# DataSourceFinder.java

    /*
     *  Licensed to the Apache Software Foundation (ASF) under one
     *  or more contributor license agreements.  See the NOTICE file
     *  distributed with this work for additional information
     *  regarding copyright ownership.  The ASF licenses this file
     *  to you under the Apache License, Version 2.0 (the
     *  "License"); you may not use this file except in compliance
     *  with the License.  You may obtain a copy of the License at
     *
     *   http://www.apache.org/licenses/LICENSE-2.0
     *
     *  Unless required by applicable law or agreed to in writing,
     *  software distributed under the License is distributed on an
     *   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
     *  KIND, either express or implied.  See the License for the
     *  specific language governing permissions and limitations
     *  under the License.
     */
    package org.apache.synapse.commons.datasource;

    import org.apache.commons.logging.Log;
    import org.apache.commons.logging.LogFactory;
    import org.apache.synapse.commons.SynapseCommonsException;

    import javax.naming.Context;
    import javax.naming.InitialContext;
    import javax.naming.NamingException;
    import javax.sql.DataSource;
    import java.util.Properties;

    /**
     * Utility class to locate DataSources from a JNDI tree
     */
    public class DataSourceFinder {

        private static Log log = LogFactory.getLog(DataSourceFinder.class);

        /**
         * Find a DataSource using the given name and JNDI environment properties
         *
         * @param dsName  Name of the DataSource to be found
         * @param jndiEnv JNDI environment properties
         * @return DataSource if found , otherwise null
         */
        public static DataSource find(String dsName, Properties jndiEnv) {

            try {
                Context context;
                if (jndiEnv == null) {
                    context = new InitialContext();
                } else {
                    context = new InitialContext(jndiEnv);
                }
                return find(dsName, context);

            } catch (NamingException e) {
                throw new SynapseCommonsException("Error looking up DataSource : " + dsName +
                        " using JNDI properties : " + jndiEnv, e, log);
            }
        }

        /**
         * Find a DataSource using the given name and naming context
         *
         * @param dsName  Name of the DataSource to be found
         * @param context Naming Context
         * @return DataSource if found , otherwise null
         */
        public static DataSource find(String dsName, Context context) {

            try {
                Object dataSourceO = context.lookup(dsName);
                if (dataSourceO != null && dataSourceO instanceof DataSource) {
                    return (DataSource) dataSourceO;
                } else {
                    throw new SynapseCommonsException("DataSource : " + dsName + " not found " +
                            "when looking up using JNDI properties : " + context.getEnvironment(), log);
                }

            } catch (NamingException e) {
                throw new SynapseCommonsException("Error looking up DataSource : " + dsName
                        + " using JNDI" + " properties : " + context, e);
            }
        }
    }