org.eclipse.ltk.ui.refactoring/src/org/eclipse/ltk/internal/ui/refactoring/PreviewWizardPage.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2004 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Common Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/cpl-v10.html
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ltk.internal.ui.refactoring;

 import org.eclipse.compare.CompareUI;

 import org.eclipse.core.runtime.CoreException;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.SashForm;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;

 import org.eclipse.jface.action.Action;
 import org.eclipse.jface.action.ToolBarManager;
 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.jface.viewers.CheckStateChangedEvent;
 import org.eclipse.jface.viewers.ICheckStateListener;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.ITreeContentProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;

 import org.eclipse.ui.help.WorkbenchHelp;
 import org.eclipse.ui.part.PageBook;

 import org.eclipse.ltk.core.refactoring.Change;
 import org.eclipse.ltk.core.refactoring.CompositeChange;
 import org.eclipse.ltk.core.refactoring.RefactoringStatus;
 import org.eclipse.ltk.internal.ui.refactoring.util.ViewerPane;
 import org.eclipse.ltk.ui.refactoring.ChangePreviewViewerInput;
 import org.eclipse.ltk.ui.refactoring.IChangePreviewViewer;
 import org.eclipse.ltk.ui.refactoring.RefactoringWizard;
 import org.eclipse.ltk.ui.refactoring.RefactoringWizardPage;

 /**
  * Presents the changes made by the refactoring.
  * Consists of a tree of changes and a compare viewer that shows the differences.
  */
 public class PreviewWizardPage extends RefactoringWizardPage implements IPreviewWizardPage {

 	private static class NullPreviewer implements IChangePreviewViewer {
 		private Label fLabel;
 		public void createControl(Composite parent) {
 			fLabel= new Label(parent, SWT.CENTER | SWT.FLAT);
 			fLabel.setText(RefactoringUIMessages.getString("PreviewWizardPage.no_preview")); //$NON-NLS-1$
 		}
 		public void refresh() {
 		}
 		public Control getControl() {
 			return fLabel;
 		}
 		public void setInput(ChangePreviewViewerInput input) {
 		}
 	}

 	private class NextChange extends Action {
 		public NextChange() {
 			setImageDescriptor(CompareUI.DESC_ETOOL_NEXT);
 			setDisabledImageDescriptor(CompareUI.DESC_DTOOL_NEXT);
 			setHoverImageDescriptor(CompareUI.DESC_CTOOL_NEXT);
 			setToolTipText(RefactoringUIMessages.getString("PreviewWizardPage.next_Change")); //$NON-NLS-1$
 			WorkbenchHelp.setHelp(this, IRefactoringHelpContextIds.NEXT_CHANGE_ACTION);
 		}
 		public void run() {
 			fTreeViewer.revealNext();
 		}
 	}

 	private class PreviousChange extends Action {
 		public PreviousChange() {
 			setImageDescriptor(CompareUI.DESC_ETOOL_PREV);
 			setDisabledImageDescriptor(CompareUI.DESC_DTOOL_PREV);
 			setHoverImageDescriptor(CompareUI.DESC_CTOOL_PREV);
 			setToolTipText(RefactoringUIMessages.getString("PreviewWizardPage.previous_Change")); //$NON-NLS-1$
 			WorkbenchHelp.setHelp(this, IRefactoringHelpContextIds.PREVIOUS_CHANGE_ACTION);
 		}
 		public void run() {
 			fTreeViewer.revealPrevious();
 		}
 	}

 	private Change fChange;
 	private CompositeChange fTreeViewerInputChange;
 	private ChangeElement fCurrentSelection;
 	private PageBook fPageContainer;
 	private Control fStandardPage;
 	private Control fNullPage;
 	private ChangeElementTreeViewer fTreeViewer;
 	private PageBook fPreviewContainer;
 	private ChangePreviewViewerDescriptor fCurrentDescriptor;
 	private IChangePreviewViewer fCurrentPreviewViewer;
 	private IChangePreviewViewer fNullPreviewer;

