bundles/org.eclipse.ui.workbench/Eclipse UI/org/eclipse/ui/internal/CycleBaseHandler.java - platform/eclipse.platform.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2007, 2009 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:
  *     IBM Corporation - initial API and implementation
  *     Dina Sayed, dsayed@eg.ibm.com, IBM -  bug 276324
  ******************************************************************************/

 package org.eclipse.ui.internal;

 import org.eclipse.core.commands.AbstractHandler;
 import org.eclipse.core.commands.ExecutionEvent;
 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.core.commands.ParameterizedCommand;
 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IConfigurationElement;
 import org.eclipse.core.runtime.IExecutableExtension;
 import org.eclipse.jface.bindings.Trigger;
 import org.eclipse.jface.bindings.TriggerSequence;
 import org.eclipse.jface.bindings.keys.KeyStroke;
 import org.eclipse.jface.bindings.keys.SWTKeySupport;
 import org.eclipse.jface.preference.IPreferenceStore;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.FocusEvent;
 import org.eclipse.swt.events.FocusListener;
 import org.eclipse.swt.events.KeyEvent;
 import org.eclipse.swt.events.KeyListener;
 import org.eclipse.swt.events.MouseEvent;
 import org.eclipse.swt.events.MouseListener;
 import org.eclipse.swt.events.TraverseEvent;
 import org.eclipse.swt.events.TraverseListener;
 import org.eclipse.swt.graphics.Rectangle;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Table;
 import org.eclipse.swt.widgets.TableColumn;
 import org.eclipse.swt.widgets.TableItem;
 import org.eclipse.ui.IEditorReference;
 import org.eclipse.ui.IPerspectiveDescriptor;
 import org.eclipse.ui.IWorkbenchPage;
 import org.eclipse.ui.IWorkbenchPart;
 import org.eclipse.ui.IWorkbenchPartReference;
 import org.eclipse.ui.IWorkbenchWindow;
 import org.eclipse.ui.contexts.IContextService;
 import org.eclipse.ui.handlers.HandlerUtil;
 import org.eclipse.ui.keys.IBindingService;

 /**
  * Its a base class for switching between views/editors/perspectives.
  *
  * @since 3.3
  *
  */

 public abstract class CycleBaseHandler extends AbstractHandler implements
 		IExecutableExtension {
 	private Object selection;
 	protected IWorkbenchWindow window;
 	// true to go to next and false to go to previous part
 	protected boolean gotoDirection;
 	/**
 	 * The list of key bindings for the backward command when it is open. This
 	 * value is <code>null</code> if the dialog is not open.
 	 */
 	private TriggerSequence[] backwardTriggerSequences = null;

 	protected ParameterizedCommand commandBackward = null;

 	protected ParameterizedCommand commandForward = null;
 	/**
 	 * The list of key bindings for the forward command when it is open. This
 	 * value is <code>null</code> if the dialog is not open.
 	 */
 	private TriggerSequence[] forwardTriggerSequences = null;

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.core.commands.IHandler#execute(org.eclipse.core.commands.ExecutionEvent)
 	 */

 	/**
 	 * Add all items to the dialog in the activation order
 	 */
 	protected abstract void addItems(Table table, WorkbenchPage page);

 	/**
 	 * Get the index of the current item (not valid if there are no items).
 	 */
 	protected int getCurrentItemIndex() {
 		return 0;
 	}

 	/**
 	 * Get the backward command.
 	 */
 	protected abstract ParameterizedCommand getBackwardCommand();

 	/**
 	 * Get the forward command.
 	 */
 	protected abstract ParameterizedCommand getForwardCommand();

 	public Object execute(ExecutionEvent event) throws ExecutionException {
 		window = HandlerUtil.getActiveWorkbenchWindowChecked(event);

