/* $Id: UMLPlainTextDocument.java 17881 2010-01-12 21:09:28Z linus $

  *****************************************************************************

  * Copyright (c) 2009 Contributors - see below

  * All rights reserved. This program and the accompanying materials

  * are made available under the terms of the Eclipse Public License v1.0

  * which accompanies this distribution, and is available at

  * http://www.eclipse.org/legal/epl-v10.html

  *

  * Contributors:

  *    tfmorris

  *****************************************************************************

  *

  * Some portions of this file was previously release using the BSD License:

  */

 // Copyright (c) 1996-2008 The Regents of the University of California. All

 // Rights Reserved. Permission to use, copy, modify, and distribute this

 // software and its documentation without fee, and without a written

 // agreement is hereby granted, provided that the above copyright notice

 // and this paragraph appear in all copies.  This software program and

 // documentation are copyrighted by The Regents of the University of

 // California. The software program and documentation are supplied "AS

 // IS", without any accompanying services from The Regents. The Regents

 // does not warrant that the operation of the program will be

 // uninterrupted or error-free. The end-user understands that the program

 // was developed for research purposes and is advised not to rely

 // exclusively on the program for any reason.  IN NO EVENT SHALL THE

 // UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

 // SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,

 // ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF

 // THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF

 // SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY

 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 // PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF

 // CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,

 // UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 package org.argouml.uml.ui;

 import java.beans.PropertyChangeEvent;

 import javax.swing.text.AttributeSet;

 import javax.swing.text.BadLocationException;

 import javax.swing.text.PlainDocument;

 import org.apache.log4j.Logger;

 import org.argouml.model.AttributeChangeEvent;

 import org.argouml.model.Model;

 import org.argouml.model.ModelEventPump;

 import org.argouml.ui.targetmanager.TargetEvent;

 import org.tigris.gef.presentation.Fig;

 /**

  * Model for a text property on a model element. It listens to

  * property change events for the given property name so that

  * changes made to the underlying UML model are reflected here.

  * <p>

  * NOTE: If you override the insertString() or remove() methods

  * be sure to preserve the flushEvents() calls to keep things

  * synchronized.  Events caused by updates are delivered

  * asynchronously to the actual update calls.

  * <p>

  * @since Oct 6, 2002

  * @author jaap.branderhorst@xs4all.nl

  */

 public abstract class UMLPlainTextDocument

     extends PlainDocument

     implements UMLDocument {

     private static final Logger LOG =

         Logger.getLogger(UMLPlainTextDocument.class);

     /**

      * True if an event should be fired when the text of the document is changed

      */

     private boolean firing = true;

     /**

      * True if an user edits the document directly (by typing in text)

      */

     @Deprecated

     private boolean editing = false;

     /**

      * The target of the propertypanel that's behind this property.

      */

     private Object panelTarget = null;

     /**

      * The name of the property set event that will change the

      * property this document shows.

      */

     private String eventName = null;

     /**

      * Constructor for UMLPlainTextDocument. This takes a panel to set the

      * thirdpartyeventlistener to the given list of events to listen to.

      *

      * @param name the event

      */

     public UMLPlainTextDocument(String name) {

         super();

         setEventName(name);

     }

     /*

      * @see java.beans.PropertyChangeListener#propertyChange(java.beans.PropertyChangeEvent)

      */

     public void propertyChange(PropertyChangeEvent evt) {

         // NOTE: This may be called from a different thread, so we need to be

         // careful of the threading restrictions imposed by AbstractDocument

         // for mutators to be sure we don't deadlock.

         if (evt instanceof AttributeChangeEvent 

                 && eventName.equals(evt.getPropertyName())) {

             updateText((String) evt.getNewValue());

         }

     }

     /**

      * Returns the target.

      * @return Object

      */

     public final Object getTarget() {

         return panelTarget;

     }

     /**

      * Sets the target.

