org.apache.avalon.framework.component
public interface ComponentManager
ComponentManager
selects Component
s based on a
role. The contract is that all the Component
s implement the
differing roles and there is one Component
per role. If you
need to select on of many Component
s 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:
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: $Id: ComponentManager.java 30977 2004-07-30 03:57:54 -0500 (Fri, 30 Jul 2004) niclas $
See Also: Component Composable
Method Summary | |
---|---|
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. |
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.
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
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.