 		IWorkbenchPage page = window.getActivePage();
 		IWorkbenchPart activePart= page.getActivePart();
 		getTriggers();
 		openDialog((WorkbenchPage) page, activePart);
 		clearTriggers();
 		activate(page, selection);

 		return null;
 	}

 	/*
 	 * Open a dialog showing all views in the activation order
 	 */
 	protected void openDialog(WorkbenchPage page, IWorkbenchPart activePart) {
 		final int MAX_ITEMS = 22;
 		Shell shell = null;
 		selection = null;

 		if (activePart != null)
 			shell = activePart.getSite().getShell();
 		if (shell == null)
 			shell = window.getShell();
 		final Shell dialog = new Shell(shell, SWT.MODELESS);
 		Display display = dialog.getDisplay();
 		dialog.setLayout(new FillLayout());

 		final Table table = new Table(dialog, SWT.SINGLE | SWT.FULL_SELECTION);
 		table.setHeaderVisible(true);
 		table.setLinesVisible(true);
 		TableColumn tc = new TableColumn(table, SWT.NONE);
 		tc.setResizable(false);
 		tc.setText(getTableHeader(activePart));
 		addItems(table, page);
 		int tableItemCount = table.getItemCount();

 		switch (tableItemCount) {
 		case 0:
 			cancel(dialog);
 			return;
 		case 1:
 			table.setSelection(0);
 			break;
 		default:
 			int i;
 			if (gotoDirection) {
 				i= getCurrentItemIndex() + 1;
 				if (i >= tableItemCount)
 					i= 0;
 			} else {
 				i= getCurrentItemIndex() - 1;
 				if (i < 0)
 					i= tableItemCount - 1;
 			}
 			table.setSelection(i);
 		}

 		tc.pack();
 		table.pack();
 		dialog.pack();

 		Rectangle tableBounds = table.getBounds();
 		tableBounds.height = Math.min(tableBounds.height, table.getItemHeight()
 				* MAX_ITEMS);
 		table.setBounds(tableBounds);

 		dialog.setBounds(dialog.computeTrim(tableBounds.x, tableBounds.y,
 				tableBounds.width, tableBounds.height));

 		tc.setWidth(table.getClientArea().width);
 		table.setFocus();
 		table.addFocusListener(new FocusListener() {
 			public void focusGained(FocusEvent e) {
 				// Do nothing
 			}

 			public void focusLost(FocusEvent e) {
 				cancel(dialog);
 			}
 		});

 		setDialogLocation(dialog, activePart);

 		final IContextService contextService = (IContextService) window
 				.getWorkbench().getService(IContextService.class);
 		try {
 			dialog.open();
 			addMouseListener(table, dialog);
 			contextService.registerShell(dialog, IContextService.TYPE_NONE);
 			addKeyListener(table, dialog);
 			addTraverseListener(table);

 			while (!dialog.isDisposed()) {
 				if (!display.readAndDispatch()) {
 					display.sleep();
 				}
 			}
 		} finally {
 			if (!dialog.isDisposed()) {
 				cancel(dialog);
 			}
 			contextService.unregisterShell(dialog);
 		}
 	}

 	/**
 	 * Sets the dialog's location on the screen.
 	 *
 	 * @param dialog
 	 */
 	protected void setDialogLocation(final Shell dialog, IWorkbenchPart activePart) {
 		Display display = dialog.getDisplay();
 		Rectangle dialogBounds = dialog.getBounds();
 		Rectangle parentBounds = dialog.getParent().getBounds();

 		// the bounds of the monitor that contains the currently active part.
 		Rectangle monitorBounds = activePart == null ? display
 .getPrimaryMonitor().getBounds()
 				: ((Control) ((PartSite) activePart.getSite()).getModel().getWidget()).getMonitor()
 						.getBounds();