      * @param target The target to set

      */

     public final void setTarget(Object target) {

         target = target instanceof Fig ? ((Fig) target).getOwner() : target;

         if (Model.getFacade().isAUMLElement(target)) {

             if (target != panelTarget) {

                 ModelEventPump eventPump = Model.getPump();

                 if (panelTarget != null) {

                     eventPump.removeModelEventListener(this, panelTarget,

                             getEventName());

                 }

                 panelTarget = target;

                 eventPump.addModelEventListener(this, panelTarget,

                         getEventName());

             }

             updateText(getProperty());

         }

     }

     /*

      * @see javax.swing.text.Document#insertString(

      *         int, java.lang.String, javax.swing.text.AttributeSet)

      */

     public void insertString(int offset, String str, AttributeSet a)

         throws BadLocationException {

         // Mutators hold write lock & will deadlock if use is not thread safe 

         super.insertString(offset, str, a);

         setPropertyInternal(getText(0, getLength()));

     }

     /*

      * @see javax.swing.text.Document#remove(int, int)

      */

     public void remove(int offs, int len) throws BadLocationException {

         // Mutators hold write lock & will deadlock if use is not thread safe 

         super.remove(offs, len);

         setPropertyInternal(getText(0, getLength()));

     }

     /**

      * Wrapped version of setProperty which attempts to keep us from hearing

      * our own echo on the event listener when we change something.  Also

      * skips updates equal the current value. 

      */

     private void setPropertyInternal(String newValue) {

         // TODO: This is updating model on a per character basis as

         // well as unregistering/reregistering event listeners every

         // character - very wasteful - tfm

         if (isFiring() && !newValue.equals(getProperty())) {

             setFiring(false);

             setProperty(newValue);

             Model.getPump().flushModelEvents();

             setFiring(true);

         }

     }

     /**

      * @param text the value of the property

      */

     protected abstract void setProperty(String text);

     /**

      * @return the value of the property

      */

     protected abstract String getProperty();

     /**

      * Enable/disable firing of updates.  As a side effect, it unregisters

      * model event listeners during disable and registers them again during

      * enable.

      * 

      * @param f new firing state.  Pass false to disable updates.

      */

     private final synchronized void setFiring(boolean f) {

         ModelEventPump eventPump = Model.getPump();

         if (f && panelTarget != null) {

             eventPump.addModelEventListener(this, panelTarget, eventName);

         } else {

             eventPump.removeModelEventListener(this, panelTarget, eventName);

         }

         firing = f;

     }

     /**

      * Return the state of the firing flag.  Method is synchronized so it will

      * return the correct value from any thread.

      * 

      * @return true firing of updates is allowed currently. Returns false if we

      *         are in the process of doing an update so that we know to ignore

      *         any resulting events.

      */

     private final synchronized boolean isFiring() {

         return firing;

     }

     private final void updateText(String textValue) {

         try {

             if (textValue == null) {

                 textValue = "";

             }

             String currentValue = getText(0, getLength());

             if (isFiring() && !textValue.equals(currentValue)) {

                 setFiring(false);

                 // Mutators hold write lock & will deadlock 

                 // if use is not thread-safe 

                 super.remove(0, getLength());

                 super.insertString(0, textValue, null);

             }

         } catch (BadLocationException b) {

             LOG.error(

                       "A BadLocationException happened\n"

                       + "The string to set was: "

                       + getProperty(),

                       b);

         } finally {

             setFiring(true);

         }

     }

     /**

      * Returns the eventName.

      * @return String

      */

     public String getEventName() {

         return eventName;

     }

     /**

      * Sets the eventName.

      * @param en The eventName to set

      */

     protected void setEventName(String en) {

         eventName = en;

     }

     /*

      * @see org.argouml.ui.targetmanager.TargetListener#targetAdded(org.argouml.ui.targetmanager.TargetEvent)

      */

     public void targetAdded(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

     /*

      * @see org.argouml.ui.targetmanager.TargetListener#targetRemoved(org.argouml.ui.targetmanager.TargetEvent)

      */

     public void targetRemoved(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

     /*

      * @see org.argouml.ui.targetmanager.TargetListener#targetSet(org.argouml.ui.targetmanager.TargetEvent)

      */

     public void targetSet(TargetEvent e) {

         setTarget(e.getNewTarget());

     }

 }