/*
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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
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE
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* or https://OpenDS.dev.java.net/OpenDS.LICENSE.
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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
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* trunk/opends/resource/legal-notices/OpenDS.LICENSE. If applicable,
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* add the following below this CDDL HEADER, with the fields enclosed
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* by brackets "[]" replaced with your own identifying 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 2008-2009 Sun Microsystems, Inc.
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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.admin.std.server.WorkflowElementCfg;
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import org.opends.server.types.Operation;
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import org.opends.server.types.CanceledOperationException;
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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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* @param <T> The type of configuration handled by this workflow element.
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*/
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public abstract class WorkflowElement <T extends WorkflowElementCfg>
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implements Observer
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{
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// Indicates whether the workflow element encapsulates a private local
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// backend.
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private boolean isPrivate = false;
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// An information indicating the type of the current workflow element.
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// This information is for debug and tooling purpose only.
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private String workflowElementTypeInfo = "not defined";
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// The workflow element identifier.
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private String workflowElementID = null;
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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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// 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
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// that identifies the newly created workflow element.
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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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// The observable status of the workflow element.
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// The status contains the health indicator (aka saturation index)
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// of the workflow element.
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private ObservableWorkflowElementStatus observableStatus =
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new ObservableWorkflowElementStatus(this);
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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 ObservableWorkflowElementState getObservableState()
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{
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return observableState;
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}
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/**
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* Provides the observable status of the workflow element.
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*
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* @return the observable status of the workflow element.
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*/
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protected ObservableWorkflowElementStatus getObservableStatus()
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{
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return observableStatus;
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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(
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WorkflowElement<?> we,
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String weid,
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Observer observer
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)
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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 deregistereForStateUpdate(
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WorkflowElement<?> we,
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String weid,
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Observer observer
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)
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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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ObservableWorkflowElementState westate = we.getObservableState();
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westate.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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/**
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* Notifies all the observers who want to be warn when a workflow element
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* is created.
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*
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* @param workflowElement the newly created workflow element
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*/
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public static void notifyStateUpdate(
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WorkflowElement<?> workflowElement)
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{
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// Go through the list of observers and notify them all
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String weID = workflowElement.getWorkflowElementID();
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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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for (Observer observer: observers)
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{
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// The update might fail because an observer could have been
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// terminated. In this case, just ignore the failure and remove
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// the observer from the list of objects to notify.
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try
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{
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observer.update(workflowElement.getObservableState(), null);
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}
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catch(Exception e)
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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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}
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/**
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* Creates a new instance of the workflow element.
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*/
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public WorkflowElement()
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{
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// There is nothing to do in the constructor.
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}
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/**
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* Initializes the instance of the workflow element.
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*
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* @param workflowElementID the workflow element identifier as defined
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* in the configuration.
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* @param workflowElementTypeInfo an information to indicate the type of
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* the current workflow element. For example
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* "Backend" if the current workflow element
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* is a local backend workflow element.
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*/
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public void initialize(
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String workflowElementID,
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String workflowElementTypeInfo)
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{
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this.workflowElementID = workflowElementID;
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this.workflowElementTypeInfo = workflowElementTypeInfo;
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}
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/**
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* {@inheritDoc}
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*/
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public 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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* Get the type of the workflow element. The type is a string information
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* indicating which type is the current workflow element. This information
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* is intended to be used by tools for trace and debug purpose.
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*
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* @return the type of the workflow element.
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*/
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public String getWorkflowElementTypeInfo()
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{
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return this.workflowElementTypeInfo;
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}
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/**
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* Indicates whether the provided configuration is acceptable for
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* this workflow element.
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*
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* @param configuration The workflow element configuration for
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* which to make the determination.
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* @param unacceptableReasons A list that may be used to hold the
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* reasons that the provided
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* configuration is not acceptable.
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*
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* @return {@code true} if the provided configuration is acceptable
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* for this workflow element, or {@code false} if not.
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*/
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public boolean isConfigurationAcceptable(
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T configuration,
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List<String> unacceptableReasons)
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{
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// This default implementation does not perform any special
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// validation. It should be overridden by workflow element
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// implementations that wish to perform more detailed validation.
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return true;
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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 void finalizeWorkflowElement()
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{
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// No action is required by default.
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}
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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 boolean isPrivate()
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{
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return isPrivate;
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}
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/**
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* Specifies whether the workflow element encapsulates a private local
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* backend.
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*
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* @param isPrivate Indicates whether the workflow element encapsulates a
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* private local backend.
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*/
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protected void setPrivate(boolean isPrivate)
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{
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this.isPrivate = isPrivate;
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}
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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 String getWorkflowElementID()
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{
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return workflowElementID;
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}
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/**
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* Modifies the saturation index of the workflow element.
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*
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* @param newValue
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* The new value of the saturation index of the workflow element.
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*/
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public void setSaturationIndex(int newValue)
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{
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observableStatus.setSaturationIndex(newValue);
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}
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/**
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* Gets the saturation index of the workflow element.
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*
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* @return the value of the saturation index of the workflow element.
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*/
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public int getSaturationIndex()
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{
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return observableStatus.getSaturationIndex();
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}
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/**
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* Registers an observer with the saturation index of the workflow
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* element. The observer will be notified when the saturation index
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* is updated.
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*
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* @param observer
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* The observer to notify when the saturation index is modified.
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*/
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public void registerForSaturationIndexUpdate(Observer observer)
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{
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observableStatus.addObserver(observer);
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}
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/**
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* Deregisters an observer with the saturation index of the workflow
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* element.
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*
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* @param observer
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* The observer to deregister.
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*/
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public void deregisterForSaturationIndexUpdate(Observer observer)
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{
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observableStatus.deleteObserver(observer);
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}
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/**
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* Retrieves the list of child workflow elements, ie the
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* WorkflowElements below this one in the topology tree.
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*
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* @return child workflow elements
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*/
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public abstract List<WorkflowElement<?>> getChildWorkflowElements();
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/**
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* Checks whether the tree of workflow elements below this one
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* contains the provided workflow element.
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*
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* @param element The WorkflowElement we are looking for in the topology
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* below this object.
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* @return boolean
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*/
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public boolean hasChildWorkflowElement(WorkflowElement element) {
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if (this.getChildWorkflowElements().size() == 0) {
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return (this.equals(element));
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}
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for (WorkflowElement subElement:this.getChildWorkflowElements()) {
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if (subElement.hasChildWorkflowElement(element)) {
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return true;
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}
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}
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return false;
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}
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}
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