web server - Borland Technical Publications

Other Considerations
To illustrate, if the connection factory is com.shme.BadConnectionFactory, extend the
connection factory as com.shme.GoodConnectionFactory, and implement Referenceable as
follows:
package com.shme.shmeAdapter;
public class GoodConnectionFactory
{
private javax.naming.Reference ref;
// ...
public javax.naming.Reference getReference()
{
// implement such that getReference() never returns null
// ...
return ref;
}
public javax.naming.Reference setReference( javax.naming.Reference ref )
// this.ref = ref;
}
//
Also, when dealing with a poorly behaving getReference(), there are various ways to
accomplish this, but principally, the idea is to implement getReference() such that it
never returns null. The best approach is to implement:
■
A fallback mechanism in getReference() which sets the reference to be returned
correctly if the connection factory's reference attribute is null - returning a
registrable javax.naming.Reference object, and
■
A helper class implementing javax.naming.spi.ObjectFactory to provide the fallback
object to create the connection factory object from the valid Reference instance.
To illustrate, if the connection factory is com.shme.BadConnectionFactory, extend the
connection factory as com.shme.GoodConnectionFactory, and override getReference() as
follows:
package com.shme.shmeAdapter;
public class GoodConnectionFactory
{
// ...
public javax.naming.Reference getReference()
{
if ( ref == null )
{
ref = new javax.naming.Reference( this.getClass().getName(),
"com.shme.shmeAdapter.GoodCFObjectFactory"
/* object factory for GoodConnectionFactory references */,
null );
String value;
value = managedCxFactory.getClass().getName();
if ( value != null )
{
ref.add( new javax.naming.StringRefAddr(
"managedconnectionfactory-class", value ) );
}
value = cxManager.getClass().getName();
if ( value != null )
{
280 BES Developer’s Guide