 		// Place it in the center of its parent;
 		dialogBounds.x = parentBounds.x
 				+ ((parentBounds.width - dialogBounds.width) / 2);
 		dialogBounds.y = parentBounds.y
 				+ ((parentBounds.height - dialogBounds.height) / 2);
 		if (!monitorBounds.contains(dialogBounds.x, dialogBounds.y)
 				|| !monitorBounds.contains(dialogBounds.x + dialogBounds.width,
 						dialogBounds.y + dialogBounds.height)) {
 			// Place it in the center of the monitor if it is not visible
 			// when placed in the center of its parent.
 			// Ensure the origin is visible on the screen.
 			dialogBounds.x = Math.max(0,
 					monitorBounds.x + (monitorBounds.width - dialogBounds.width) / 2);
 			dialogBounds.y =  Math.max(0,
 					monitorBounds.y + (monitorBounds.height - dialogBounds.height) / 2);
 		}

 		dialog.setLocation(dialogBounds.x, dialogBounds.y);
 	}

 	/**
 	 * Clears the forward and backward trigger sequences.
 	 */
 	protected void clearTriggers() {
 		forwardTriggerSequences = null;
 		backwardTriggerSequences = null;
 	}

 	/**
 	 * Fetch the key bindings for the forward and backward commands. They will
 	 * not change while the dialog is open, but the context will. Bug 55581.
 	 */
 	protected void getTriggers() {
 		commandForward = getForwardCommand();
 		commandBackward = getBackwardCommand();

 		final IBindingService bindingService = (IBindingService) window
 				.getWorkbench().getService(IBindingService.class);
 		forwardTriggerSequences = bindingService
 				.getActiveBindingsFor(commandForward);
 		backwardTriggerSequences = bindingService
 				.getActiveBindingsFor(commandBackward);
 	}

 	protected void addKeyListener(final Table table, final Shell dialog) {
 		table.addKeyListener(new KeyListener() {
 			private boolean firstKey = true;

 			private boolean quickReleaseMode = false;

 			public void keyPressed(KeyEvent e) {
 				int keyCode = e.keyCode;
 				char character = e.character;
 				int accelerator = SWTKeySupport
 						.convertEventToUnmodifiedAccelerator(e);
 				KeyStroke keyStroke = SWTKeySupport
 						.convertAcceleratorToKeyStroke(accelerator);

 				boolean acceleratorForward = false;
 				boolean acceleratorBackward = false;

 				if (commandForward != null) {
 					if (forwardTriggerSequences != null) {
 						final int forwardCount = forwardTriggerSequences.length;
 						for (int i = 0; i < forwardCount; i++) {
 							final TriggerSequence triggerSequence = forwardTriggerSequences[i];

 							// Compare the last key stroke of the binding.
 							final Trigger[] triggers = triggerSequence
 									.getTriggers();
 							final int triggersLength = triggers.length;
 							if ((triggersLength > 0)
 									&& (triggers[triggersLength - 1]
 											.equals(keyStroke))) {
 								acceleratorForward = true;
 								break;
 							}
 						}
 					}
 				}

 				if (commandBackward != null) {
 					if (backwardTriggerSequences != null) {
 						final int backwardCount = backwardTriggerSequences.length;
 						for (int i = 0; i < backwardCount; i++) {
 							final TriggerSequence triggerSequence = backwardTriggerSequences[i];

 							// Compare the last key stroke of the binding.
 							final Trigger[] triggers = triggerSequence
 									.getTriggers();
 							final int triggersLength = triggers.length;
 							if ((triggersLength > 0)
 									&& (triggers[triggersLength - 1]
 											.equals(keyStroke))) {
 								acceleratorBackward = true;
 								break;
 							}
 						}
 					}
 				}

 				if (character == SWT.CR || character == SWT.LF) {
 					ok(dialog, table);
 				} else if (acceleratorForward) {
 					if (firstKey && e.stateMask != 0) {
 						quickReleaseMode = true;
 					}

 					int index = table.getSelectionIndex();
 					table.setSelection((index + 1) % table.getItemCount());
 				} else if (acceleratorBackward) {
 					if (firstKey && e.stateMask != 0) {
 						quickReleaseMode = true;
 					}