 	/**
 	 * Creates a new proposed changes wizard page.
 	 */
 	public PreviewWizardPage() {
 		super(PAGE_NAME);
 		setDescription(RefactoringUIMessages.getString("PreviewWizardPage.description")); //$NON-NLS-1$
 	}

 	/**
 	 * Sets the given change. Setting the change initializes the tree viewer with
 	 * the given change.
 	 * @param change the new change.
 	 */
 	public void setChange(Change change) {
 		if (fChange == change)
 			return;

 		fChange= change;
 		if (fChange instanceof CompositeChange) {
 			fTreeViewerInputChange= (CompositeChange)fChange;
 		} else {
 			fTreeViewerInputChange= new CompositeChange("Dummy Change"); //$NON-NLS-1$
 			fTreeViewerInputChange.add(fChange);
 		}
 		setTreeViewerInput();
 	}

 	/**
 	 * Creates the tree viewer to present the hierarchy of changes. Subclasses may override
 	 * to create their own custom tree viewer.
 	 *
 	 * @param parent the tree viewer's parent
 	 *
 	 * @return the tree viewer to present the hierarchy of changes
 	 */
 	protected ChangeElementTreeViewer createTreeViewer(Composite parent) {
 		return new ChangeElementTreeViewer(parent);
 	}

 	/**
 	 * Creates the content provider used to fill the tree of changes. Subclasses may override
 	 * to create their own custom tree content provider.
 	 *
 	 * @return the tree content provider used to fill the tree of changes
 	 */
 	protected ITreeContentProvider createTreeContentProvider() {
 		return new ChangeElementContentProvider();
 	}

 	/**
 	 * Creates the label provider used to render the tree of changes. Subclasses may override
 	 * to create their own custom label provider.
 	 *
 	 * @return the label provider used to render the tree of changes
 	 */
 	protected ILabelProvider createTreeLabelProvider() {
 		// return new ChangeElementLabelProvider(JavaElementLabelProvider.SHOW_DEFAULT | JavaElementLabelProvider.SHOW_SMALL_ICONS);
 		return new ChangeElementLabelProvider();
 	}

 	/* (non-JavaDoc)
 	 * Method defined in RefactoringWizardPage
 	 */
 	protected boolean performFinish() {
 		UIPerformChangeOperation operation= new UIPerformChangeOperation(getShell().getDisplay(), fChange, getContainer());
 		FinishResult result= getRefactoringWizard().internalPerformFinish(InternalAPI.INSTANCE, operation);
 		if (result.isException())
 			return true;
 		if (result.isInterrupted())
 			return false;
 		RefactoringStatus fValidationStatus= operation.getValidationStatus();
 		if (fValidationStatus != null && fValidationStatus.hasFatalError()) {
 			RefactoringWizard wizard= getRefactoringWizard();
 			MessageDialog.openError(wizard.getShell(), wizard.getWindowTitle(),
 				RefactoringUIMessages.getFormattedString(
 					"RefactoringUI.cannot_execute", //$NON-NLS-1$
 					fValidationStatus.getMessageMatchingSeverity(RefactoringStatus.FATAL)));
 			return true;
 		}
 		return true;
 	}

 	/* (non-JavaDoc)
 	 * Method defined in IWizardPage
 	 */
 	public boolean canFlipToNextPage() {
 		return false;
 	}

