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.geronimo.kernel.util;
018    
019    import java.util.List;
020    import java.lang.ref.WeakReference;
021    import java.util.ArrayList;
022    
023    
024    public class ClassLoaderRegistry {
025        private final static List<WeakReference> list = new ArrayList<WeakReference>();
026    
027        public synchronized static List getList(){
028            List<ClassLoader> ret = new ArrayList<ClassLoader>();
029            for(int i=0;i<list.size();i++)
030                if(list.get(i) != null) {
031                    ret.add((ClassLoader)list.get(i).get());
032                }
033                else {
034                    list.remove(i);
035                }
036            return ret;
037        }
038        
039        public synchronized static boolean add(ClassLoader cloader){
040            if(contains(cloader)) {
041                return false;
042            }
043            return list.add(new WeakReference<ClassLoader>(cloader));
044        } 
045        
046        public synchronized static boolean contains(ClassLoader cloader){
047            for(int i=0;i<list.size();i++) {
048                WeakReference wk = list.get(i);
049                if(wk.get() == null) {
050                    list.remove(i);
051                }
052                else if(wk.get().equals(cloader))
053                    return true;            
054            }
055            return false;
056        }
057        
058        public synchronized static boolean remove(ClassLoader cloader){
059            boolean result = false;
060            for(int i=0;i<list.size();i++){
061                WeakReference wk = list.get(i);
062                if(wk.get() == null)list.remove(i);
063                else if(wk.get().equals(cloader)){
064                    list.remove(i);
065                    result = true;
066                }
067            }
068            return result;
069        } 
070    }