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.Iterator; 022 023import org.eclipse.aether.collection.DependencyCollectionContext; 024import org.eclipse.aether.collection.VersionFilter; 025import org.eclipse.aether.version.Version; 026 027/** 028 * A version filter that excludes any version except the highest one. 029 */ 030public final class HighestVersionFilter implements VersionFilter { 031 private final int count; 032 033 /** 034 * Creates a new instance of this version filter. 035 */ 036 public HighestVersionFilter() { 037 this.count = 1; 038 } 039 040 /** 041 * Creates a new instance of this version filter. 042 */ 043 public HighestVersionFilter(int count) { 044 if (count < 1) { 045 throw new IllegalArgumentException("Count should be greater or equal to 1"); 046 } 047 this.count = count; 048 } 049 050 @Override 051 public void filterVersions(VersionFilterContext context) { 052 if (context.getCount() <= count) { 053 return; 054 } 055 // iterator comes in ascending order, basically we "step over" (remove) first few 056 int stepOver = context.getCount() - count; 057 Iterator<Version> it = context.iterator(); 058 while (it.hasNext()) { 059 it.next(); 060 stepOver--; 061 if (stepOver >= 0) { 062 it.remove(); 063 } 064 } 065 } 066 067 @Override 068 public VersionFilter deriveChildFilter(DependencyCollectionContext context) { 069 return this; 070 } 071 072 @Override 073 public boolean equals(Object obj) { 074 if (this == obj) { 075 return true; 076 } else if (null == obj || !getClass().equals(obj.getClass())) { 077 return false; 078 } 079 return true; 080 } 081 082 @Override 083 public int hashCode() { 084 return getClass().hashCode(); 085 } 086}