 	/* (Non-JavaDoc)
 	 * Method defined in IWizardPage
 	 */
 	public void createControl(Composite parent) {
 		initializeDialogUnits(parent);
 		fPageContainer= new PageBook(parent, SWT.NONE);
 		fStandardPage= createStandardPreviewPage(fPageContainer);
 		fNullPage= createNullPage(fPageContainer);
 		setControl(fPageContainer);
 		WorkbenchHelp.setHelp(getControl(), IRefactoringHelpContextIds.REFACTORING_PREVIEW_WIZARD_PAGE);
 	}

 	private Composite createStandardPreviewPage(Composite parent) {
 		// XXX The composite is needed to limit the width of the SashForm. See http://bugs.eclipse.org/bugs/show_bug.cgi?id=6854
 		Composite result= new Composite(parent, SWT.NONE);
 		GridLayout layout= new GridLayout();
 		layout.marginHeight= 0; layout.marginWidth= 0;
 		result.setLayout(layout);

 		SashForm sashForm= new SashForm(result, SWT.VERTICAL);

 		ViewerPane pane= new ViewerPane(sashForm, SWT.BORDER | SWT.FLAT);
 		pane.setText(RefactoringUIMessages.getString("PreviewWizardPage.changes")); //$NON-NLS-1$
 		ToolBarManager tbm= pane.getToolBarManager();
 		tbm.add(new NextChange());
 		tbm.add(new PreviousChange());
 		tbm.update(true);

 		fTreeViewer= createTreeViewer(pane);
 		fTreeViewer.setContentProvider(createTreeContentProvider());
 		fTreeViewer.setLabelProvider(createTreeLabelProvider());
 		fTreeViewer.addSelectionChangedListener(createSelectionChangedListener());
 		fTreeViewer.addCheckStateListener(createCheckStateListener());
 		pane.setContent(fTreeViewer.getControl());
 		setTreeViewerInput();

 		fPreviewContainer= new PageBook(sashForm, SWT.NONE);
 		fNullPreviewer= new NullPreviewer();
 		fNullPreviewer.createControl(fPreviewContainer);
 		fPreviewContainer.showPage(fNullPreviewer.getControl());
 		fCurrentPreviewViewer= fNullPreviewer;
 		fCurrentDescriptor= null;

 		sashForm.setWeights(new int[]{33, 67});
 		GridData gd= new GridData(GridData.FILL_BOTH);
 		gd.widthHint= convertWidthInCharsToPixels(80);
 		sashForm.setLayoutData(gd);
 		Dialog.applyDialogFont(result);
 		return result;
 	}

 	private Control createNullPage(Composite parent) {
 		Composite result= new Composite(parent, SWT.NONE);
 		GridLayout layout= new GridLayout();
 		layout.marginWidth = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_MARGIN);
 		layout.marginHeight = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_MARGIN);
 		result.setLayout(layout);
 		Label label= new Label(result, SWT.CENTER);
 		label.setText(RefactoringUIMessages.getString("PreviewWizardPage.no_source_code_change")); //$NON-NLS-1$
 		label.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
 		Dialog.applyDialogFont(result);
 		return result;
 	}

 	/* (Non-JavaDoc)
 	 * Method defined in IWizardPage
 	 */
 	public void setVisible(boolean visible) {
 		fCurrentSelection= null;
 		if (hasChanges()) {
 			fPageContainer.showPage(fStandardPage);
 			ChangeElement treeViewerInput= (ChangeElement)fTreeViewer.getInput();
 			if (visible && treeViewerInput != null) {
 				IStructuredSelection selection= (IStructuredSelection)fTreeViewer.getSelection();
 				if (selection.isEmpty()) {
 					ITreeContentProvider provider= (ITreeContentProvider)fTreeViewer.getContentProvider();
 					ChangeElement element= getFirstNonCompositeChange(provider, treeViewerInput);
 					if (element != null) {
 						if (getRefactoringWizard().internalGetExpandFirstNode(InternalAPI.INSTANCE)) {
 							Object[] subElements= provider.getElements(element);
 							if (subElements != null && subElements.length > 0) {
 								fTreeViewer.expandToLevel(element, 999);
 							}
 						}
 						fTreeViewer.setSelection(new StructuredSelection(element));
 					}
 				}
 			}
 			super.setVisible(visible);
 			fTreeViewer.getControl().setFocus();
 		} else {
 			fPageContainer.showPage(fNullPage);
 			super.setVisible(visible);
 		}
 		getRefactoringWizard().internalSetPreviewShown(InternalAPI.INSTANCE, visible);
 	}

