connectionpool.java

来自「PostgreSQL7.4.6 for Linux」· Java 代码 · 共 97 行

package org.postgresql.jdbc2.optional;

import javax.sql.ConnectionPoolDataSource;
import javax.sql.PooledConnection;
import java.sql.SQLException;
import java.io.Serializable;
import java.io.ObjectOutputStream;
import java.io.ObjectInputStream;
import java.io.IOException;

/**
 * PostgreSQL implementation of ConnectionPoolDataSource.  The app server or
 * middleware vendor should provide a DataSource implementation that takes advantage
 * of this ConnectionPoolDataSource.  If not, you can use the PostgreSQL implementation
 * known as PoolingDataSource, but that should only be used if your server or middleware
 * vendor does not provide their own.  Why? The server may want to reuse the same
 * Connection across all EJBs requesting a Connection within the same Transaction, or
 * provide other similar advanced features.
 *
 * <p>In any case, in order to use this ConnectionPoolDataSource, you must set the property
 * databaseName.  The settings for serverName, portNumber, user, and password are
 * optional.  Note: these properties are declared in the superclass.</p>
 *
 * <p>This implementation supports JDK 1.3 and higher.</p>
 *
 * @author Aaron Mulder ([e-mail])
 * @version $Revision: 1.2.6.1 $
 */
public class ConnectionPool extends BaseDataSource implements Serializable, ConnectionPoolDataSource
{
	private boolean defaultAutoCommit = false;

	/**
	 * Gets a description of this DataSource.
	 */
	public String getDescription()
	{
		return "ConnectionPoolDataSource from " + org.postgresql.Driver.getVersion();
	}

	/**
	 * Gets a connection which may be pooled by the app server or middleware
	 * implementation of DataSource.
	 *
	 * @throws java.sql.SQLException
	 *		   Occurs when the physical database connection cannot be established.
	 */
	public PooledConnection getPooledConnection() throws SQLException
	{
		return new PooledConnectionImpl(getConnection(), defaultAutoCommit);
	}

	/**
	 * Gets a connection which may be pooled by the app server or middleware
	 * implementation of DataSource.
	 *
	 * @throws java.sql.SQLException
	 *		   Occurs when the physical database connection cannot be established.
	 */
	public PooledConnection getPooledConnection(String user, String password) throws SQLException
	{
		return new PooledConnectionImpl(getConnection(user, password), defaultAutoCommit);
	}

	/**
	 * Gets whether connections supplied by this pool will have autoCommit
	 * turned on by default.  The default value is <tt>false</tt>, so that
	 * autoCommit will be turned off by default.
	 */
	public boolean isDefaultAutoCommit()
	{
		return defaultAutoCommit;
	}

	/**
	 * Sets whether connections supplied by this pool will have autoCommit
	 * turned on by default.  The default value is <tt>false</tt>, so that
	 * autoCommit will be turned off by default.
	 */
	public void setDefaultAutoCommit(boolean defaultAutoCommit)
	{
		this.defaultAutoCommit = defaultAutoCommit;
	}

	private void writeObject(ObjectOutputStream out) throws IOException
	{
		writeBaseObject(out);
		out.writeBoolean(defaultAutoCommit);
	}

	private void readObject(ObjectInputStream in) throws IOException, ClassNotFoundException
	{
		readBaseObject(in);
		defaultAutoCommit = in.readBoolean();
	}
}