001    /**
002     * Licensed to the Apache Software Foundation (ASF) under one or more
003     * contributor license agreements.  See the NOTICE file distributed with
004     * this work for additional information regarding copyright ownership.
005     * The ASF licenses this file to You under the Apache License, Version 2.0
006     * (the "License"); you may not use this file except in compliance with
007     * the License.  You may obtain a copy of the License at
008     *
009     *     http://www.apache.org/licenses/LICENSE-2.0
010     *
011     *  Unless required by applicable law or agreed to in writing, software
012     *  distributed under the License is distributed on an "AS IS" BASIS,
013     *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
014     *  See the License for the specific language governing permissions and
015     *  limitations under the License.
016     */
017    package org.apache.servicemix.specs.locator;
018    
019    import java.util.concurrent.Callable;
020    import java.util.List;
021    import java.util.Map;
022    import java.util.HashMap;
023    import java.util.ArrayList;
024    import java.util.Set;
025    import java.util.HashSet;
026    
027    public class OsgiLocator {
028    
029        private static Map<String, List<Callable<Class>>> factories;
030    
031        private OsgiLocator() {
032        }
033    
034        public static synchronized void unregister(String id, Callable<Class> factory) {
035            if (factories != null) {
036                List<Callable<Class>> l = factories.get(id);
037                if (l != null) {
038                    l.remove(factory);
039                }
040            }
041        }
042    
043        public static synchronized void register(String id, Callable<Class> factory) {
044            if (factories == null) {
045                factories = new HashMap<String, List<Callable<Class>>>();
046            }
047            List<Callable<Class>> l = factories.get(id);
048            if (l ==  null) {
049                l = new ArrayList<Callable<Class>>();
050                factories.put(id, l);
051            }
052            l.add(factory);
053        }
054    
055        public static synchronized Class locate(String factoryId) {
056            if (factories != null) {
057                List<Callable<Class>> l = factories.get(factoryId);
058                if (l != null && !l.isEmpty()) {
059                    Callable<Class> c = l.get(l.size() - 1);
060                    try {
061                        return c.call();
062                    } catch (Exception e) {
063                    }
064                }
065            }
066            return null;
067        }
068    
069        public static synchronized List<Class> locateAll(String factoryId) {
070            List<Class> classes = new ArrayList<Class>();
071            if (factories != null) {
072                List<Callable<Class>> l = factories.get(factoryId);
073                if (l != null) {
074                    for (Callable<Class> c : l) {
075                            try {
076                            classes.add(c.call());
077                            } catch (Exception e) {
078                            }
079                                    }
080                }
081            }
082            return classes;
083        }
084    
085    }