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
032    /**
033     * Creates a new instance of this version filter.
034     */
035    public HighestVersionFilter() {}
036
037    public void filterVersions(VersionFilterContext context) {
038        Iterator<Version> it = context.iterator();
039        for (boolean hasNext = it.hasNext(); hasNext; ) {
040            it.next();
041            hasNext = it.hasNext();
042            if (hasNext) {
043                it.remove();
044            }
045        }
046    }
047
048    public VersionFilter deriveChildFilter(DependencyCollectionContext context) {
049        return this;
050    }
051
052    @Override
053    public boolean equals(Object obj) {
054        if (this == obj) {
055            return true;
056        } else if (null == obj || !getClass().equals(obj.getClass())) {
057            return false;
058        }
059        return true;
060    }
061
062    @Override
063    public int hashCode() {
064        return getClass().hashCode();
065    }
066}