 	private ChangeElement getFirstNonCompositeChange(ITreeContentProvider provider, ChangeElement input) {
 		ChangeElement focus= input;
 		Change change= input.getChange();
 		while (change != null && change instanceof CompositeChange) {
 			ChangeElement[] children= (ChangeElement[])provider.getElements(focus);
 			if (children != null && children.length > 0) {
 				focus= children[0];
 				change= focus.getChange();
 			}
 		}
 		return focus;
 	}

 	private void setTreeViewerInput() {
 		if (fTreeViewer == null)
 			return;
 		ChangeElement input= null;
 		if (fTreeViewerInputChange != null) {
 			input= new DefaultChangeElement(null, fTreeViewerInputChange);
 		}
 		fTreeViewer.setInput(input);
 	}

 	private ICheckStateListener createCheckStateListener() {
 		return new ICheckStateListener() {
 			public void checkStateChanged(CheckStateChangedEvent event){
 				ChangeElement element= (ChangeElement)event.getElement();
 				if (isChild(fCurrentSelection, element) || isChild(element, fCurrentSelection)) {
 					showPreview(fCurrentSelection);
 				}
 			}
 			private boolean isChild(ChangeElement element, ChangeElement child) {
 				while (child != null) {
 					if (child == element)
 						return true;
 					child= child.getParent();
 				}
 				return false;
 			}
 		};
 	}

 	private ISelectionChangedListener createSelectionChangedListener() {
 		return new ISelectionChangedListener(){
 			public void selectionChanged(SelectionChangedEvent event) {
 				IStructuredSelection sel= (IStructuredSelection) event.getSelection();
 				if (sel.size() == 1) {
 					ChangeElement newSelection= (ChangeElement)sel.getFirstElement();
 					if (newSelection != fCurrentSelection) {
 						fCurrentSelection= newSelection;
 						showPreview(newSelection);
 					}
 				} else {
 					showPreview(null);
 				}
 			}
 		};
 	}

 	private void showPreview(ChangeElement element) {
 		try {
 			if (element == null) {
 				showNullPreviewer();
 			} else {
 				ChangePreviewViewerDescriptor descriptor= element.getChangePreviewViewerDescriptor();
 				if (fCurrentDescriptor != descriptor) {
 					IChangePreviewViewer newViewer;
 					if (descriptor != null) {
 						newViewer= descriptor.createViewer();
 						newViewer.createControl(fPreviewContainer);
 					} else {
 						newViewer= fNullPreviewer;
 					}
 					fCurrentDescriptor= descriptor;
 					element.feedInput(newViewer);
 					if (fCurrentPreviewViewer != null && fCurrentPreviewViewer != fNullPreviewer)
 						fCurrentPreviewViewer.getControl().dispose();
 					fCurrentPreviewViewer= newViewer;
 					fPreviewContainer.showPage(fCurrentPreviewViewer.getControl());
 				} else {
 					element.feedInput(fCurrentPreviewViewer);
 				}
 			}
 		} catch (CoreException e) {
 			showNullPreviewer();
 			ExceptionHandler.handle(e, getShell(),
 						RefactoringUIMessages.getString("PreviewWizardPage.refactoring"), //$NON-NLS-1$
 						RefactoringUIMessages.getString("PreviewWizardPage.Internal_error")); //$NON-NLS-1$
 		}
 	}

 	private void showNullPreviewer() {
 		fCurrentDescriptor= null;
 		fCurrentPreviewViewer= fNullPreviewer;
 		fPreviewContainer.showPage(fCurrentPreviewViewer.getControl());
 	}

