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/* |
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* i-scream central monitoring system |
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* http://www.i-scream.org |
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* Copyright (C) 2000-2002 i-scream |
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* |
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* This program is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU General Public License |
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* as published by the Free Software Foundation; either version 2 |
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* of the License, or (at your option) any later version. |
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* |
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* This program is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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* GNU General Public License for more details. |
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* |
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* You should have received a copy of the GNU General Public License |
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* along with this program; if not, write to the Free Software |
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
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*/ |
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|
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//---PACKAGE DECLARATION--- |
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package uk.org.iscream.cms.server.componentmanager; |
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|
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//---IMPORTS--- |
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import org.omg.CORBA.ORB; |
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import org.omg.CosNaming.*; |
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import org.omg.PortableServer.*; |
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import uk.org.iscream.cms.server.core.*; |
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import uk.org.iscream.cms.util.*; |
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|
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/** |
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* This class returns references for global system objects. |
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* This class is used to create and return references to objects |
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* that are required throughout the system. Most of which |
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* are CORBA based. It also manages the ORB for the component. |
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* |
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* It is a singleton object with a static method to obtain a |
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* reference to it. This removes the need for passing |
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* references to all the objects it contains throughout |
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* a component. |
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* |
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* @author $Author: ajm $ |
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* @version $Id: ReferenceManager.java,v 1.20 2003/07/14 16:05:54 ajm Exp $ |
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*/ |
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public class ReferenceManager { |
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|
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//---FINAL ATTRIBUTES--- |
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|
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/** |
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* The current CVS revision of this class |
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*/ |
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public final String REVISION = "$Revision: 1.20 $"; |
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|
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//---STATIC METHODS--- |
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|
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/** |
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* This returns a reference to the single instance of the |
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* ReferenceManager. |
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* |
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* This creates the single instance of the ReferenceManager |
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* if it does not exist by calling the private constructor. |
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* |
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* @return a reference to the ReferenceManager |
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*/ |
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public synchronized static ReferenceManager getInstance() { |
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if (_instance == null) { |
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_instance = new ReferenceManager(); |
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} |
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return _instance; |
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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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* This is a private constructor |
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* This ensures that the system performs according to a Singleton design pattern |
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*/ |
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private ReferenceManager() { |
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_orb = ORB.init(new String[] {}, null); |
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} |
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|
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//---PUBLIC METHODS--- |
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|
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/** |
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* Obtains a CORBA reference through the naming service |
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* for the named object. |
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* Calls the dieWithError() if any exceptions happen! |
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* |
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* @param name the name of the CORBA object to resolve |
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* |
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* @return a reference to the object |
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*/ |
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public org.omg.CORBA.Object getCORBARef(String name) { |
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org.omg.CORBA.Object objRef = null; |
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try { |
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objRef = getNS().resolve(getNS().to_name(name)); |
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} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) { |
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dieWithError("\nCRITICAL:Naming Service Cannot Proceed - when resolving reference to " + name + "!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) { |
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dieWithError("\nCRITICAL:Invalid Name - when resolving reference to " + name + "!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) { |
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recoverWithError("\nCRITICAL:Not Found - when resolving reference to " + name + "!\n" + |
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" Please check that this component is running."); |
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} |
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return objRef; |
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} |
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|
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/** |
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* Binds a given servant with the given name |
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* to the naming service. |
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* Calls the dieWithError() if any exceptions happen! |
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* |
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* @param objRef a reverence to the servant object |
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* @param name the name to bind to the naming service with |
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*/ |
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public void bindToOrb(org.omg.PortableServer.Servant objRef, String name) { |
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try { |
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getNS().bind(getNS().to_name(name), getRootPOA().servant_to_reference(objRef)); |
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} catch (org.omg.PortableServer.POAPackage.WrongPolicy e) { |
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dieWithError("\nCRITICAL:Wrong POA Policy - when binding " + name + "!\n" + |
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" This indicates an error with your ORB."); |
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} catch (org.omg.PortableServer.POAPackage.ServantNotActive e) { |
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dieWithError("\nCRITICAL:ServantNotActive - when binding " + name + "!\n" + |
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" This indicates an error with your ORB."); |
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} catch (org.omg.CosNaming.NamingContextPackage.InvalidName e) { |
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dieWithError("\nCRITICAL:Invalid Name - when binding " + name + "!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (org.omg.CosNaming.NamingContextPackage.CannotProceed e) { |
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dieWithError("\nCRITICAL:Naming Service Cannot Proceed - when binding " + name + "!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (org.omg.CosNaming.NamingContextPackage.NotFound e) { |
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recoverWithError("\nCRITICAL:Naming Service Not Found - when binding " + name + "!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (org.omg.CosNaming.NamingContextPackage.AlreadyBound e) { |
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dieWithError("\nCRITICAL:Already Bound - when binding " + name + "!\n" + |
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" Another component with this name is already running."); |
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} |
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} |
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|
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/** |
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* Activates the POA |
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* Calls the dieWithError() if any exceptions happen! |
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*/ |
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public void activatePOA() { |
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try { |
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getRootPOA().the_POAManager().activate(); |
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} catch (org.omg.PortableServer.POAManagerPackage.AdapterInactive e) { |
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dieWithError("\nCRITICAL:POA Set Inactive - when trying to activate POA!\n" + |
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" This indicates an error with your ORB."); |
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} |
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} |
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|
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/** |
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* Overrides the {@link java.lang.Object#toString() Object.toString()} |
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* method to provide clean logging (every class should have this). |
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* |
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* This uses the uk.org.iscream.cms.util.NameFormat class |
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* to format the toString() |
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* |
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* @return the name of this class and its CVS revision |
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*/ |
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public String toString() { |
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return FormatName.getName( |
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_name, |
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getClass().getName(), |
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REVISION); |
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} |
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|
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//---PRIVATE METHODS--- |
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|
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/** |
