org.eclipse.jdt.ui/ui refactoring/org/eclipse/jdt/internal/ui/refactoring/ChangeTypeWizard.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2016 IBM Corporation and others.
  *
  * This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License 2.0
  * which accompanies this distribution, and is available at
  * https://www.eclipse.org/legal/epl-2.0/
  *
  * SPDX-License-Identifier: EPL-2.0
  *
  * Contributors:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.jdt.internal.ui.refactoring;

 import java.lang.reflect.InvocationTargetException;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.graphics.Color;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Display;
 import org.eclipse.swt.widgets.Label;
 import org.eclipse.swt.widgets.Tree;
 import org.eclipse.swt.widgets.TreeItem;

 import org.eclipse.core.runtime.SubProgressMonitor;

 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.operation.IRunnableWithProgress;
 import org.eclipse.jface.viewers.IColorProvider;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.LabelProviderChangedEvent;
 import org.eclipse.jface.viewers.TreeViewer;
 import org.eclipse.jface.wizard.IWizardPage;

 import org.eclipse.ui.PlatformUI;

 import org.eclipse.ltk.ui.refactoring.RefactoringWizard;
 import org.eclipse.ltk.ui.refactoring.UserInputWizardPage;

 import org.eclipse.jdt.core.dom.ITypeBinding;

 import org.eclipse.jdt.internal.corext.refactoring.structure.ChangeTypeRefactoring;
 import org.eclipse.jdt.internal.corext.util.Messages;

 import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
 import org.eclipse.jdt.internal.ui.JavaPlugin;
 import org.eclipse.jdt.internal.core.manipulation.util.BasicElementLabels;
 import org.eclipse.jdt.internal.ui.viewsupport.BindingLabelProvider;


 /**
  * @author tip
  */
 public class ChangeTypeWizard extends RefactoringWizard {

 	private ChangeTypeRefactoring fCT;

 	public ChangeTypeWizard(ChangeTypeRefactoring ref) {
 		super(ref, DIALOG_BASED_USER_INTERFACE);
 		setDefaultPageTitle(RefactoringMessages.ChangeTypeWizard_title);
 		fCT= ref;
 	}

 	/* non java-doc
 	 * @see RefactoringWizard#addUserInputPages
 	 */
 	@Override
 	protected void addUserInputPages(){
 		addPage(new ChangeTypeInputPage());
 	}

 	// For debugging
 	static String print(Collection<ITypeBinding> types){
 		if (types.isEmpty())
 			return "{ }"; //$NON-NLS-1$
 		StringBuilder result = new StringBuilder("{ "); //$NON-NLS-1$
 		for (Iterator<ITypeBinding> it=types.iterator(); it.hasNext(); ){
 			ITypeBinding type= it.next();
 			result.append(type.getQualifiedName());
 			if (it.hasNext()){
 				result.append(", ");  //$NON-NLS-1$
 			} else {
 				result.append(" }"); //$NON-NLS-1$
 			}
 		}
 		return result.toString();
 	}


 	/**
 	 * A JavaElementLabelProvider that supports graying out of invalid types.
 	 */
 	private static class ChangeTypeLabelProvider extends BindingLabelProvider
 										  implements IColorProvider {

 		private Color fGrayColor;
 		/** color -> gray */
 		private HashMap<Image, Image> fGrayImages;

 		public ChangeTypeLabelProvider(){
 			fGrayColor= Display.getCurrent().getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
 			fGrayImages= new HashMap<>();
 		}

 		private Collection<ITypeBinding> fInvalidTypes;

 		public void grayOut(Collection<ITypeBinding> invalidTypes){
 			fInvalidTypes= invalidTypes;
 			/*
 			 * Invalidate all labels. Invalidating only invalid types doesn't
 			 * work since there can be multiple nodes in the tree that
 			 * correspond to the same invalid IType. The TreeViewer only updates
 			 * the label of one of these ITypes and leaves the others in their
 			 * old state.
 			 */
 			fireLabelProviderChanged(new LabelProviderChangedEvent(this));
 		}

