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.activemq.jndi;
018    
019    import javax.naming.NameNotFoundException;
020    import javax.naming.NamingException;
021    
022    /**
023     * Allows users to dynamically create items
024     * 
025     * 
026     */
027    public abstract class LazyCreateContext extends ReadOnlyContext {
028        public Object lookup(String name) throws NamingException {
029            try {
030                return super.lookup(name);
031            } catch (NameNotFoundException e) {
032                Object answer = createEntry(name);
033                if (answer == null) {
034                    throw e;
035                }
036                internalBind(name, answer);
037                return answer;
038            }
039        }
040    
041        protected abstract Object createEntry(String name);
042    }