org.apache.avalon.framework.service
Interface ServiceSelector
- DefaultServiceSelector, WrapperServiceSelector
public interface ServiceSelector
A ServiceSelector
selects Object
s based on a
supplied policy. The contract is that all the Object
s implement the
same role.
Version:
- Avalon Development Team
Serviceable
, ServiceSelector
boolean | isSelectable(Object policy) - Check to see if a
Object exists relative to the supplied policy.
|
void | release(Object object) - Return the
Object when you are finished with it.
|
Object | select(Object policy) - Select the
Object associated with the given policy.
|
isSelectable
public boolean isSelectable(Object policy)
Check to see if a Object
exists relative to the supplied policy.
policy
- a Object
containing the selection criteria
- True if the component is available, False if it not.
release
public void release(Object object)
Return the
Object
when you are finished with it. This
allows the
ServiceSelector
to handle the End-Of-Life Lifecycle
events associated with the
Object
. Please note, that no
Exception should be thrown at this point. This is to allow easy use of the
ServiceSelector system without having to trap Exceptions on a release.
object
- The Object
we are releasing.
select
public Object select(Object policy)
throws ServiceException
Select the
Object
associated with the given policy.
For instance, If the
ServiceSelector
has a
Generator
stored and referenced by a URL, the
following call could be used:
try
{
Generator input;
input = (Generator)selector.select( new URL("foo://demo/url") );
}
catch (...)
{
...
}
policy
- A criteria against which a Object
is selected.
- an
Object
value
ServiceException
- If the requested Object
cannot be supplied
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