 		@Override
 		public Color getForeground(Object element) {
 			if (isInvalid(element))
 				return fGrayColor;
 			else
 				return null;
 		}

 		private boolean isInvalid(Object element) {
 			if (fInvalidTypes == null)
 				return false; // initially, everything is enabled
 			else
 				return fInvalidTypes.contains(element);
 		}

 		@Override
 		public Color getBackground(Object element) {
 			return null;
 		}

 		/*
 		 * @see org.eclipse.jface.viewers.ILabelProvider#getImage(java.lang.Object)
 		 */
 		@Override
 		public Image getImage(Object element) {
 			Image image= super.getImage(element);
 			if (isInvalid(element) && image != null) {
 				Image grayImage= fGrayImages.get(image);
 				if (grayImage == null) {
 					grayImage= new Image(Display.getCurrent(), image, SWT.IMAGE_GRAY);
 					fGrayImages.put(image, grayImage);
 				}
 				return grayImage;
 			} else {
 				return image;
 			}
 		}

 		@Override
 		public void dispose() {
 			for (Image image : fGrayImages.values()) {
 				image.dispose();
 			}
 			fGrayImages.clear();
 			super.dispose();
 		}
 	}

 	private class ChangeTypeInputPage extends UserInputWizardPage{

 		public static final String PAGE_NAME= "ChangeTypeInputPage";//$NON-NLS-1$
 		private final  String MESSAGE= RefactoringMessages.ChangeTypeInputPage_Select_Type;
 		private ChangeTypeLabelProvider fLabelProvider;
 		private TreeViewer fTreeViewer;
 		private boolean fTreeUpdated= false;

 		public ChangeTypeInputPage() {
 			super(PAGE_NAME);
 			setMessage(MESSAGE);
 		}

 		private class ValidTypesTask implements Runnable {
 			private Collection<ITypeBinding> fInvalidTypes;
 			private Collection<ITypeBinding> fValidTypes;
 			@Override
 			public void run() {
 				IRunnableWithProgress runnable= pm -> {
 					pm.beginTask(RefactoringMessages.ChangeTypeWizard_analyzing, 1000);
 					ChangeTypeRefactoring ct= (ChangeTypeRefactoring)ChangeTypeWizard.this.getRefactoring();
 					fInvalidTypes = new HashSet<>();
 					fInvalidTypes.addAll(fCT.getAllSuperTypes(ct.getOriginalType()));
 					fValidTypes= ct.computeValidTypes(new SubProgressMonitor(pm, 950));
 					fInvalidTypes.add(ct.getOriginalType());
 					fInvalidTypes.removeAll(fValidTypes);
 					pm.worked(50);
 					pm.done();
 				};
 				boolean internalError= false;
 				try {
 					getWizard().getContainer().run(true, true, runnable);
 				} catch (InvocationTargetException e) {
 					internalError= true;
 					JavaPlugin.log(e);
 					ChangeTypeInputPage.this.setErrorMessage(RefactoringMessages.ChangeTypeWizard_internalError);
 				} catch (InterruptedException e) {
 					ChangeTypeInputPage.this.setMessage(RefactoringMessages.ChangeTypeWizard_computationInterrupted);
 				}

 				fLabelProvider.grayOut(fInvalidTypes);

 				if (internalError) {
 					setPageComplete(false);
 				} else if (fValidTypes == null || fValidTypes.isEmpty()){
 					ChangeTypeInputPage.this.setErrorMessage(RefactoringMessages.ChangeTypeWizard_declCannotBeChanged);
 					setPageComplete(false);
 				} else {
 					TreeItem selection= getInitialSelection(fValidTypes);
 					fTreeViewer.getTree().setSelection(new TreeItem[]{ selection });
 					setPageComplete(true);
 					ChangeTypeInputPage.this.setMessage(""); //$NON-NLS-1$
 				}
 			}
 		}

 		private TreeItem getInitialSelection(Collection<ITypeBinding> types) {

 			// first, find a most general valid type (there may be more than one)
 			ITypeBinding type= types.iterator().next();
 			for (ITypeBinding other : types) {
 				if (getGeneralizeTypeRefactoring().isSubTypeOf(type, other)){
 					type= other;
 				}
 			}