 					int index = table.getSelectionIndex();
 					table.setSelection(index >= 1 ? index - 1 : table
 							.getItemCount() - 1);
 				} else if (keyCode != SWT.ALT && keyCode != SWT.COMMAND
 						&& keyCode != SWT.CTRL && keyCode != SWT.SHIFT
 						&& keyCode != SWT.ARROW_DOWN && keyCode != SWT.ARROW_UP
 						&& keyCode != SWT.ARROW_LEFT
 						&& keyCode != SWT.ARROW_RIGHT) {
 					cancel(dialog);
 				}

 				firstKey = false;
 			}

 			public void keyReleased(KeyEvent e) {
 				int keyCode = e.keyCode;
 				int stateMask = e.stateMask;

 				final IPreferenceStore store = WorkbenchPlugin.getDefault()
 						.getPreferenceStore();
 				final boolean stickyCycle = store
 						.getBoolean(IPreferenceConstants.STICKY_CYCLE);
 				if ((!stickyCycle && (firstKey || quickReleaseMode))
 						&& keyCode == stateMask) {
 					ok(dialog, table);
 				}
 			}
 		});
 	}

 	/**
 	 * Adds a listener to the given table that blocks all traversal operations.
 	 *
 	 * @param table
 	 *            The table to which the traversal suppression should be added;
 	 *            must not be <code>null</code>.
 	 */
 	protected final void addTraverseListener(final Table table) {
 		table.addTraverseListener(new TraverseListener() {
 			/**
 			 * Blocks all key traversal events.
 			 *
 			 * @param event
 			 *            The trigger event; must not be <code>null</code>.
 			 */
 			public final void keyTraversed(final TraverseEvent event) {
 				event.doit = false;
 			}
 		});
 	}

 	/**
 	 * Activate the selected item.
 	 *
 	 * @param page
 	 *            the page
 	 * @param selectedItem
 	 *            the selected item
 	 */
 	protected void activate(IWorkbenchPage page, Object selectedItem) {
 		if (selectedItem != null) {
 			if (selectedItem instanceof IEditorReference) {
 				page.setEditorAreaVisible(true);
 			}
 			if (selectedItem instanceof IWorkbenchPartReference) {
 				IWorkbenchPart part = ((IWorkbenchPartReference) selectedItem)
 						.getPart(true);
 				if (part != null) {
 					page.activate(part);
 				}
 			}

 			if (selectedItem instanceof IPerspectiveDescriptor){
 	            IPerspectiveDescriptor persp = (IPerspectiveDescriptor) selectedItem;
 	            page.setPerspective(persp);
 			}
 		}
 	}

 	/*
 	 * Close the dialog and set selection to null.
 	 */
 	protected void cancel(Shell dialog) {
 		selection = null;
 		dialog.close();
 	}

 	/*
 	 * Close the dialog saving the selection
 	 */
 	protected void ok(Shell dialog, final Table table) {
 		TableItem[] items = table.getSelection();

 		if (items != null && items.length == 1) {
 			selection = items[0].getData();
 		}

 		dialog.close();
 	}

 	/*
 	 * Add mouse listener to the table closing it when the mouse is pressed.
 	 */
 	protected void addMouseListener(final Table table, final Shell dialog) {
 		table.addMouseListener(new MouseListener() {
 			public void mouseDoubleClick(MouseEvent e) {
 				ok(dialog, table);
 			}

 			public void mouseDown(MouseEvent e) {
 				ok(dialog, table);
 			}

 			public void mouseUp(MouseEvent e) {
 				ok(dialog, table);
 			}
 		});
 	}

 	protected abstract String getTableHeader(IWorkbenchPart activePart);

 	// return WorkbenchMessages.CyclePartAction_header;

 	public Object getSelection() {
 		return selection;
 	}

 	public IWorkbenchWindow getWindow() {
 		return window;
 	}

 	public TriggerSequence[] getBackwardTriggerSequences() {
 		return backwardTriggerSequences;
 	}

 	public TriggerSequence[] getForwardTriggerSequences() {
 		return forwardTriggerSequences;
 	}

