DataSourceFactory.java

/*
 * Copyright 2013-2014 the original author or authors.
 *
 * Licensed 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.springframework.cloud.aws.jdbc.datasource;

import javax.sql.DataSource;

/**
 * Factory to create {@link DataSource} instances at runtime. In contrast to the regular datasource definitions, this
 * interface allows the dynamic creation of datasource at runtime. This is especially useful and needed if the datasource
 * information like the url, username and password are not available at configuration time. With this factory it
 * is possible to create datasource with configuration information which is fetched while starting the application.
 * Because of the dynamic creation of datasource at runtime, this interface also provides the lifecycle method {@link
 * #closeDataSource(javax.sql.DataSource)} to actually shutdown the created datasource. This method should be called
 * while destroying the application itself.
 * <p>
 * <b>Note:</b> This interface does not assume what kind of datasource is returned. It is strongly recommended to use
 * an already existing and pooled datasource like <a href="http://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html">Tomcat
 * JDBC datasource</a> for real life production applications.
 * </p>
 *
 * @author Agim Emruli
 * @since 1.0
 */
public interface DataSourceFactory {

    /**
     * Creates a datasource with the passed in information. The datasource itself should be fully constructed and
     * initialized to be used in a multi threaded environment.
     *
     * @param dataSourceInformation
     *         - the {@link DataSourceInformation} parameter object which holds all dynamic information for the datasource
     *         creation.
     * @return - a fully initialized datasource instance which can be used by the application to actually interact with a
     * database platform
     */
    DataSource createDataSource(DataSourceInformation dataSourceInformation);

    /**
     * Will be called if the datasource is not used anymore to allow the factory to release any resource that are used by
     * the created object. Implementation should check if the passed in datasource is a "known" datasource and if so
     * interact with the to shutdown the datasource. On well known datasource like Apache Commons DBCP and Apache
     * Tomcat JDBC this method will call the close() method to release any connection which are held in the pool.
     *
     * @param dataSource
     *         - The datasource that is not used anymore and can be destroyed by the factory
     */
    void closeDataSource(DataSource dataSource);

}