nextapp.echo.webcontainer.ServiceRegistry Maven / Gradle / Ivy
/*
* This file is part of the Echo Web Application Framework (hereinafter "Echo").
* Copyright (C) 2002-2009 NextApp, Inc.
*
* Version: MPL 1.1/GPL 2.0/LGPL 2.1
*
* The contents of this file are subject to the Mozilla Public License Version
* 1.1 (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.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS IS" basis,
* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
* for the specific language governing rights and limitations under the
* License.
*
* Alternatively, the contents of this file may be used under the terms of
* either the GNU General Public License Version 2 or later (the "GPL"), or
* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
* in which case the provisions of the GPL or the LGPL are applicable instead
* of those above. If you wish to allow use of your version of this file only
* under the terms of either the GPL or the LGPL, and not to allow others to
* use your version of this file under the terms of the MPL, indicate your
* decision by deleting the provisions above and replace them with the notice
* and other provisions required by the GPL or the LGPL. If you do not delete
* the provisions above, a recipient may use your version of this file under
* the terms of any one of the MPL, the GPL or the LGPL.
*/
package nextapp.echo.webcontainer;
import java.util.HashMap;
import java.util.Map;
/**
* A registry of Service objects that may be recalled based
* on Id values.
*/
public class ServiceRegistry {
/** Maps service Ids to services */
private final Map serviceMap = new HashMap();
/**
* Creates a new ServiceRegistry.
*/
public ServiceRegistry() {
super();
}
/**
* Adds a service to the registry.
*
* By default, this will throw an IllegalArgumentException
* if an attempt to register two different service objects under the same
* service id is made.
*
*
* However, there may be times when it is desirable to simply ignore these
* extra requests and return without throwing an exception, such as when
* a JVM-level shared memory cache is in operation within a cluster. In this
* situation, the service registry may have already been populated by another
* node member, and when the application is first invoked an another node
* member, attempts will be made to populate the registry again. In this
* situation, we just ignore the superfluous requests.
*
*
* In order to turn off the duplicate service id exception for this scenario,
* specify the system property nextapp.echo.webcontainer.ServiceRegistry.disableDuplicateServiceCheck
* with a value of true.
*
* @param service The service to be added.
*/
public synchronized void add(Service service) {
if (serviceMap.containsKey(service.getId())
&& !serviceMap.get(service.getId()).getClass().getName().equals(service.getClass().getName())) {
throw new IllegalArgumentException("Identifier already in use by another service."
+ " id: " + service.getId()
+ " installed service: " + serviceMap.get(service.getId()).getClass().getName()
+ " added service: " + service.getClass().getName());
}
serviceMap.put(service.getId(), service);
}
/**
* Returns the service with the specified Id.
*
* @param id The Id of the service to be retrieved.
* @return The service which is identified by id.
*/
public Service get(String id) {
return (Service) serviceMap.get(id);
}
/**
* Removes a service from the registry.
*
* @param service The service to be removed.
*/
public synchronized void remove(Service service) {
serviceMap.remove(service.getId());
}
}