 	/*
 	 * (non-Javadoc)
 	 *
 	 * @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement,
 	 *      java.lang.String, java.lang.Object)
 	 */
 	public void setInitializationData(IConfigurationElement config,
 			String propertyName, Object data) throws CoreException {
 		gotoDirection = "true".equals(data); //$NON-NLS-1$
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2007, 2009 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:
	* IBM Corporation - initial API and implementation
	* Dina Sayed, dsayed@eg.ibm.com, IBM - bug 276324
	******************************************************************************/

	package org.eclipse.ui.internal;

	import org.eclipse.core.commands.AbstractHandler;
	import org.eclipse.core.commands.ExecutionEvent;
	import org.eclipse.core.commands.ExecutionException;
	import org.eclipse.core.commands.ParameterizedCommand;
	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IConfigurationElement;
	import org.eclipse.core.runtime.IExecutableExtension;
	import org.eclipse.jface.bindings.Trigger;
	import org.eclipse.jface.bindings.TriggerSequence;
	import org.eclipse.jface.bindings.keys.KeyStroke;
	import org.eclipse.jface.bindings.keys.SWTKeySupport;
	import org.eclipse.jface.preference.IPreferenceStore;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.FocusEvent;
	import org.eclipse.swt.events.FocusListener;
	import org.eclipse.swt.events.KeyEvent;
	import org.eclipse.swt.events.KeyListener;
	import org.eclipse.swt.events.MouseEvent;
	import org.eclipse.swt.events.MouseListener;
	import org.eclipse.swt.events.TraverseEvent;
	import org.eclipse.swt.events.TraverseListener;
	import org.eclipse.swt.graphics.Rectangle;
	import org.eclipse.swt.layout.FillLayout;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Table;
	import org.eclipse.swt.widgets.TableColumn;
	import org.eclipse.swt.widgets.TableItem;
	import org.eclipse.ui.IEditorReference;
	import org.eclipse.ui.IPerspectiveDescriptor;
	import org.eclipse.ui.IWorkbenchPage;
	import org.eclipse.ui.IWorkbenchPart;
	import org.eclipse.ui.IWorkbenchPartReference;
	import org.eclipse.ui.IWorkbenchWindow;
	import org.eclipse.ui.contexts.IContextService;
	import org.eclipse.ui.handlers.HandlerUtil;
	import org.eclipse.ui.keys.IBindingService;

	/**
	* Its a base class for switching between views/editors/perspectives.
	*
	* @since 3.3
	*
	*/

	public abstract class CycleBaseHandler extends AbstractHandler implements
	IExecutableExtension {
	private Object selection;
	protected IWorkbenchWindow window;
	// true to go to next and false to go to previous part
	protected boolean gotoDirection;
	/**
	* The list of key bindings for the backward command when it is open. This
	* value is <code>null</code> if the dialog is not open.
	*/
	private TriggerSequence[] backwardTriggerSequences = null;

	protected ParameterizedCommand commandBackward = null;

	protected ParameterizedCommand commandForward = null;
	/**
	* The list of key bindings for the forward command when it is open. This
	* value is <code>null</code> if the dialog is not open.
	*/
	private TriggerSequence[] forwardTriggerSequences = null;

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.core.commands.IHandler#execute(org.eclipse.core.commands.ExecutionEvent)
	*/

	/**
	* Add all items to the dialog in the activation order
	*/
	protected abstract void addItems(Table table, WorkbenchPage page);

	/**
	* Get the index of the current item (not valid if there are no items).
	*/
	protected int getCurrentItemIndex() {
	return 0;
	}

	/**
	* Get the backward command.
	*/
	protected abstract ParameterizedCommand getBackwardCommand();