 	/**
 	 * Returns <code>true</code> if the preview page will show any changes when
 	 * it becomes visibile. Otherwise <code>false</code> is returned.
 	 *
 	 * @return whether the preview has changes or not
 	 */
 	public boolean hasChanges() {
 		if (fChange == null)
 			return false;
 		if (fChange instanceof CompositeChange)
 			return ((CompositeChange)fChange).getChildren().length > 0;
 		return true;
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2004 IBM Corporation and others.
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Common Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/cpl-v10.html
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.ltk.internal.ui.refactoring;

	import org.eclipse.compare.CompareUI;

	import org.eclipse.core.runtime.CoreException;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.SashForm;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Label;

	import org.eclipse.jface.action.Action;
	import org.eclipse.jface.action.ToolBarManager;
	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.MessageDialog;
	import org.eclipse.jface.viewers.CheckStateChangedEvent;
	import org.eclipse.jface.viewers.ICheckStateListener;
	import org.eclipse.jface.viewers.ILabelProvider;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.ITreeContentProvider;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.StructuredSelection;

	import org.eclipse.ui.help.WorkbenchHelp;
	import org.eclipse.ui.part.PageBook;

	import org.eclipse.ltk.core.refactoring.Change;
	import org.eclipse.ltk.core.refactoring.CompositeChange;
	import org.eclipse.ltk.core.refactoring.RefactoringStatus;
	import org.eclipse.ltk.internal.ui.refactoring.util.ViewerPane;
	import org.eclipse.ltk.ui.refactoring.ChangePreviewViewerInput;
	import org.eclipse.ltk.ui.refactoring.IChangePreviewViewer;
	import org.eclipse.ltk.ui.refactoring.RefactoringWizard;
	import org.eclipse.ltk.ui.refactoring.RefactoringWizardPage;

	/**
	* Presents the changes made by the refactoring.
	* Consists of a tree of changes and a compare viewer that shows the differences.
	*/
	public class PreviewWizardPage extends RefactoringWizardPage implements IPreviewWizardPage {

	private static class NullPreviewer implements IChangePreviewViewer {
	private Label fLabel;
	public void createControl(Composite parent) {
	fLabel= new Label(parent, SWT.CENTER \| SWT.FLAT);
	fLabel.setText(RefactoringUIMessages.getString("PreviewWizardPage.no_preview")); //$NON-NLS-1$
	}
	public void refresh() {
	}
	public Control getControl() {
	return fLabel;
	}
	public void setInput(ChangePreviewViewerInput input) {
	}
	}

	private class NextChange extends Action {
	public NextChange() {
	setImageDescriptor(CompareUI.DESC_ETOOL_NEXT);
	setDisabledImageDescriptor(CompareUI.DESC_DTOOL_NEXT);
	setHoverImageDescriptor(CompareUI.DESC_CTOOL_NEXT);
	setToolTipText(RefactoringUIMessages.getString("PreviewWizardPage.next_Change")); //$NON-NLS-1$
	WorkbenchHelp.setHelp(this, IRefactoringHelpContextIds.NEXT_CHANGE_ACTION);
	}
	public void run() {
	fTreeViewer.revealNext();
	}
	}

	private class PreviousChange extends Action {
	public PreviousChange() {
	setImageDescriptor(CompareUI.DESC_ETOOL_PREV);
	setDisabledImageDescriptor(CompareUI.DESC_DTOOL_PREV);
	setHoverImageDescriptor(CompareUI.DESC_CTOOL_PREV);
	setToolTipText(RefactoringUIMessages.getString("PreviewWizardPage.previous_Change")); //$NON-NLS-1$
	WorkbenchHelp.setHelp(this, IRefactoringHelpContextIds.PREVIOUS_CHANGE_ACTION);
	}
	public void run() {
	fTreeViewer.revealPrevious();
	}
	}

	private Change fChange;
	private CompositeChange fTreeViewerInputChange;
	private ChangeElement fCurrentSelection;
	private PageBook fPageContainer;
	private Control fStandardPage;
	private Control fNullPage;
	private ChangeElementTreeViewer fTreeViewer;
	private PageBook fPreviewContainer;
	private ChangePreviewViewerDescriptor fCurrentDescriptor;
	private IChangePreviewViewer fCurrentPreviewViewer;
	private IChangePreviewViewer fNullPreviewer;

