sky.engine.connector.database
Class DBPool

java.lang.Object
  sky.engine.connector.database.DBPool

public class DBPool

extends java.lang.Object

DBPool maintains and recycles open connections to the back-end database. These connections all allocated to forms as needed so that a new connection does not need to be created and destory everytime a form is invoked by the end-user.

$RCSfile: DBPool.java,v $
$Revision: 1.5 $, $Date: 2005/04/24 03:14:04 $

Field Summary

protected DBConnection[]	_cons Open connections in this connection pool.
protected java.lang.String	_jdrv JDBC driver name.
protected java.lang.String	_jurl JDBC URL over which this connection pool works.
protected int	_maxconn Maximum limit on number of connections in this pool.
protected int	_maxstmt Maximum limit on number of statements a connection can have.
protected boolean[]	_used flags to keep track of connections that are being currently used.
static FormattedResourceBundle	STRINGS

Constructor Summary

DBPool(java.lang.String driver, java.lang.String url, int maxconn, int maxstmt)
Constructor.

Method Summary

DBConnection	getConnection() Iterate through all the connections in this connection pool to locate a connection that is not being used.
void	returnConnection(DBConnection conn) Call this function after your done with using a connection.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

_jdrv

protected java.lang.String _jdrv

JDBC driver name.

_jurl

protected java.lang.String _jurl

JDBC URL over which this connection pool works.

_cons

protected DBConnection[] _cons

Open connections in this connection pool.

_used

protected boolean[] _used

flags to keep track of connections that are being currently used.

_maxconn

protected int _maxconn

Maximum limit on number of connections in this pool.

_maxstmt

protected int _maxstmt

Maximum limit on number of statements a connection can have.

STRINGS

public static final FormattedResourceBundle STRINGS

Constructor Detail

DBPool

public DBPool(java.lang.String driver,
              java.lang.String url,
              int maxconn,
              int maxstmt)

Constructor.

Parameters:

driver - JDBC driver name.

url - JDBC URL.

maxconn - Maximum limit on the number of connections in this connection pool.

maxstmt - Maximum limit on the number of statements each connection can have.

Method Detail

getConnection

public DBConnection getConnection()
                           throws ErrorMessage

Iterate through all the connections in this connection pool to locate a connection that is not being used. If all the connections are being used, then create a new connection to return to the caller provided that the maximum limit on number of connections has not been reached.

Returns:

allocated database connection

Throws:

ErrorMessage - in case there are any problems.

returnConnection

public void returnConnection(DBConnection conn)

Call this function after your done with using a connection. This function will mark the connection as unused, clear on state information from the connection, and return it back to the connection pool.

Parameters:

conn - database connection that is currently being used.