	/**
	* Get the forward command.
	*/
	protected abstract ParameterizedCommand getForwardCommand();

	public Object execute(ExecutionEvent event) throws ExecutionException {
	window = HandlerUtil.getActiveWorkbenchWindowChecked(event);

	IWorkbenchPage page = window.getActivePage();
	IWorkbenchPart activePart= page.getActivePart();
	getTriggers();
	openDialog((WorkbenchPage) page, activePart);
	clearTriggers();
	activate(page, selection);

	return null;
	}

	/*
	* Open a dialog showing all views in the activation order
	*/
	protected void openDialog(WorkbenchPage page, IWorkbenchPart activePart) {
	final int MAX_ITEMS = 22;
	Shell shell = null;
	selection = null;

	if (activePart != null)
	shell = activePart.getSite().getShell();
	if (shell == null)
	shell = window.getShell();
	final Shell dialog = new Shell(shell, SWT.MODELESS);
	Display display = dialog.getDisplay();
	dialog.setLayout(new FillLayout());

	final Table table = new Table(dialog, SWT.SINGLE \| SWT.FULL_SELECTION);
	table.setHeaderVisible(true);
	table.setLinesVisible(true);
	TableColumn tc = new TableColumn(table, SWT.NONE);
	tc.setResizable(false);
	tc.setText(getTableHeader(activePart));
	addItems(table, page);
	int tableItemCount = table.getItemCount();

	switch (tableItemCount) {
	case 0:
	cancel(dialog);
	return;
	case 1:
	table.setSelection(0);
	break;
	default:
	int i;
	if (gotoDirection) {
	i= getCurrentItemIndex() + 1;
	if (i >= tableItemCount)
	i= 0;
	} else {
	i= getCurrentItemIndex() - 1;
	if (i < 0)
	i= tableItemCount - 1;
	}
	table.setSelection(i);
	}

	tc.pack();
	table.pack();
	dialog.pack();

	Rectangle tableBounds = table.getBounds();
	tableBounds.height = Math.min(tableBounds.height, table.getItemHeight()
	* MAX_ITEMS);
	table.setBounds(tableBounds);

	dialog.setBounds(dialog.computeTrim(tableBounds.x, tableBounds.y,
	tableBounds.width, tableBounds.height));

	tc.setWidth(table.getClientArea().width);
	table.setFocus();
	table.addFocusListener(new FocusListener() {
	public void focusGained(FocusEvent e) {
	// Do nothing
	}

	public void focusLost(FocusEvent e) {
	cancel(dialog);
	}
	});

	setDialogLocation(dialog, activePart);

	final IContextService contextService = (IContextService) window
	.getWorkbench().getService(IContextService.class);
	try {
	dialog.open();
	addMouseListener(table, dialog);
	contextService.registerShell(dialog, IContextService.TYPE_NONE);
	addKeyListener(table, dialog);
	addTraverseListener(table);

	while (!dialog.isDisposed()) {
	if (!display.readAndDispatch()) {
	display.sleep();
	}
	}
	} finally {
	if (!dialog.isDisposed()) {
	cancel(dialog);
	}
	contextService.unregisterShell(dialog);
	}
	}

	/**
	* Sets the dialog's location on the screen.
	*
	* @param dialog
	*/
	protected void setDialogLocation(final Shell dialog, IWorkbenchPart activePart) {
	Display display = dialog.getDisplay();
	Rectangle dialogBounds = dialog.getBounds();
	Rectangle parentBounds = dialog.getParent().getBounds();

	// the bounds of the monitor that contains the currently active part.
	Rectangle monitorBounds = activePart == null ? display
	.getPrimaryMonitor().getBounds()
	: ((Control) ((PartSite) activePart.getSite()).getModel().getWidget()).getMonitor()
	.getBounds();

