001package org.eclipse.aether.util.graph.version;
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 java.util.Iterator;
023
024import org.eclipse.aether.collection.DependencyCollectionContext;
025import org.eclipse.aether.collection.VersionFilter;
026import org.eclipse.aether.version.Version;
027
028/**
029 * A version filter that excludes any version except the highest one.
030 */
031public final class HighestVersionFilter
032    implements VersionFilter
033{
034
035    /**
036     * Creates a new instance of this version filter.
037     */
038    public HighestVersionFilter()
039    {
040    }
041
042    public void filterVersions( VersionFilterContext context )
043    {
044        Iterator<Version> it = context.iterator();
045        for ( boolean hasNext = it.hasNext(); hasNext; )
046        {
047            it.next();
048            hasNext = it.hasNext();
049            if ( hasNext )
050            {
051                it.remove();
052            }
053        }
054    }
055
056    public VersionFilter deriveChildFilter( DependencyCollectionContext context )
057    {
058        return this;
059    }
060
061    @Override
062    public boolean equals( Object obj )
063    {
064        if ( this == obj )
065        {
066            return true;
067        }
068        else if ( null == obj || !getClass().equals( obj.getClass() ) )
069        {
070            return false;
071        }
072        return true;
073    }
074
075    @Override
076    public int hashCode()
077    {
078        return getClass().hashCode();
079    }
080
081}