org.apache.tapestry.internal.services
Interface ComponentInstantiatorSource

All Superinterfaces:

InvalidationEventHub

All Known Implementing Classes:

ComponentInstantiatorSourceImpl

public interface ComponentInstantiatorSource
extends InvalidationEventHub

Creates Instantiators for components, based on component class name. This will involve transforming the component's class before it is loaded.

In addition, a source acts as an event hub for InvalidationListeners, so that any information derived from loaded classes can be discarded and rebuilt when classes change.

The strategy used is that when any class (in a controlled package) changes, the entire class loader is discarded, along with any instances derived from those classes. A new class loader is created, and then invalidation events are fired to listeners.

Method Summary

void	addPackage(String packageName) Adds a controlled package.
boolean	exists(String className) Checks to see if a fully qualfied class name exists.
Instantiator	findInstantiator(String classname) Given the name of a component class, provides an instantiator for that component.
ClassFactory	getClassFactory() Returns a class factory that can be used to generate additional classes around enhanced classes, or create subclasses of enhanced classes.

Methods inherited from interface org.apache.tapestry.internal.event.InvalidationEventHub

addInvalidationListener

Method Detail

findInstantiator

Instantiator findInstantiator(String classname)

Given the name of a component class, provides an instantiator for that component. Instantiators are cached, so repeated calls to this method with the same class name will return the same instance; however, callers should also be aware that the instantiators may lose validity after an invalidation (caused by changes to external Java class files).

Parameters:

classname - FQCN to find (and perhaps transform and load)

Returns:

an object which can instantiate an instance of the component

addPackage

void addPackage(String packageName)

Adds a controlled package. Only classes within controlled packages are subject to transformation.

Parameters:

packageName - the package name to add (must not be blank)

exists

boolean exists(String className)

Checks to see if a fully qualfied class name exists.

Parameters:

className - name of class to check

Returns:

true if the class exists (there's a ".class" file), false otherwise

getClassFactory

ClassFactory getClassFactory()

Returns a class factory that can be used to generate additional classes around enhanced classes, or create subclasses of enhanced classes.