257 lines
7.6 KiB
Java
257 lines
7.6 KiB
Java
/*
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* The contents of this file are subject to the Mozilla Public License Version 1.1
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* (the "License"); you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at <http://www.mozilla.org/MPL/>.
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*
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* Software distributed under the License is distributed on an "AS IS" basis, WITHOUT
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* WARRANTY OF ANY KIND, either express or implied. See the License for the specific
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* language governing rights and limitations under the License.
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*
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* The Original Code is the Venice Web Communities System.
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*
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* The Initial Developer of the Original Code is Eric J. Bowersox <erbo@silcom.com>,
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* for Silverwrist Design Studios. Portions created by Eric J. Bowersox are
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* Copyright (C) 2003 Eric J. Bowersox/Silverwrist Design Studios. All Rights Reserved.
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*
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* Contributor(s):
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*/
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package com.silverwrist.dynamo.module;
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import java.util.*;
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import com.silverwrist.dynamo.except.*;
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import com.silverwrist.dynamo.iface.*;
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import com.silverwrist.dynamo.util.*;
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class InstallServiceManager
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{
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/*--------------------------------------------------------------------------------
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* Internal class implementing the install service provider
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*--------------------------------------------------------------------------------
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*/
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private class Services extends BaseDelegatingServiceProvider
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{
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/*====================================================================
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* Constructors
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*====================================================================
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*/
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Services()
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{
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super("Module Initialization Services");
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} // end constructor
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Services(ServiceProvider delegate)
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{
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super("Module Initialization Services",delegate);
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} // end constructor
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/*====================================================================
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* Overrides from class BaseDelegatingServiceProvider
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*====================================================================
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*/
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/**
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* Queries this object for a specified service.
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*
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* @param klass The class of the object that should be returned as a service.
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* @return A service object. The service object is guaranteed to be of the class
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* specified by <CODE>klass</CODE>; that is, if <CODE>queryService(klass)</CODE>
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* yields some object <CODE>x</CODE>, then the expression <CODE>klass.isInstance(x)</CODE>
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* is true.
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* @exception com.silverwrist.dynamo.except.NoSuchServiceException If no service is available in
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* the specified class.
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*/
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public Object queryService(Class klass)
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{
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Object rc = m_service_cache.get(klass);
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if (rc!=null)
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return rc;
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for (int i=(m_service_hooks.size()-1); i>=0; i--)
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{ // call the hooks
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try
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{ // get hooks in reverse order of installation and try them
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ServiceProvider sp = (ServiceProvider)(m_service_hooks.get(i));
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rc = sp.queryService(klass);
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m_service_cache.put(klass,rc);
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return rc;
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} // end try
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catch (NoSuchServiceException e)
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{ // cycle around and keep trying
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} // end catch
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} // end for
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rc = m_services.get(klass);
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if (rc!=null)
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{ // cache the service
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m_service_cache.put(klass,rc);
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return rc;
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} // end if
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return super.queryService(klass);
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} // end queryService
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/**
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* Queries this object for a specified service.
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*
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* @param klass The class of the object that should be returned as a service.
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* @param serviceid ID for the service to be requested, to further discriminate between requests.
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* @return A service object. The service object is guaranteed to be of the class
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* specified by <CODE>klass</CODE>; that is, if <CODE>queryService(klass)</CODE>
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* yields some object <CODE>x</CODE>, then the expression <CODE>klass.isInstance(x)</CODE>
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* is true.
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* @exception com.silverwrist.dynamo.except.NoSuchServiceException If no service is available in
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* the specified class.
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*/
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public Object queryService(Class klass, String serviceid)
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{
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ServiceKey key = new ServiceKey(klass,serviceid);
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Object rc = m_service_cache.get(key);
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if (rc!=null)
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return rc;
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for (int i=(m_service_hooks.size()-1); i>=0; i--)
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{ // call the hooks
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try
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{ // get hooks in reverse order of installation and try them
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ServiceProvider sp = (ServiceProvider)(m_service_hooks.get(i));
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rc = sp.queryService(klass,serviceid);
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m_service_cache.put(key,rc);
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return rc;
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} // end try
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catch (NoSuchServiceException e)
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{ // cycle around and keep trying
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} // end catch
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} // end for
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try
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{ // call through to superclass
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return super.queryService(klass,serviceid);
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} // end try
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catch (NoSuchServiceException e)
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{ // OK, try it without the service ID
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rc = queryService(klass);
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m_service_cache.put(key,rc);
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return rc;
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} // end catch
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} // end queryService
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} // end class Services
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/*--------------------------------------------------------------------------------
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* Internal class for removing hooks
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*--------------------------------------------------------------------------------
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*/
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private class RemoveHook implements ComponentShutdown
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{
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/*====================================================================
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* Attributes
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*====================================================================
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*/
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private ServiceProvider m_sp;
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/*====================================================================
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* Constructor
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*====================================================================
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*/
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RemoveHook(ServiceProvider sp)
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{
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m_sp = sp;
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} // end constructor
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/*====================================================================
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* Implementations from interface ComponentShutdown
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*====================================================================
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*/
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public void shutdown()
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{
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m_service_hooks.remove(m_sp);
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m_service_cache.clear();
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} // end shutdown
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} // end class RemoveHook
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/*--------------------------------------------------------------------------------
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* Attributes
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*--------------------------------------------------------------------------------
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*/
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private Hashtable m_services = new Hashtable();
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private Vector m_service_hooks = new Vector();
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private Hashtable m_service_cache = new Hashtable();
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private ServiceProvider m_base = null;
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/*--------------------------------------------------------------------------------
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* Constructor
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*--------------------------------------------------------------------------------
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*/
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InstallServiceManager()
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{ // do nothing
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} // end constructor
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/*--------------------------------------------------------------------------------
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* External operations
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*--------------------------------------------------------------------------------
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*/
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void addService(Class klass, Object svc)
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{
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m_services.put(klass,svc);
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} // end addService
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synchronized ServiceProvider getServiceProvider()
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{
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if (m_base==null)
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m_base = new Services();
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return m_base;
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} // end getServiceProvider
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ServiceProvider getServiceProvider(ServiceProvider delegate)
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{
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if (delegate==null)
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return this.getServiceProvider();
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else
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return new Services(delegate);
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} // end getServiceProvider
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ComponentShutdown hook(ServiceProvider sp)
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{
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m_service_hooks.add(sp);
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m_service_cache.clear();
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return new RemoveHook(sp);
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} // end hook
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void dispose()
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{
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m_services.clear();
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m_service_hooks.clear();
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m_service_cache.clear();
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m_base = null;
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} // end dispose
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} // end class InstallServiceManager
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