001    /**
002     * 
003     * Copyright 2004 Protique Ltd
004     * 
005     * Licensed under the Apache License, Version 2.0 (the "License"); 
006     * you may not use this file except in compliance with the License. 
007     * 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     **/
018    package org.activemq.jndi;
019    
020    import javax.naming.NameNotFoundException;
021    import javax.naming.NamingException;
022    
023    /**
024     * Allows users to dynamically create items
025     *
026     * @version $Revision: 1.1 $
027     */
028    public abstract class LazyCreateContext extends ReadOnlyContext {
029        public Object lookup(String name) throws NamingException {
030            try {
031                return super.lookup(name);
032            }
033            catch (NameNotFoundException e) {
034                Object answer = createEntry(name);
035                if (answer == null) {
036                    throw e;
037                }
038                internalBind(name, answer);
039                return answer;
040            }
041        }
042    
043        protected abstract Object createEntry(String name);
044    }