org.apache.avalon.framework.component
Interface ComponentManager
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.
CVS $Revision: 1.21 $ $Date: 2004/02/11 14:34:24 $ 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.
|
hasComponent
public boolean hasComponent(String key)
Check to see if a Component exists for a key.
key - a string identifying the key to check.
- True if the component exists, False if it does not.
lookup
public 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 (...)
{
...
}
key - The key name of the Component to retrieve.
release
public 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.
component - The Component we are releasing.