	/**
	* Creates a new proposed changes wizard page.
	*/
	public PreviewWizardPage() {
	super(PAGE_NAME);
	setDescription(RefactoringUIMessages.getString("PreviewWizardPage.description")); //$NON-NLS-1$
	}

	/**
	* Sets the given change. Setting the change initializes the tree viewer with
	* the given change.
	* @param change the new change.
	*/
	public void setChange(Change change) {
	if (fChange == change)
	return;

	fChange= change;
	if (fChange instanceof CompositeChange) {
	fTreeViewerInputChange= (CompositeChange)fChange;
	} else {
	fTreeViewerInputChange= new CompositeChange("Dummy Change"); //$NON-NLS-1$
	fTreeViewerInputChange.add(fChange);
	}
	setTreeViewerInput();
	}

	/**
	* Creates the tree viewer to present the hierarchy of changes. Subclasses may override
	* to create their own custom tree viewer.
	*
	* @param parent the tree viewer's parent
	*
	* @return the tree viewer to present the hierarchy of changes
	*/
	protected ChangeElementTreeViewer createTreeViewer(Composite parent) {
	return new ChangeElementTreeViewer(parent);
	}

	/**
	* Creates the content provider used to fill the tree of changes. Subclasses may override
	* to create their own custom tree content provider.
	*
	* @return the tree content provider used to fill the tree of changes
	*/
	protected ITreeContentProvider createTreeContentProvider() {
	return new ChangeElementContentProvider();
	}

	/**
	* Creates the label provider used to render the tree of changes. Subclasses may override
	* to create their own custom label provider.
	*
	* @return the label provider used to render the tree of changes
	*/
	protected ILabelProvider createTreeLabelProvider() {
	// return new ChangeElementLabelProvider(JavaElementLabelProvider.SHOW_DEFAULT \| JavaElementLabelProvider.SHOW_SMALL_ICONS);
	return new ChangeElementLabelProvider();
	}

	/* (non-JavaDoc)
	* Method defined in RefactoringWizardPage
	*/
	protected boolean performFinish() {
	UIPerformChangeOperation operation= new UIPerformChangeOperation(getShell().getDisplay(), fChange, getContainer());
	FinishResult result= getRefactoringWizard().internalPerformFinish(InternalAPI.INSTANCE, operation);
	if (result.isException())
	return true;
	if (result.isInterrupted())
	return false;
	RefactoringStatus fValidationStatus= operation.getValidationStatus();
	if (fValidationStatus != null && fValidationStatus.hasFatalError()) {
	RefactoringWizard wizard= getRefactoringWizard();
	MessageDialog.openError(wizard.getShell(), wizard.getWindowTitle(),
	RefactoringUIMessages.getFormattedString(
	"RefactoringUI.cannot_execute", //$NON-NLS-1$
	fValidationStatus.getMessageMatchingSeverity(RefactoringStatus.FATAL)));
	return true;
	}
	return true;
	}

	/* (non-JavaDoc)
	* Method defined in IWizardPage
	*/
	public boolean canFlipToNextPage() {
	return false;
	}

	/* (Non-JavaDoc)
	* Method defined in IWizardPage
	*/
	public void createControl(Composite parent) {
	initializeDialogUnits(parent);
	fPageContainer= new PageBook(parent, SWT.NONE);
	fStandardPage= createStandardPreviewPage(fPageContainer);
	fNullPage= createNullPage(fPageContainer);
	setControl(fPageContainer);
	WorkbenchHelp.setHelp(getControl(), IRefactoringHelpContextIds.REFACTORING_PREVIEW_WIZARD_PAGE);
	}

	private Composite createStandardPreviewPage(Composite parent) {
	// XXX The composite is needed to limit the width of the SashForm. See http://bugs.eclipse.org/bugs/show_bug.cgi?id=6854
	Composite result= new Composite(parent, SWT.NONE);
	GridLayout layout= new GridLayout();
	layout.marginHeight= 0; layout.marginWidth= 0;
	result.setLayout(layout);

