Package org.apache.avalon.framework.component

Interface ComponentManager

All Known Implementing Classes:
DefaultComponentManager, WrapperComponentManager
public interface ComponentManager
A ComponentManager selects Components based on a role. The contract is that all the Components implement the differing roles and there is one Component per role. If you need to select on of many Components that implement the same role, then you need to use a ComponentSelector. Roles are usually the full interface name.

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 different roles:

  • InputAdapter and OutputAdapter
  • Store and Spool

The ComponentManager does not specify the methodology of getting the Component, merely the interface used to get it. Therefore the ComponentManager can be implemented with a factory pattern, an object pool, or a simple Hashtable.

Deprecated: Use ServiceManager instead.

Version:
CVS $Revision: 1.21 $ $Date: 2004/02/11 14:34:24 $
Author:
Avalon Development Team
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    boolean
    hasComponent(String key)
    Check to see if a Component exists for a key.
    Component
    lookup(String key)
    Get the Component associated with the given key.
    void
    release(Component component)
    Return the Component when you are finished with it.

  • Method Details

    • lookup

      Component lookup(String key) throws ComponentException
      Get the Component associated with the given key. For instance, If the ComponentManager had a LoggerComponent stored and referenced by key, I would use the following call: 
       try
 {
     LoggerComponent log;
     myComponent = (LoggerComponent) m_manager.lookup(LoggerComponent.ROLE);
 }
 catch (...)
 {
     ...
 }
      Parameters:
      key - The key name of the Component to retrieve.
      Returns:
      the desired component
      Throws:
      ComponentException - if an error occurs

    • hasComponent

      boolean hasComponent(String key)
      Check to see if a Component exists for a key.
      Parameters:
      key - a string identifying the key 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 ComponentManager 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 ComponentManager system without having to trap Exceptions on a release.
      Parameters:
      component - The Component we are releasing.