*     Renato Silva - out-of-sync extension point (http://bugs.eclipse.org/bugs/show_bug.cgi?id=261716)

 *      

import org.eclipse.jface.viewers.LabelProvider;

import org.eclipse.jface.window.Window;

import org.eclipse.ui.dialogs.ElementListSelectionDialog;

	/**

	 * Represents the out-of-sync handler option together with the associated handler. 

	 */

	private class OutOfSyncHandlerOption {

		private OutOfSyncHandler handler;

		public OutOfSyncHandlerOption(OutOfSyncHandler handler) {

			this.handler = handler;

		}

		public OutOfSyncHandler getHandler() {

			return handler;

		}

		public String toString() {

			return (handler != null)? handler.getAnswer() : null;

		}

	}

	/**

	 * Presents a dialog for asking what to do on out-of-sync saving errors.

	 * @param handlers the available handlers

	 * @return the selected handler 

	 */

	protected OutOfSyncHandler selectOutOfSycHandler(OutOfSyncHandler[] handlers) {

		OutOfSyncHandlerOption[] answers = new OutOfSyncHandlerOption[handlers.length + 1];

		answers[handlers.length] = new OutOfSyncHandlerOption(new OutOfSyncHandler(){			

			public String getAnswer() {

				return EditorMessages.Editor_error_save_outofsync_overwrite;

			}			

			public boolean handle(IProgressMonitor progressMonitor) {

				performSave(true, progressMonitor); 

				return true;

			}			

		});

		for (int i= 0; i < handlers.length; i++) 

			answers[i] = new OutOfSyncHandlerOption(handlers[i]);

		// TODO Option icons and better font size

		// Use another kind of dialog? For example, with radio buttons for each option 

		ElementListSelectionDialog dialog = new ElementListSelectionDialog(getSite().getShell(), new LabelProvider());

		dialog.setElements(answers);

		dialog.setHelpAvailable(false);

		dialog.setAllowDuplicates(true);

		dialog.setMultipleSelection(false);

		dialog.setSize(60, 10);

		dialog.setTitle(EditorMessages.Editor_error_save_outofsync_title);

		dialog.setMessage(NLSUtility.format(EditorMessages.Editor_error_save_outofsync_message, getEditorInput().getToolTipText()));

		dialog.setEmptySelectionMessage(EditorMessages.Editor_error_save_outofsync_no_action_selected);

		if (dialog.open() == Window.OK) {

			Object[] answer = dialog.getResult();

			if (answer != null) 

				return ((OutOfSyncHandlerOption)answer[0]).getHandler();

		}

		return null;

	}

	public static String Editor_error_save_outofsync_no_action_selected;

	public static String Editor_error_save_outofsync_overwrite;

    <extension-point id="outOfSyncHandler" name="Out Of Sync Handler" schema="schema/outOfSyncHandler.exsd"/>

<?xml version='1.0' encoding='UTF-8'?>

<!-- Schema file written by PDE -->

<schema targetNamespace="org.eclipse.ui.workbench.texteditor" xmlns="http://www.w3.org/2001/XMLSchema">

<annotation>

      <appInfo>

         <meta.schema plugin="org.eclipse.ui.workbench.texteditor" id="outOfSyncHandler" name="Out Of Sync Handler"/>

      </appInfo>

      <documentation>

         Allows contributors to handle out-of-sync file savings.

      </documentation>

   </annotation>

   <element name="extension">

      <annotation>

         <appInfo>

            <meta.element />

         </appInfo>

      </annotation>

      <complexType>

         <choice>

            <element ref="handler"/>

         </choice>

         <attribute name="point" type="string" use="required">

            <annotation>

               <documentation>

               </documentation>

            </annotation>

         </attribute>

         <attribute name="id" type="string">

            <annotation>

               <documentation>

               </documentation>

            </annotation>

         </attribute>

         <attribute name="name" type="string">

            <annotation>

               <documentation>

               </documentation>

               <appInfo>

                  <meta.attribute translatable="true"/>

               </appInfo>

            </annotation>

         </attribute>

      </complexType>

   </element>

   <element name="handler">

      <complexType>

         <attribute name="class" type="string" use="required">

            <annotation>

               <documentation>

               </documentation>

               <appInfo>

                  <meta.attribute kind="java" basedOn="org.eclipse.ui.texteditor.OutOfSyncHandler:"/>

               </appInfo>

            </annotation>

         </attribute>

         <attribute name="answer" type="string" use="required">

            <annotation>

               <documentation>

                  Users will be prompted for what to do, and each implementation will be listed as an available action, using this attribute as action description.