	SashForm sashForm= new SashForm(result, SWT.VERTICAL);

	ViewerPane pane= new ViewerPane(sashForm, SWT.BORDER \| SWT.FLAT);
	pane.setText(RefactoringUIMessages.getString("PreviewWizardPage.changes")); //$NON-NLS-1$
	ToolBarManager tbm= pane.getToolBarManager();
	tbm.add(new NextChange());
	tbm.add(new PreviousChange());
	tbm.update(true);

	fTreeViewer= createTreeViewer(pane);
	fTreeViewer.setContentProvider(createTreeContentProvider());
	fTreeViewer.setLabelProvider(createTreeLabelProvider());
	fTreeViewer.addSelectionChangedListener(createSelectionChangedListener());
	fTreeViewer.addCheckStateListener(createCheckStateListener());
	pane.setContent(fTreeViewer.getControl());
	setTreeViewerInput();

	fPreviewContainer= new PageBook(sashForm, SWT.NONE);
	fNullPreviewer= new NullPreviewer();
	fNullPreviewer.createControl(fPreviewContainer);
	fPreviewContainer.showPage(fNullPreviewer.getControl());
	fCurrentPreviewViewer= fNullPreviewer;
	fCurrentDescriptor= null;

	sashForm.setWeights(new int[]{33, 67});
	GridData gd= new GridData(GridData.FILL_BOTH);
	gd.widthHint= convertWidthInCharsToPixels(80);
	sashForm.setLayoutData(gd);
	Dialog.applyDialogFont(result);
	return result;
	}

	private Control createNullPage(Composite parent) {
	Composite result= new Composite(parent, SWT.NONE);
	GridLayout layout= new GridLayout();
	layout.marginWidth = convertHorizontalDLUsToPixels(IDialogConstants.HORIZONTAL_MARGIN);
	layout.marginHeight = convertVerticalDLUsToPixels(IDialogConstants.VERTICAL_MARGIN);
	result.setLayout(layout);
	Label label= new Label(result, SWT.CENTER);
	label.setText(RefactoringUIMessages.getString("PreviewWizardPage.no_source_code_change")); //$NON-NLS-1$
	label.setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
	Dialog.applyDialogFont(result);
	return result;
	}

	/* (Non-JavaDoc)
	* Method defined in IWizardPage
	*/
	public void setVisible(boolean visible) {
	fCurrentSelection= null;
	if (hasChanges()) {
	fPageContainer.showPage(fStandardPage);
	ChangeElement treeViewerInput= (ChangeElement)fTreeViewer.getInput();
	if (visible && treeViewerInput != null) {
	IStructuredSelection selection= (IStructuredSelection)fTreeViewer.getSelection();
	if (selection.isEmpty()) {
	ITreeContentProvider provider= (ITreeContentProvider)fTreeViewer.getContentProvider();
	ChangeElement element= getFirstNonCompositeChange(provider, treeViewerInput);
	if (element != null) {
	if (getRefactoringWizard().internalGetExpandFirstNode(InternalAPI.INSTANCE)) {
	Object[] subElements= provider.getElements(element);
	if (subElements != null && subElements.length > 0) {
	fTreeViewer.expandToLevel(element, 999);
	}
	}
	fTreeViewer.setSelection(new StructuredSelection(element));
	}
	}
	}
	super.setVisible(visible);
	fTreeViewer.getControl().setFocus();
	} else {
	fPageContainer.showPage(fNullPage);
	super.setVisible(visible);
	}
	getRefactoringWizard().internalSetPreviewShown(InternalAPI.INSTANCE, visible);
	}

