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* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.avalon.framework.component;
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.
Author: Avalon Development Team See Also: Version: $Id: ComponentManager.java 506231 2007-02-12 02:36:54Z crossley $
/**
* A <code>ComponentManager</code> selects <code>Component</code>s based on a
* role. The contract is that all the <code>Component</code>s implement the
* differing roles and there is one <code>Component</code> per role. If you
* need to select on of many <code>Component</code>s that implement the same
* role, then you need to use a <code>ComponentSelector</code>. Roles are
* usually the full interface name.
*
* <p>
* 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.
* </p>
*
* <p>
* Below is a list of things that might be considered the different roles:
* </p>
*
* <ul>
* <li> InputAdapter and OutputAdapter</li>
* <li> Store and Spool</li>
* </ul>
*
* <p>
* The <code>ComponentManager</code> does not specify the methodology of
* getting the <code>Component</code>, merely the interface used to get it.
* Therefore the <code>ComponentManager</code> can be implemented with a
* factory pattern, an object pool, or a simple Hashtable.
* </p>
*
* <p>
* <span style="color: red">Deprecated: </span><i>
* Use {@link org.apache.avalon.framework.service.ServiceManager} instead.
* </i>
* </p>
*
* @see org.apache.avalon.framework.component.Component
* @see org.apache.avalon.framework.component.Composable
* @see org.apache.avalon.framework.component.ComponentSelector
*
* @author <a href="mailto:dev@avalon.apache.org">Avalon Development Team</a>
* @version $Id: ComponentManager.java 506231 2007-02-12 02:36:54Z crossley $
*/
public interface ComponentManager
{
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 (...)
{
...
}
Params: - key – The key name of the
Component to retrieve.
Throws: - ComponentException – if an error occurs
Returns: the desired component
/**
* Get the <code>Component</code> associated with the given key. For
* instance, If the <code>ComponentManager</code> had a
* <code>LoggerComponent</code> stored and referenced by key, I would use
* the following call:
* <pre>
* try
* {
* LoggerComponent log;
* myComponent = (LoggerComponent) m_manager.lookup(LoggerComponent.ROLE);
* }
* catch (...)
* {
* ...
* }
* </pre>
*
* @param key The key name of the <code>Component</code> to retrieve.
* @return the desired component
* @throws ComponentException if an error occurs
*/
Component lookup( String key )
throws ComponentException;
Check to see if a Component exists for a key.
Params: - key – a string identifying the key to check.
Returns: True if the component exists, False if it does not.
/**
* Check to see if a <code>Component</code> exists for a key.
*
* @param key a string identifying the key to check.
* @return True if the component exists, False if it does not.
*/
boolean hasComponent( String key );
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.
Params: - component – The Component we are releasing.
/**
* Return the <code>Component</code> when you are finished with it. This
* allows the <code>ComponentManager</code> 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.
*
* @param component The Component we are releasing.
*/
void release( Component component );
}