For example, the value for a compare and merge handler could be "Compare and merge the versions".

               </documentation>

            </annotation>

         </attribute>

      </complexType>

   </element>

   <annotation>

      <appInfo>

         <meta.section type="since"/>

      </appInfo>

      <documentation>

         3.5

      </documentation>

   </annotation>

   <annotation>

      <appInfo>

         <meta.section type="examples"/>

      </appInfo>

      <documentation>

         [Enter extension point usage example here.]

      </documentation>

   </annotation>

   <annotation>

      <appInfo>

         <meta.section type="apiinfo"/>

      </appInfo>

      <documentation>

         [Enter API information here.]

      </documentation>

   </annotation>

   <annotation>

      <appInfo>

         <meta.section type="implementation"/>

      </appInfo>

      <documentation>

         [Enter information about supplied implementation of this extension point.]

      </documentation>

   </annotation>

</schema>

/*******************************************************************************

 * Copyright (c) 2007, 2008 IBM Corporation and others.

 * 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:

 *     Renato Silva - initial API and implementation 

 *                    (http://bugs.eclipse.org/bugs/show_bug.cgi?id=261716)

 *                    

 *******************************************************************************/

package org.eclipse.ui.texteditor;

import org.eclipse.core.runtime.CoreException;

import org.eclipse.core.runtime.IConfigurationElement;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.core.runtime.Platform;

/**

 * 

 * A handler for file saving when editor content is out-of-sync with the file system.

 */

public abstract class OutOfSyncHandler {

	private static String EXTENSION_POINT_ID = "org.eclipse.ui.workbench.texteditor.outOfSyncHandler"; //$NON-NLS-1$

	private static String ANSWER_ATTRIBUTE = "answer"; //$NON-NLS-1$

	private static String CLASS_ATTRIBUTE = "class"; //$NON-NLS-1$	

	private String answer;

	public static OutOfSyncHandler[] getContributors() {

		OutOfSyncHandler[] result;

		IConfigurationElement[] elements = Platform.getExtensionRegistry().getConfigurationElementsFor(EXTENSION_POINT_ID);

		result = new OutOfSyncHandler[elements.length];

		for (int i= 0; i < elements.length; i++) {

			IConfigurationElement element = elements[i];

			Object executable;

			try {

				executable= elements[i].createExecutableExtension(CLASS_ATTRIBUTE);

				if (executable instanceof OutOfSyncHandler) {

					OutOfSyncHandler handler = ((OutOfSyncHandler) executable);

					handler.answer = element.getAttribute(ANSWER_ATTRIBUTE);

					result[i] = handler;

				}

			} catch (CoreException e) {

				// TODO Log failed contributor instantiation

			}

		}

		return result;

	}

	/** 

	 *  Users will be prompted for what to do on out-of-sync situations.

	 *  This will return the matching answer for the underlying handler.  

	 *  @return the contributed answer

	 */

	public String getAnswer() {

		return answer;

	}

	/**

	 * Handles the file saving when editor content is out-of-sync with the file system. 

	 * Must be implemented appropriately by contributors.

	 * @param monitor the progress monitor

	 * 

	 * @return true for handle success, false for any error

	 */

	//TODO Define parameters (need to include the current text and a 

	//     file system reference to the underlying document

	public abstract boolean handle(IProgressMonitor monitor); 	

}

   <extension

         point="org.eclipse.ui.workbench.texteditor.outOfSyncHandler">

      <handler

            answer="Compare file system and editor versions"

            class="org.eclipse.compare.CompareOutOfSyncHandler">

      </handler>

   </extension>

/*******************************************************************************

 * Copyright (c) 2007, 2008 IBM Corporation and others.

 * 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:

 *     Renato Silva - initial prototype  

 *                    (http://bugs.eclipse.org/bugs/show_bug.cgi?id=261716)

 *******************************************************************************/

package org.eclipse.compare;

import org.eclipse.core.runtime.IProgressMonitor;

import org.eclipse.jface.dialogs.MessageDialog;

import org.eclipse.ui.PlatformUI;

import org.eclipse.ui.texteditor.OutOfSyncHandler;

public class CompareOutOfSyncHandler extends OutOfSyncHandler {

	public boolean handle(IProgressMonitor monitor) {

		//TODO Actual implementation

		MessageDialog.openInformation(

			PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(), 

			"Compare", //$NON-NLS-1$

			"Compare plug-in handled file saving."); //$NON-NLS-1$

		return true;

	}

}