 			// now find a corresponding TreeItem (there may be more than one)
 			return findItem(fTreeViewer.getTree().getItems(), type);
 		}

 		private TreeItem findItem(TreeItem[] items, ITypeBinding type){
 			for (TreeItem item : items) {
 				if (item.getData().equals(type)) {
 					return item;
 				}
 			}
 			for (TreeItem ti : items) {
 				TreeItem item= findItem(ti.getItems(), type);
 				if (item != null) return item;
 			}
 			return null;
 		}


 		@Override
 		public void createControl(Composite parent) {
 			Composite composite= new Composite(parent, SWT.NONE);
 			setControl(composite);
 			composite.setLayout(new GridLayout());
 			composite.setLayoutData(new GridData());

 			Label label= new Label(composite, SWT.NONE);
 			label.setText(Messages.format(
 					RefactoringMessages.ChangeTypeWizard_pleaseChooseType,
 					((ChangeTypeRefactoring) getRefactoring()).getTarget()));
 			label.setLayoutData(new GridData());

 			addTreeComponent(composite);
 			Dialog.applyDialogFont(composite);
 			PlatformUI.getWorkbench().getHelpSystem().setHelp(getControl(), IJavaHelpContextIds.CHANGE_TYPE_WIZARD_PAGE);
 		}

 		/**
 		 * Tree-viewer that shows the allowable types in a tree view.
 		 * @param parent the parent
 		 */
 		private void addTreeComponent(Composite parent) {
 			fTreeViewer= new TreeViewer(parent, SWT.SINGLE | SWT.BORDER | SWT.V_SCROLL | SWT.H_SCROLL);

 			GridData gd= new GridData(GridData.FILL_BOTH);
 			gd.grabExcessHorizontalSpace= true;
 			gd.grabExcessVerticalSpace= true;
 			Tree tree= fTreeViewer.getTree();
 			Dialog.applyDialogFont(tree);
 			gd.heightHint= tree.getItemHeight() * 12;
 			tree.setLayoutData(gd);

 			fTreeViewer.setContentProvider(new ChangeTypeContentProvider(((ChangeTypeRefactoring)getRefactoring())));
 			fLabelProvider= new ChangeTypeLabelProvider();
 			fTreeViewer.setLabelProvider(fLabelProvider);
 			ISelectionChangedListener listener= event -> {
 				IStructuredSelection selection= (IStructuredSelection)event.getSelection();
 				typeSelected((ITypeBinding)selection.getFirstElement());
 			};
 			fTreeViewer.addSelectionChangedListener(listener);
 			fTreeViewer.setInput(new ChangeTypeContentProvider.RootType(getGeneralizeTypeRefactoring().getOriginalType()));
 			fTreeViewer.expandToLevel(10);
 		}

 		private void typeSelected(ITypeBinding type) {
 			boolean isValid= getGeneralizeTypeRefactoring().getValidTypes().contains(type);
 			ChangeTypeInputPage.this.setPageComplete(isValid);
 			if (isValid) {
 				ChangeTypeInputPage.this.setMessage(""); //$NON-NLS-1$
 			} else {
 				if (getGeneralizeTypeRefactoring().getOriginalType().equals(type)) {
 					ChangeTypeInputPage.this.setMessage(Messages.format(
 						RefactoringMessages.ChangeTypeWizard_with_itself, BasicElementLabels.getJavaElementName(type.getName())));

 				} else {
 					ChangeTypeInputPage.this.setMessage(Messages.format(
 						RefactoringMessages.ChangeTypeWizard_grayed_types,
 						new Object[] {BasicElementLabels.getJavaElementName(type.getName()), BasicElementLabels.getJavaElementName(getGeneralizeTypeRefactoring().getOriginalType().getName())}));
 				}
 			}
 		}

 		private ChangeTypeRefactoring getGeneralizeTypeRefactoring(){
 			return (ChangeTypeRefactoring)getRefactoring();
 		}
 		/*
 		 * @see org.eclipse.jface.wizard.IWizardPage#getNextPage()
 		 */
 		@Override
 		public IWizardPage getNextPage() {
 			initializeRefactoring();
 			return super.getNextPage();
 		}

 		private ITypeBinding getSelectedType() {
 			IStructuredSelection ss= (IStructuredSelection)fTreeViewer.getSelection();
 			return (ITypeBinding)ss.getFirstElement();
 		}

