DelegatingDataSource.java

package org.theonefx.wcframework.jdbc.datasource;

import java.io.PrintWriter;
import java.sql.Connection;
import java.sql.SQLException;

import javax.sql.DataSource;

import org.theonefx.wcframework.core.InitializableBean;
import org.theonefx.wcframework.utils.Assert;

/**
 * JDBC {@link javax.sql.DataSource} implementation that delegates all calls
 * to a given target {@link javax.sql.DataSource}.
 *
 * <p>This class is meant to be subclassed, with subclasses overriding only
 * those methods (such as {@link #getConnection()}) that should not simply
 * delegate to the target DataSource.
 */
public class DelegatingDataSource implements DataSource, InitializableBean {

	private DataSource targetDataSource;


	/**
	 * Create a new DelegatingDataSource.
	 * @see #setTargetDataSource
	 */
	public DelegatingDataSource() {
	}

	/**
	 * Create a new DelegatingDataSource.
	 * @param targetDataSource the target DataSource
	 */
	public DelegatingDataSource(DataSource targetDataSource) {
		setTargetDataSource(targetDataSource);
	}


	/**
	 * Set the target DataSource that this DataSource should delegate to.
	 */
	public void setTargetDataSource(DataSource targetDataSource) {
		Assert.notNull(targetDataSource, "'targetDataSource' must not be null");
		this.targetDataSource = targetDataSource;
	}

	/**
	 * Return the target DataSource that this DataSource should delegate to.
	 */
	public DataSource getTargetDataSource() {
		return this.targetDataSource;
	}

	public void initialize() {
		if (getTargetDataSource() == null) {
			throw new IllegalArgumentException("Property 'targetDataSource' is required");
		}
	}


	public Connection getConnection() throws SQLException {
		return getTargetDataSource().getConnection();
	}

	public Connection getConnection(String username, String password) throws SQLException {
		return getTargetDataSource().getConnection(username, password);
	}

	public PrintWriter getLogWriter() throws SQLException {
		return getTargetDataSource().getLogWriter();
	}

	public void setLogWriter(PrintWriter out) throws SQLException {
		getTargetDataSource().setLogWriter(out);
	}

	public int getLoginTimeout() throws SQLException {
		return getTargetDataSource().getLoginTimeout();
	}

	public void setLoginTimeout(int seconds) throws SQLException {
		getTargetDataSource().setLoginTimeout(seconds);
	}


	//---------------------------------------------------------------------
	// Implementation of JDBC 4.0's Wrapper interface
	//---------------------------------------------------------------------

	public <T> T  unwrap(Class<T> iface) throws SQLException {
		return getTargetDataSource().unwrap(iface);
	}

	public boolean isWrapperFor(Class<?> iface) throws SQLException {
		return getTargetDataSource().isWrapperFor(iface);
	}

}