ComponentSelector

All Superinterfaces:

Component
```
public interface ComponentSelector
extends Component
```
A ComponentSelector selects Components based on a hint. The contract is that all the Components implement the same role.
A role is better understood by the analogy of a play. There are many different roles in a script. Any actor or actress can play any given part and you get the same results (phrases said, movements made, etc.). The exact nuances of the performance is different.

Below is a list of things that might be considered the same role:
- XMLInputAdapter and PropertyInputAdapter
- FileGenerator and SQLGenerator
The ComponentSelector does not specify the methodology of getting the Component, merely the interface used to get it. Therefore the ComponentSelector can be implemented with a factory pattern, an object pool, or a simple Hashtable.

Deprecated: Use ServiceSelector instead.
Version:

$Id: ComponentSelector.java 30977 2004-07-30 03:57:54 -0500 (Fri, 30 Jul 2004) niclas $

Author:

Avalon Development Team

See Also:

Component, Composable, ComponentManager

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`hasComponent(java.lang.Object hint)`	Check to see if a `Component` exists for a hint.
`void`	`release(Component component)`	Return the `Component` when you are finished with it.
`Component`	`select(java.lang.Object hint)`	Select the `Component` associated with the given hint.

- Method Detail
  - select
```
Component select(java.lang.Object hint)
          throws ComponentException
```
    Select the Component associated with the given hint. For instance, If the ComponentSelector has a Generator stored and referenced by a URL, I would use the following call:
    try { Generator input; input = (Generator)selector.select( new URL("foo://demo/url") ); } catch (...) { ... }
    Parameters:
    
    hint - A hint to retrieve the correct Component.
    
    Returns:
    
    the desired component
    
    Throws:
    
    ComponentException - If the given role is not associated with a Component, or a Component instance cannot be created.
  - hasComponent
```
boolean hasComponent(java.lang.Object hint)
```
    Check to see if a Component exists for a hint.
    
    Parameters:
    
    hint - a string identifying the role to check.
    
    Returns:
    
    True if the component exists, False if it does not.
  - release
```
void release(Component component)
```
    Return the Component when you are finished with it. This allows the ComponentSelector to handle the End-Of-Life Lifecycle events associated with the Component. Please note, that no Exceptions should be thrown at this point. This is to allow easy use of the ComponentSelector system without having to trap Exceptions on a release.
    
    Parameters:
    
    component - The Component we are releasing.