| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you under the Apache License, Version 2.0 (the |
| * "License"); you may not use this file except in compliance |
| * with the License. You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, |
| * software distributed under the License is distributed on an |
| * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY |
| * KIND, either express or implied. See the License for the |
| * specific language governing permissions and limitations |
| * under the License. |
| */ |
| package org.apache.felix.cm.impl; |
| |
| |
| import java.util.Comparator; |
| |
| import org.osgi.framework.Constants; |
| import org.osgi.framework.ServiceReference; |
| import org.osgi.service.cm.ConfigurationPlugin; |
| |
| |
| /** |
| * The <code>RankingComparator</code> may be used to maintain sorted |
| * sets or to sort arrays such that the first element in the set or |
| * array is the one to use first and the last elements the one to |
| * use last. |
| */ |
| public abstract class RankingComparator implements Comparator<ServiceReference<?>> |
| { |
| |
| /** |
| * Implements a comparator to sort arrays and sets according to the |
| * specification of the <code>service.ranking</code> property. This |
| * results in collections whose first element has the highest ranking |
| * and the last element has the lowest ranking. Thus the results of |
| * this comparator are as follows: |
| * <ul> |
| * <li><code>< 0</code> if obj1 has higher ranking than obj2</li> |
| * <li><code>== 0</code> if obj1 and obj2 reference the same service</li> |
| * <li><code>> 0</code> if obj1 has lower ranking than obj2</li> |
| * </ul> |
| */ |
| public static Comparator<ServiceReference<?>> SRV_RANKING = new RankingComparator() |
| { |
| public int compare( ServiceReference<?> obj1, ServiceReference<?> obj2 ) |
| { |
| final long id1 = this.getLong( obj1, Constants.SERVICE_ID ); |
| final long id2 = this.getLong( obj2, Constants.SERVICE_ID ); |
| |
| if ( id1 == id2 ) |
| { |
| return 0; |
| } |
| |
| final int rank1 = this.getInteger( obj1, Constants.SERVICE_RANKING ); |
| final int rank2 = this.getInteger( obj2, Constants.SERVICE_RANKING ); |
| |
| if ( rank1 == rank2 ) |
| { |
| return ( id1 < id2 ) ? -1 : 1; |
| } |
| |
| return ( rank1 > rank2 ) ? -1 : 1; |
| } |
| |
| }; |
| |
| |
| /** |
| * Implements a comparator to sort arrays and sets according to the |
| * specification of the <code>service.cmRanking</code> property in |
| * the Configuration Admin specification. This results in collections |
| * where the first element has the lowest ranking value and the last |
| * element has the highest ranking value. Order amongst elements with |
| * the same ranking value is left undefined, however we order it |
| * by service id, lowest last. Thus the results of this |
| * comparator are as follows: |
| * <ul> |
| * <li><code>< 0</code> if obj1 has lower ranking than obj2</li> |
| * <li><code>== 0</code> if obj1 and obj2 have the same ranking</li> |
| * <li><code>> 0</code> if obj1 has higher ranking than obj2</li> |
| * </ul> |
| */ |
| public static Comparator<ServiceReference<?>> CM_RANKING = new RankingComparator() |
| { |
| public int compare( ServiceReference<?> obj1, ServiceReference<?> obj2 ) |
| { |
| final long id1 = this.getLong( obj1, Constants.SERVICE_ID ); |
| final long id2 = this.getLong( obj2, Constants.SERVICE_ID ); |
| |
| if ( id1 == id2 ) |
| { |
| return 0; |
| } |
| |
| final int rank1 = this.getInteger( obj1, ConfigurationPlugin.CM_RANKING ); |
| final int rank2 = this.getInteger( obj2, ConfigurationPlugin.CM_RANKING ); |
| |
| if ( rank1 == rank2 ) |
| { |
| return ( id1 > id2 ) ? -1 : 1; |
| } |
| |
| return ( rank1 < rank2 ) ? -1 : 1; |
| } |
| |
| }; |
| |
| |
| protected int getInteger( ServiceReference<?> sr, String property ) |
| { |
| Object rankObj = sr.getProperty( property ); |
| if ( rankObj instanceof Integer ) |
| { |
| return ( ( Integer ) rankObj ).intValue(); |
| } |
| |
| // null or not an integer |
| return 0; |
| } |
| |
| protected long getLong( ServiceReference<?> sr, String property ) |
| { |
| Object rankObj = sr.getProperty( property ); |
| if ( rankObj instanceof Long ) |
| { |
| return ( ( Long ) rankObj ).longValue(); |
| } |
| |
| // null or not a long |
| return 0; |
| } |
| } |