	private ChangeElement getFirstNonCompositeChange(ITreeContentProvider provider, ChangeElement input) {
	ChangeElement focus= input;
	Change change= input.getChange();
	while (change != null && change instanceof CompositeChange) {
	ChangeElement[] children= (ChangeElement[])provider.getElements(focus);
	if (children != null && children.length > 0) {
	focus= children[0];
	change= focus.getChange();
	}
	}
	return focus;
	}

	private void setTreeViewerInput() {
	if (fTreeViewer == null)
	return;
	ChangeElement input= null;
	if (fTreeViewerInputChange != null) {
	input= new DefaultChangeElement(null, fTreeViewerInputChange);
	}
	fTreeViewer.setInput(input);
	}

	private ICheckStateListener createCheckStateListener() {
	return new ICheckStateListener() {
	public void checkStateChanged(CheckStateChangedEvent event){
	ChangeElement element= (ChangeElement)event.getElement();
	if (isChild(fCurrentSelection, element) \|\| isChild(element, fCurrentSelection)) {
	showPreview(fCurrentSelection);
	}
	}
	private boolean isChild(ChangeElement element, ChangeElement child) {
	while (child != null) {
	if (child == element)
	return true;
	child= child.getParent();
	}
	return false;
	}
	};
	}

	private ISelectionChangedListener createSelectionChangedListener() {
	return new ISelectionChangedListener(){
	public void selectionChanged(SelectionChangedEvent event) {
	IStructuredSelection sel= (IStructuredSelection) event.getSelection();
	if (sel.size() == 1) {
	ChangeElement newSelection= (ChangeElement)sel.getFirstElement();
	if (newSelection != fCurrentSelection) {
	fCurrentSelection= newSelection;
	showPreview(newSelection);
	}
	} else {
	showPreview(null);
	}
	}
	};
	}

	private void showPreview(ChangeElement element) {
	try {
	if (element == null) {
	showNullPreviewer();
	} else {
	ChangePreviewViewerDescriptor descriptor= element.getChangePreviewViewerDescriptor();
	if (fCurrentDescriptor != descriptor) {
	IChangePreviewViewer newViewer;
	if (descriptor != null) {
	newViewer= descriptor.createViewer();
	newViewer.createControl(fPreviewContainer);
	} else {
	newViewer= fNullPreviewer;
	}
	fCurrentDescriptor= descriptor;
	element.feedInput(newViewer);
	if (fCurrentPreviewViewer != null && fCurrentPreviewViewer != fNullPreviewer)
	fCurrentPreviewViewer.getControl().dispose();
	fCurrentPreviewViewer= newViewer;
	fPreviewContainer.showPage(fCurrentPreviewViewer.getControl());
	} else {
	element.feedInput(fCurrentPreviewViewer);
	}
	}
	} catch (CoreException e) {
	showNullPreviewer();
	ExceptionHandler.handle(e, getShell(),
	RefactoringUIMessages.getString("PreviewWizardPage.refactoring"), //$NON-NLS-1$
	RefactoringUIMessages.getString("PreviewWizardPage.Internal_error")); //$NON-NLS-1$
	}
	}

	private void showNullPreviewer() {
	fCurrentDescriptor= null;
	fCurrentPreviewViewer= fNullPreviewer;
	fPreviewContainer.showPage(fCurrentPreviewViewer.getControl());
	}

	/**
	* Returns <code>true</code> if the preview page will show any changes when
	* it becomes visibile. Otherwise <code>false</code> is returned.
	*
	* @return whether the preview has changes or not
	*/
	public boolean hasChanges() {
	if (fChange == null)
	return false;
	if (fChange instanceof CompositeChange)
	return ((CompositeChange)fChange).getChildren().length > 0;
	return true;
	}
	}