Hi,
I want to use pooled PreparedStatement feature of PoolingConnection,
I try to write the following code:
-----------------------------------------------------
try
{
con = DriverManager.getConnection(url);
}
catch (Exception e)
{
throw new RuntimeException(e);
}
con = new PoolingConnection(con);
--------------------------------------------------------
Later I am trying to get a PreparedStatement from this connection,
however there is an error occurred.
After I change the above code to:
---------------------------------------------------------
try
{
con = DriverManager.getConnection(url);
}
catch (Exception e)
{
throw new RuntimeException(e);
}
con = new PoolingConnection(con);
KeyedObjectPool stmtPool =
new GenericKeyedObjectPool(
(PoolingConnection) con,
8, //max active
GenericKeyedObjectPool.WHEN_EXHAUSTED_GROW,
1 * 1000, //max wait
1 //max idle
);
con = new PoolingConnection(con, stmtPool);
-----------------------------------------------------------------
Everything is ok, however, it is ugly that a PoolingConnection
is created twice in order to make it work!
Take a look at the source code of PoolingConnection:
-----------------------------------------------------------------
/**
* Constructor.
* @param c the underlying {@link Connection}.
*/
public PoolingConnection(Connection c) {
super(c);
}
/**
* Constructor.
* @param c the underlying {@link Connection}.
* @param maxSleepingPerKey the maximum number of {@link PreparedStatement}s that
may sit idle in my pool (per type)
*/
public PoolingConnection(Connection c, KeyedObjectPool pool) {
super(c);
_pstmtPool = pool;
}
-----------------------------------------------------------------
I wonder why the first constructor do not create a default stmtPool instead of
leave it null, isn't it better to write first constructor like this:
/**
* Constructor.
* @param c the underlying {@link Connection}.
*/
public PoolingConnection(Connection c) {
super(c);
_pstmtPool = new GenericKeyedObjectPool(
this,
DEF_MAX_ACTIVE, //max active
GenericKeyedObjectPool.WHEN_EXHAUSTED_GROW,
DEF_MAX_WAITE, //max wait
DEF_MAX_IDLE //max idle
);
}
Best Regards,
Green