	// Place it in the center of its parent;
	dialogBounds.x = parentBounds.x
	+ ((parentBounds.width - dialogBounds.width) / 2);
	dialogBounds.y = parentBounds.y
	+ ((parentBounds.height - dialogBounds.height) / 2);
	if (!monitorBounds.contains(dialogBounds.x, dialogBounds.y)
	\|\| !monitorBounds.contains(dialogBounds.x + dialogBounds.width,
	dialogBounds.y + dialogBounds.height)) {
	// Place it in the center of the monitor if it is not visible
	// when placed in the center of its parent.
	// Ensure the origin is visible on the screen.
	dialogBounds.x = Math.max(0,
	monitorBounds.x + (monitorBounds.width - dialogBounds.width) / 2);
	dialogBounds.y = Math.max(0,
	monitorBounds.y + (monitorBounds.height - dialogBounds.height) / 2);
	}

	dialog.setLocation(dialogBounds.x, dialogBounds.y);
	}

	/**
	* Clears the forward and backward trigger sequences.
	*/
	protected void clearTriggers() {
	forwardTriggerSequences = null;
	backwardTriggerSequences = null;
	}

	/**
	* Fetch the key bindings for the forward and backward commands. They will
	* not change while the dialog is open, but the context will. Bug 55581.
	*/
	protected void getTriggers() {
	commandForward = getForwardCommand();
	commandBackward = getBackwardCommand();

	final IBindingService bindingService = (IBindingService) window
	.getWorkbench().getService(IBindingService.class);
	forwardTriggerSequences = bindingService
	.getActiveBindingsFor(commandForward);
	backwardTriggerSequences = bindingService
	.getActiveBindingsFor(commandBackward);
	}

	protected void addKeyListener(final Table table, final Shell dialog) {
	table.addKeyListener(new KeyListener() {
	private boolean firstKey = true;

	private boolean quickReleaseMode = false;

	public void keyPressed(KeyEvent e) {
	int keyCode = e.keyCode;
	char character = e.character;
	int accelerator = SWTKeySupport
	.convertEventToUnmodifiedAccelerator(e);
	KeyStroke keyStroke = SWTKeySupport
	.convertAcceleratorToKeyStroke(accelerator);

	boolean acceleratorForward = false;
	boolean acceleratorBackward = false;

	if (commandForward != null) {
	if (forwardTriggerSequences != null) {
	final int forwardCount = forwardTriggerSequences.length;
	for (int i = 0; i < forwardCount; i++) {
	final TriggerSequence triggerSequence = forwardTriggerSequences[i];

	// Compare the last key stroke of the binding.
	final Trigger[] triggers = triggerSequence
	.getTriggers();
	final int triggersLength = triggers.length;
	if ((triggersLength > 0)
	&& (triggers[triggersLength - 1]
	.equals(keyStroke))) {
	acceleratorForward = true;
	break;
	}
	}
	}
	}

	if (commandBackward != null) {
	if (backwardTriggerSequences != null) {
	final int backwardCount = backwardTriggerSequences.length;
	for (int i = 0; i < backwardCount; i++) {
	final TriggerSequence triggerSequence = backwardTriggerSequences[i];

	// Compare the last key stroke of the binding.
	final Trigger[] triggers = triggerSequence
	.getTriggers();
	final int triggersLength = triggers.length;
	if ((triggersLength > 0)
	&& (triggers[triggersLength - 1]
	.equals(keyStroke))) {
	acceleratorBackward = true;
	break;
	}
	}
	}
	}

	if (character == SWT.CR \|\| character == SWT.LF) {
	ok(dialog, table);
	} else if (acceleratorForward) {
	if (firstKey && e.stateMask != 0) {
	quickReleaseMode = true;
	}

	int index = table.getSelectionIndex();
	table.setSelection((index + 1) % table.getItemCount());
	} else if (acceleratorBackward) {
	if (firstKey && e.stateMask != 0) {
	quickReleaseMode = true;
	}