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* If there are any CORBA errors this method is called with the |
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* error message. |
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* |
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* The exception this throws is generic to CORBA communication |
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* problems, this is a Runtime exception and is typically only |
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* explicitly caught in the ComponentManager for the current VM |
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* The ComponentManager can then decide what course of action to |
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* take. |
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* |
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* Also, if it can, it will log the message with the logger. |
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* |
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* @param message the error message to die with |
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*/ |
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private void recoverWithError(String message) throws ComponentCORBAException { |
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if (_logger != null) { |
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_logger.write(toString(), Logger.WARNING, "component CORBA error - " + message); |
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} |
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throw new ComponentCORBAException(message); |
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} |
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|
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|
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/** |
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* If there are any CORBA errors this method is called with the |
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* error message. |
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* |
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* Currently this prints the error, on the local err stream. Will |
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* print to the logger if one is available. |
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* |
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* ANY CALLS TO THIS METHOD CAUSE |
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* THE SYSTEM TO EXIT WITH A NON |
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* ZERO CODE! |
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* |
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* @param message the error message to die with |
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*/ |
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private void dieWithError(String message) { |
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System.err.println(message); |
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if (_logger != null) { |
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_logger.write(toString(), Logger.FATAL, message); |
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} |
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System.exit(1); |
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} |
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|
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|
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|
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//---ACCESSOR/MUTATOR METHODS--- |
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|
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/** |
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* Returns a reference to the ORB |
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* |
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* @return the reference this class holds |
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*/ |
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public ORB getORB() { |
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return _orb; |
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} |
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|
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/** |
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* Returns a reference to the Root POA |
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* Calls the dieWithError() if any exceptions happen! |
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* |
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* @return the reference this class holds |
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*/ |
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public POA getRootPOA() { |
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if (_rootPOA == null) { |
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org.omg.CORBA.Object objRef = null; |
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try { |
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objRef = getORB().resolve_initial_references("RootPOA"); |
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} catch (org.omg.CORBA.ORBPackage.InvalidName e) { |
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dieWithError("\nCRITICAL:Unable to resolve reference to the RootPOA!\n" + |
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" This indicates an error with your ORB."); |
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} |
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_rootPOA = POAHelper.narrow(objRef); |
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} |
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return _rootPOA; |
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} |
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|
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/** |
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* Returns a reference to the Naming Service |
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* Calls the dieWithError() if any exceptions happen! |
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* |
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* @return the reference this class holds |
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*/ |
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public NamingContextExt getNS() { |
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if (_ns == null) { |
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org.omg.CORBA.Object objRef = null; |
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try { |
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objRef = getORB().resolve_initial_references("NameService"); |
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} catch (org.omg.CORBA.ORBPackage.InvalidName e) { |
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dieWithError("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" + |
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" Please check with your CORBA naming service provider."); |
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} catch (java.lang.NullPointerException e) { |
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dieWithError("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" + |
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" Please check with your CORBA naming service provider."); |
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} |
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_ns = NamingContextExtHelper.narrow(objRef); |
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} |
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// check we managed to talk to the naming service |
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if (_ns == null) { |
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dieWithError("\nCRITICAL:Unable to resolve reference to the Naming Service!\n" + |
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" Please check with your CORBA naming service provider."); |
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} |
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return _ns; |
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} |
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|
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/** |
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* Returns a reference to the configuration manager |
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* Calls the dieWithError() if any exceptions happen! |
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* |
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* @return the reference this class holds |
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*/ |
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public ConfigurationManager getCM() { |
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if (_cm == null) { |
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_cm = ConfigurationManagerHelper.narrow(getCORBARef("iscream.ConfigurationManager")); |
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} |
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// check we managed to talk to the configuration manager |
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if (_cm == null) { |
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dieWithError("\nCRITICAL:Unable to resolve reference to the Configuration Manager!\n" + |
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" Please check with your CORBA naming service provider."); |
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} |
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return _cm; |
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} |
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|
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/** |
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* Returns a reference to the logger |
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* This will throw a Error if there is an error |
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* |
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* @return the reference this class holds |
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*/ |
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public Logger getLogger() { |
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if (_logger == null) { |
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_logger = LoggerHelper.narrow(getCORBARef("iscream.Logger")); |
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} |
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return _logger; |
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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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* The ORB |
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*/ |
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private ORB _orb; |
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|
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/** |
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* The Naming Service |
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*/ |
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private NamingContextExt _ns; |
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|
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/** |
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* The Root POA |
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*/ |
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private POA _rootPOA; |
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|
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/** |
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* The configuration manager |
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*/ |
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private ConfigurationManager _cm; |
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|
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/** |
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* The logger |
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*/ |
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private Logger _logger; |
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|
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/** |
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* This is the friendly identifier of the |
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* component this class is running in. |
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* eg, a Filter may be called "filter1", |
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* If this class does not have an owning |
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* component, a name from the configuration |
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* can be placed here. This name could also |
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* be changed to null for utility classes. |
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*/ |
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private String _name = null; |
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|
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//---STATIC ATTRIBUTES--- |
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|
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/** |
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* A reference to the single instance of this class |
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*/ |
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private static ReferenceManager _instance = null; |
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} |
