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.camel.util.jndi;
018    
019    import java.util.Hashtable;
020    import javax.naming.Context;
021    import javax.naming.NamingException;
022    
023    /**
024     * A factory of the Camel {@link javax.naming.InitialContext} which allows a {@link java.util.Map} to be used to create a
025     * JNDI context.
026     * <p/>
027     * This implementation is singleton based, by creating a <b>new</b> context once, and reusing it on each call to
028     * {@link #getInitialContext(java.util.Hashtable)}.
029     *
030     * @version
031     */
032    public class CamelSingletonInitialContextFactory extends CamelInitialContextFactory {
033    
034        private static volatile Context context;
035    
036        /**
037         * Gets or creates the context with the given environment.
038         * <p/>
039         * This implementation will create the context once, and then return the same instance
040         * on multiple calls.
041         *
042         * @param  environment  the environment, must not be <tt>null</tt>
043         * @return the created context.
044         * @throws javax.naming.NamingException is thrown if creation failed.
045         */
046        public synchronized Context getInitialContext(Hashtable<?, ?> environment) throws NamingException {
047            if (context == null) {
048                context = super.getInitialContext(environment);
049            }
050            return context;
051        }
052    }