ComponentInstantiatorSource (Tapestry API - 5.7.0)

All Known Implementing Classes:

ComponentInstantiatorSourceImpl
```
@UsesMappedConfiguration(key=java.lang.String.class,
                         value=ControlledPackageType.class)
public interface ComponentInstantiatorSource
```
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. Starting in Tapestry 5.3, the packages that are loaded are controlled by a configuration that maps package names to ControlledPackageTypes.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`exists(String className)`	Checks to see if a fully qualified class name exists.
`void`	`forceComponentInvalidation()`	Forces invalidation logic, as if a component class on the disk had changed, forcing a reload of all pages and components.
`Instantiator`	`getInstantiator(String classname)`	Given the name of a component class, provides an instantiator for that component.
`PlasticProxyFactory`	`getProxyFactory()`	Returns a proxy factory that can be used to generate additional classes around enhanced classes, or create subclasses of enhanced classes.

- Method Detail
  - getInstantiator
```
Instantiator getInstantiator(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
  - exists
```
boolean exists(String className)
```
    Checks to see if a fully qualified class name exists. This method appears to exist only for testing.
    
    Parameters:
    
    className - name of class to check
    
    Returns:
    
    true if the class exists (there's a ".class" file), false otherwise
  - getProxyFactory
```
PlasticProxyFactory getProxyFactory()
```
    Returns a proxy factory that can be used to generate additional classes around enhanced classes, or create subclasses of enhanced classes.
    
    Since:
    
    5.3
  - forceComponentInvalidation
```
void forceComponentInvalidation()
```
    Forces invalidation logic, as if a component class on the disk had changed, forcing a reload of all pages and components.
    
    Since:
    
    5.3