/*
 * Copyright 2002-2018 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.jdbc.datasource;

import java.sql.Connection;
import java.sql.Driver;
import java.sql.SQLException;
import java.util.Properties;

import org.springframework.beans.BeanUtils;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

Simple implementation of the standard JDBC DataSource interface, configuring a plain old JDBC Driver via bean properties, and returning a new Connection from every getConnection call. 
NOTE: This class is not an actual connection pool; it does not actually
pool Connections. It just serves as simple replacement for a full-blown
connection pool, implementing the same standard interface, but creating new
Connections on every call.
In a Java EE container, it is recommended to use a JNDI DataSource provided by the container. Such a DataSource can be exposed as a DataSource bean in a Spring ApplicationContext via JndiObjectFactoryBean, for seamless switching to and from a local DataSource bean like this class. 
If you need a "real" connection pool outside of a Java EE container, consider
Apache Commons DBCP
or C3P0.
Commons DBCP's BasicDataSource and C3P0's ComboPooledDataSource are full
connection pool beans, supporting the same basic properties as this class
plus specific settings (such as minimal/maximal pool size etc).
Author:
Juergen Hoeller
See Also:
DriverManagerDataSource
Since:
2.5.5/**
 * Simple implementation of the standard JDBC {@link javax.sql.DataSource} interface,
 * configuring a plain old JDBC {@link java.sql.Driver} via bean properties, and
 * returning a new {@link java.sql.Connection} from every {@code getConnection} call.
 *
 * <p><b>NOTE: This class is not an actual connection pool; it does not actually
 * pool Connections.</b> It just serves as simple replacement for a full-blown
 * connection pool, implementing the same standard interface, but creating new
 * Connections on every call.
 *
 * <p>In a Java EE container, it is recommended to use a JNDI DataSource provided by
 * the container. Such a DataSource can be exposed as a DataSource bean in a Spring
 * ApplicationContext via {@link org.springframework.jndi.JndiObjectFactoryBean},
 * for seamless switching to and from a local DataSource bean like this class.
 *
 * <p>If you need a "real" connection pool outside of a Java EE container, consider
 * <a href="http://commons.apache.org/proper/commons-dbcp">Apache Commons DBCP</a>
 * or <a href="http://sourceforge.net/projects/c3p0">C3P0</a>.
 * Commons DBCP's BasicDataSource and C3P0's ComboPooledDataSource are full
 * connection pool beans, supporting the same basic properties as this class
 * plus specific settings (such as minimal/maximal pool size etc).
 *
 * @author Juergen Hoeller
 * @since 2.5.5
 * @see DriverManagerDataSource
 */
public class SimpleDriverDataSource extends AbstractDriverBasedDataSource {

	@Nullable
	private Driver driver;


	
Constructor for bean-style configuration.
/**
	 * Constructor for bean-style configuration.
	 */
	public SimpleDriverDataSource() {
	}

	
Create a new DriverManagerDataSource with the given standard Driver parameters.
Params:
driver – the JDBC Driver object
url – the JDBC URL to use for accessing the DriverManager
See Also:
Driver.connect(String, Properties)/**
	 * Create a new DriverManagerDataSource with the given standard Driver parameters.
	 * @param driver the JDBC Driver object
	 * @param url the JDBC URL to use for accessing the DriverManager
	 * @see java.sql.Driver#connect(String, java.util.Properties)
	 */
	public SimpleDriverDataSource(Driver driver, String url) {
		setDriver(driver);
		setUrl(url);
	}

	
Create a new DriverManagerDataSource with the given standard Driver parameters.
Params:
driver – the JDBC Driver object
url – the JDBC URL to use for accessing the DriverManager
username – the JDBC username to use for accessing the DriverManager
password – the JDBC password to use for accessing the DriverManager
See Also:
Driver.connect(String, Properties)/**
	 * Create a new DriverManagerDataSource with the given standard Driver parameters.
	 * @param driver the JDBC Driver object
	 * @param url the JDBC URL to use for accessing the DriverManager
	 * @param username the JDBC username to use for accessing the DriverManager
	 * @param password the JDBC password to use for accessing the DriverManager
	 * @see java.sql.Driver#connect(String, java.util.Properties)
	 */
	public SimpleDriverDataSource(Driver driver, String url, String username, String password) {
		setDriver(driver);
		setUrl(url);
		setUsername(username);
		setPassword(password);
	}

	
Create a new DriverManagerDataSource with the given standard Driver parameters.
Params:
driver – the JDBC Driver object
url – the JDBC URL to use for accessing the DriverManager
conProps – the JDBC connection properties
See Also:
Driver.connect(String, Properties)/**
	 * Create a new DriverManagerDataSource with the given standard Driver parameters.
	 * @param driver the JDBC Driver object
	 * @param url the JDBC URL to use for accessing the DriverManager
	 * @param conProps the JDBC connection properties
	 * @see java.sql.Driver#connect(String, java.util.Properties)
	 */
	public SimpleDriverDataSource(Driver driver, String url, Properties conProps) {
		setDriver(driver);
		setUrl(url);
		setConnectionProperties(conProps);
	}


	
Specify the JDBC Driver implementation class to use.
An instance of this Driver class will be created and held
within the SimpleDriverDataSource.
See Also:
setDriver/**
	 * Specify the JDBC Driver implementation class to use.
	 * <p>An instance of this Driver class will be created and held
	 * within the SimpleDriverDataSource.
	 * @see #setDriver
	 */
	public void setDriverClass(Class<? extends Driver> driverClass) {
		this.driver = BeanUtils.instantiateClass(driverClass);
	}

	
Specify the JDBC Driver instance to use.
This allows for passing in a shared, possibly pre-configured
Driver instance.
See Also:
setDriverClass/**
	 * Specify the JDBC Driver instance to use.
	 * <p>This allows for passing in a shared, possibly pre-configured
	 * Driver instance.
	 * @see #setDriverClass
	 */
	public void setDriver(@Nullable Driver driver) {
		this.driver = driver;
	}

	
Return the JDBC Driver instance to use.
/**
	 * Return the JDBC Driver instance to use.
	 */
	@Nullable
	public Driver getDriver() {
		return this.driver;
	}


	@Override
	protected Connection getConnectionFromDriver(Properties props) throws SQLException {
		Driver driver = getDriver();
		String url = getUrl();
		Assert.notNull(driver, "Driver must not be null");
		if (logger.isDebugEnabled()) {
			logger.debug("Creating new JDBC Driver Connection to [" + url + "]");
		}
		return driver.connect(url, props);
	}

}