Convenient superclass for JNDI-based service locators,
providing configurable lookup of a specific JNDI resource.
Exposes a "jndiName" property. This may or may not
include the "java:comp/env/" prefix expected by Java EE applications when
accessing a locally mapped (Environmental Naming Context) resource. If it
doesn't, the "java:comp/env/" prefix will be prepended if the "resourceRef"
property is true (the default is false) and no other scheme
(e.g. "java:") is given.
Subclasses may invoke the lookup() method whenever it is appropriate.
Some classes might do this on initialization, while others might do it
on demand. The latter strategy is more flexible in that it allows for
initialization of the locator before the JNDI object is available.