	int index = table.getSelectionIndex();
	table.setSelection(index >= 1 ? index - 1 : table
	.getItemCount() - 1);
	} else if (keyCode != SWT.ALT && keyCode != SWT.COMMAND
	&& keyCode != SWT.CTRL && keyCode != SWT.SHIFT
	&& keyCode != SWT.ARROW_DOWN && keyCode != SWT.ARROW_UP
	&& keyCode != SWT.ARROW_LEFT
	&& keyCode != SWT.ARROW_RIGHT) {
	cancel(dialog);
	}

	firstKey = false;
	}

	public void keyReleased(KeyEvent e) {
	int keyCode = e.keyCode;
	int stateMask = e.stateMask;

	final IPreferenceStore store = WorkbenchPlugin.getDefault()
	.getPreferenceStore();
	final boolean stickyCycle = store
	.getBoolean(IPreferenceConstants.STICKY_CYCLE);
	if ((!stickyCycle && (firstKey \|\| quickReleaseMode))
	&& keyCode == stateMask) {
	ok(dialog, table);
	}
	}
	});
	}

	/**
	* Adds a listener to the given table that blocks all traversal operations.
	*
	* @param table
	* The table to which the traversal suppression should be added;
	* must not be <code>null</code>.
	*/
	protected final void addTraverseListener(final Table table) {
	table.addTraverseListener(new TraverseListener() {
	/**
	* Blocks all key traversal events.
	*
	* @param event
	* The trigger event; must not be <code>null</code>.
	*/
	public final void keyTraversed(final TraverseEvent event) {
	event.doit = false;
	}
	});
	}

	/**
	* Activate the selected item.
	*
	* @param page
	* the page
	* @param selectedItem
	* the selected item
	*/
	protected void activate(IWorkbenchPage page, Object selectedItem) {
	if (selectedItem != null) {
	if (selectedItem instanceof IEditorReference) {
	page.setEditorAreaVisible(true);
	}
	if (selectedItem instanceof IWorkbenchPartReference) {
	IWorkbenchPart part = ((IWorkbenchPartReference) selectedItem)
	.getPart(true);
	if (part != null) {
	page.activate(part);
	}
	}

	if (selectedItem instanceof IPerspectiveDescriptor){
	IPerspectiveDescriptor persp = (IPerspectiveDescriptor) selectedItem;
	page.setPerspective(persp);
	}
	}
	}

	/*
	* Close the dialog and set selection to null.
	*/
	protected void cancel(Shell dialog) {
	selection = null;
	dialog.close();
	}

	/*
	* Close the dialog saving the selection
	*/
	protected void ok(Shell dialog, final Table table) {
	TableItem[] items = table.getSelection();

	if (items != null && items.length == 1) {
	selection = items[0].getData();
	}

	dialog.close();
	}

	/*
	* Add mouse listener to the table closing it when the mouse is pressed.
	*/
	protected void addMouseListener(final Table table, final Shell dialog) {
	table.addMouseListener(new MouseListener() {
	public void mouseDoubleClick(MouseEvent e) {
	ok(dialog, table);
	}

	public void mouseDown(MouseEvent e) {
	ok(dialog, table);
	}

	public void mouseUp(MouseEvent e) {
	ok(dialog, table);
	}
	});
	}

	protected abstract String getTableHeader(IWorkbenchPart activePart);

	// return WorkbenchMessages.CyclePartAction_header;

	public Object getSelection() {
	return selection;
	}

	public IWorkbenchWindow getWindow() {
	return window;
	}

	public TriggerSequence[] getBackwardTriggerSequences() {
	return backwardTriggerSequences;
	}

	public TriggerSequence[] getForwardTriggerSequences() {
	return forwardTriggerSequences;
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.core.runtime.IExecutableExtension#setInitializationData(org.eclipse.core.runtime.IConfigurationElement,
	* java.lang.String, java.lang.Object)
	*/
	public void setInitializationData(IConfigurationElement config,
	String propertyName, Object data) throws CoreException {
	gotoDirection = "true".equals(data); //$NON-NLS-1$
	}
	}