 022import java.util.Collection; 023 024import org.eclipse.aether.RepositoryException; 025import org.eclipse.aether.collection.DependencyCollectionContext; 026import org.eclipse.aether.collection.VersionFilter; 027 028/** 029 * A version filter that combines multiple version filters into a chain where each filter gets invoked one after the 030 * other, thereby accumulating their filtering effects. 031 */ 032public final class ChainedVersionFilter implements VersionFilter { 033 034 private final VersionFilter[] filters; 035 036 private int hashCode; 037 038 /** 039 * Chains the specified version filters. 040 * 041 * @param filter1 The first version filter, may be {@code null}. 042 * @param filter2 The second version filter, may be {@code null}. 043 * @return The chained version filter or {@code null} if both input filters are {@code null}. 044 */ 045 public static VersionFilter newInstance(VersionFilter filter1, VersionFilter filter2) { 046 if (filter1 == null) { 047 return filter2; 048 } 049 if (filter2 == null) { 050 return filter1; 051 } 052 return new ChainedVersionFilter(new VersionFilter[] {filter1, filter2}); 053 } 054 055 /** 056 * Chains the specified version filters. 057 * 058 * @param filters The version filters to chain, must not be {@code null} or contain {@code null}. 059 * @return The chained version filter or {@code null} if the input array is empty. 060 */ 061 public static VersionFilter newInstance(VersionFilter... filters) { 062 if (filters.length <= 1) { 063 if (filters.length <= 0) { 064 return null; 065 } 066 return filters[0]; 067 } 068 return new ChainedVersionFilter(filters.clone()); 069 } 070 071 /** 072 * Chains the specified version filters. 073 * 074 * @param filters The version filters to chain, must not be {@code null} or contain {@code null}. 075 * @return The chained version filter or {@code null} if the input collection is empty. 076 */ 077 public static VersionFilter newInstance(Collection<? extends VersionFilter> filters) { 078 if (filters.size() <= 1) { 079 if (filters.isEmpty()) { 080 return null; 081 } 082 return filters.iterator().next(); 083 } 084 return new ChainedVersionFilter(filters.toArray(new VersionFilter[0])); 085 } 086 087 private ChainedVersionFilter(VersionFilter[] filters) { 088 this.filters = filters; 089 } 090 091 public void filterVersions(VersionFilterContext context) throws RepositoryException { 092 for (int i = 0, n = filters.length; i < n && context.getCount() > 0; i++) { 093 filters[i].filterVersions(context); 094 } 095 } 096 097 public VersionFilter deriveChildFilter(DependencyCollectionContext context) { 098 VersionFilter[] children = null; 099 int removed = 0; 100 for (int i = 0, n = filters.length; i < n; i++) { 101 VersionFilter child = filters[i].deriveChildFilter(context); 102 if (children != null) { 103 children[i - removed] = child; 104 } else if (child != filters[i]) { 105 children = new VersionFilter[filters.length]; 106 System.arraycopy(filters, 0, children, 0, i); 107 children[i - removed] = child; 108 } 109 if (child == null) { 110 removed++; 111 } 112 } 113 if (children == null) { 114 return this; 115 } 116 if (removed > 0) { 117 int count = filters.length - removed; 118 if (count <= 0) { 119 return null; 120 } 121 if (count == 1) { 122 return children[0]; 123 } 124 VersionFilter[] tmp = new VersionFilter[count]; 125 System.arraycopy(children, 0, tmp, 0, count); 126 children = tmp; 127 } 128 return new ChainedVersionFilter(children); 129 } 130 131 @Override 132 public boolean equals(Object obj) { 133 if (this == obj) { 134 return true; 135 } else if (null == obj || !getClass().equals(obj.getClass())) { 136 return false; 137 } 138 139 ChainedVersionFilter that = (ChainedVersionFilter) obj; 140 return Arrays.equals(filters, that.filters); 141 } 142 143 @Override 144 public int hashCode() { 145 if (hashCode == 0) { 146 int hash = getClass().hashCode(); 147 hash = hash * 31 + Arrays.hashCode(filters); 148 hashCode = hash; 149 } 150 return hashCode; 151 } 152}