001    package org.apache.archiva.proxy;
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    
022    import org.apache.archiva.proxy.model.ProxyConnector;
023    
024    import java.util.Comparator;
025    
026    /**
027     * ProxyConnectorOrderComparator 
028     *
029     *
030     */
031    public class ProxyConnectorOrderComparator
032        implements Comparator<ProxyConnector>
033    {
034        private static ProxyConnectorOrderComparator INSTANCE = new ProxyConnectorOrderComparator();
035    
036        public static ProxyConnectorOrderComparator getInstance()
037        {
038            return INSTANCE;
039        }
040    
041        public int compare( ProxyConnector o1, ProxyConnector o2 )
042        {
043            if ( o1 == null && o2 == null )
044            {
045                return 0;
046            }
047    
048            // Ensure null goes to end of list.
049            if ( o1 == null && o2 != null )
050            {
051                return 1;
052            }
053    
054            if ( o1 != null && o2 == null )
055            {
056                return -1;
057            }
058    
059            // Ensure 0 (unordered) goes to end of list.
060            if ( o1.getOrder() == 0 && o2.getOrder() != 0 )
061            {
062                return 1;
063            }
064    
065            if ( o1.getOrder() != 0 && o2.getOrder() == 0 )
066            {
067                return -1;
068            }
069    
070            return o1.getOrder() - o2.getOrder();
071        }
072    }