/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at legal-notices/CDDLv1_0.txt
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* or http://forgerock.org/license/CDDLv1.0.html.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at legal-notices/CDDLv1_0.txt.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information:
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* Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*
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*
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* Copyright 2008-2010 Sun Microsystems, Inc.
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* Portions copyright 2013-2014 ForgeRock AS.
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*/
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package org.opends.server.workflowelement;
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import java.util.List;
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import java.util.Observable;
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import java.util.Observer;
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import java.util.concurrent.ConcurrentHashMap;
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import java.util.concurrent.ConcurrentMap;
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import java.util.concurrent.CopyOnWriteArrayList;
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import org.opends.server.types.CanceledOperationException;
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import org.opends.server.types.Operation;
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/**
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* This class defines the super class for all the workflow elements. A workflow
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* element is a task in a workflow. A workflow element can wrap a physical
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* repository such as a local backend, a remote LDAP server or a local LDIF
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* file. A workflow element can also be used to route operations. This is the
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* case for load balancing and distribution. And workflow element can be used
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* in a virtual environment to transform data (DN and attribute renaming,
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* attribute value renaming...).
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*/
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public abstract class WorkflowElement implements Observer
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{
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/** The observable state of the workflow element. */
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private ObservableWorkflowElementState observableState =
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new ObservableWorkflowElementState(this);
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/**
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* The list of observers who want to be notified when a workflow element
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* required by the observer is created. The key of the map is a string that
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* identifies the newly created workflow element.
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*/
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private static ConcurrentMap<String, List<Observer>>
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newWorkflowElementNotificationList =
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new ConcurrentHashMap<String, List<Observer>>();
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/**
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* Provides the observable state of the workflow element.
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* This method is intended to be called by the WorkflowElementConfigManager
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* that wants to notify observers that the workflow element state has
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* changed (in particular when a workflow element has been disabled).
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*
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* @return the observable state of the workflow element
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*/
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protected final ObservableWorkflowElementState getObservableState()
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{
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return observableState;
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}
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/**
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* Registers with a specific workflow element to be notified when the
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* workflow element state has changed. This notification system is
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* mainly used to be warned when a workflow element is enabled or
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* disabled.
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* <p>
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* If the workflow element <code>we</code> is not <code>null</code>
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* then the <code>observer</code> is registered with the list of objects
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* to notify when <code>we</code> has changed.
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* <p>
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* If the workflow element <code>we</code> is <code>null</code> then
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* the <code>observer</code> is registered with a static list of objects
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* to notify when a workflow element named <code>weid</code> is created.
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*
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* @param we the workflow element. If <code>null</code> then observer
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* is registered with a list of workflow element
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* identifiers.
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* @param weid the identifier of the workflow element. This parameter
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* is useless when <code>we</code> is not <code>null</code>
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* @param observer the observer to notify when the workflow element state
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* has been modified
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*/
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public static void registereForStateUpdate(WorkflowElement we, String weid, Observer observer)
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{
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// If the workflow element "we" exists then register the observer with "we"
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// else register the observer with a static list of workflow element
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// identifiers
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if (we != null)
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{
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ObservableWorkflowElementState westate = we.getObservableState();
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westate.addObserver(observer);
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}
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else
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{
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if (weid == null)
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{
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return;
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}
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List<Observer> observers = newWorkflowElementNotificationList.get(weid);
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if (observers == null)
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{
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// create the list of observers
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observers = new CopyOnWriteArrayList<Observer>();
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observers.add(observer);
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newWorkflowElementNotificationList.put(weid, observers);
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}
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else
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{
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// update the observer list
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observers.add(observer);
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}
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}
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}
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/**
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* Deregisters an observer that was registered with a specific workflow
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* element.
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* <p>
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* If the workflow element <code>we</code> is not <code>null</code>
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* then the <code>observer</code> is deregistered with the list of objects
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* to notify when <code>we</code> has changed.
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* <p>
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* If the workflow element <code>we</code> is <code>null</code> then
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* the <code>observer</code> is deregistered with a static list of objects
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* to notify when a workflow element named <code>weid</code> is created.
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*
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* @param we the workflow element. If <code>null</code> then observer
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* is deregistered with a list of workflow element
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* identifiers.
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* @param weid the identifier of the workflow element. This parameter
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* is useless when <code>we</code> is not <code>null</code>
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* @param observer the observer to deregister
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*/
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public static void deregisterForStateUpdate(WorkflowElement we, String weid, Observer observer)
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{
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// If the workflow element "we" exists then deregister the observer
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// with "we" else deregister the observer with a static list of
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// workflow element identifiers
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if (we != null)
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{
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we.getObservableState().deleteObserver(observer);
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}
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if (weid != null)
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{
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List<Observer> observers = newWorkflowElementNotificationList.get(weid);
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if (observers != null)
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{
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observers.remove(observer);
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}
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}
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}
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/** {@inheritDoc} */
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@Override
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public final void update(Observable o, Object arg)
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{
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// By default, do nothing when notification hits the workflow element.
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}
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/**
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* Performs any finalization that might be required when this
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* workflow element is unloaded. No action is taken in the default
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* implementation.
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*/
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public abstract void finalizeWorkflowElement();
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/**
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* Executes the workflow element for an operation.
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*
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* @param operation the operation to execute
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*
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* @throws CanceledOperationException if this operation should be
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* canceled
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*/
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public abstract void execute(Operation operation)
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throws CanceledOperationException;
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/**
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* Indicates whether the workflow element encapsulates a private
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* local backend.
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*
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* @return <code>true</code> if the workflow element encapsulates a private
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* local backend, <code>false</code> otherwise
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*/
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public abstract boolean isPrivate();
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/**
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* Provides the workflow element identifier.
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*
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* @return the workflow element identifier
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*/
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public abstract String getWorkflowElementID();
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}
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