 		/*
 		 * @see org.eclipse.jdt.internal.ui.refactoring.RefactoringWizardPage#performFinish()
 		 */
 		@Override
 		public boolean performFinish(){
 			initializeRefactoring();
 			return super.performFinish();
 		}

 		private void initializeRefactoring() {
 			getGeneralizeTypeRefactoring().setSelectedType(getSelectedType());
 		}

 		/*
 		 * @see org.eclipse.jface.dialogs.IDialogPage#dispose()
 		 */
 		@Override
 		public void dispose() {
 			fTreeViewer= null;
 			super.dispose();
 		}

 		@Override
 		public void setVisible(boolean visible) {
 			super.setVisible(visible);
 			if (visible && fTreeViewer != null)
 				fTreeViewer.getTree().setFocus();
 				if (!fTreeUpdated){
 					fTreeViewer.getTree().getDisplay().asyncExec(new ValidTypesTask());
 					fTreeUpdated= true;
 				}
 		}
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2016 IBM Corporation and others.
	*
	* This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License 2.0
	* which accompanies this distribution, and is available at
	* https://www.eclipse.org/legal/epl-2.0/
	*
	* SPDX-License-Identifier: EPL-2.0
	*
	* Contributors:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.jdt.internal.ui.refactoring;

	import java.lang.reflect.InvocationTargetException;
	import java.util.Collection;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Iterator;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.graphics.Color;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Display;
	import org.eclipse.swt.widgets.Label;
	import org.eclipse.swt.widgets.Tree;
	import org.eclipse.swt.widgets.TreeItem;

	import org.eclipse.core.runtime.SubProgressMonitor;

	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.operation.IRunnableWithProgress;
	import org.eclipse.jface.viewers.IColorProvider;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.LabelProviderChangedEvent;
	import org.eclipse.jface.viewers.TreeViewer;
	import org.eclipse.jface.wizard.IWizardPage;

	import org.eclipse.ui.PlatformUI;

	import org.eclipse.ltk.ui.refactoring.RefactoringWizard;
	import org.eclipse.ltk.ui.refactoring.UserInputWizardPage;

	import org.eclipse.jdt.core.dom.ITypeBinding;

	import org.eclipse.jdt.internal.corext.refactoring.structure.ChangeTypeRefactoring;
	import org.eclipse.jdt.internal.corext.util.Messages;

	import org.eclipse.jdt.internal.ui.IJavaHelpContextIds;
	import org.eclipse.jdt.internal.ui.JavaPlugin;
	import org.eclipse.jdt.internal.core.manipulation.util.BasicElementLabels;
	import org.eclipse.jdt.internal.ui.viewsupport.BindingLabelProvider;


	/**
	* @author tip
	*/
	public class ChangeTypeWizard extends RefactoringWizard {

	private ChangeTypeRefactoring fCT;

	public ChangeTypeWizard(ChangeTypeRefactoring ref) {
	super(ref, DIALOG_BASED_USER_INTERFACE);
	setDefaultPageTitle(RefactoringMessages.ChangeTypeWizard_title);
	fCT= ref;
	}

	/* non java-doc
	* @see RefactoringWizard#addUserInputPages
	*/
	@Override
	protected void addUserInputPages(){
	addPage(new ChangeTypeInputPage());
	}

	// For debugging
	static String print(Collection<ITypeBinding> types){
	if (types.isEmpty())
	return "{ }"; //$NON-NLS-1$
	StringBuilder result = new StringBuilder("{ "); //$NON-NLS-1$
	for (Iterator<ITypeBinding> it=types.iterator(); it.hasNext(); ){
	ITypeBinding type= it.next();
	result.append(type.getQualifiedName());
	if (it.hasNext()){
	result.append(", "); //$NON-NLS-1$
	} else {
	result.append(" }"); //$NON-NLS-1$
	}
	}
	return result.toString();
	}


	/**
	* A JavaElementLabelProvider that supports graying out of invalid types.
	*/
	private static class ChangeTypeLabelProvider extends BindingLabelProvider
	implements IColorProvider {

	private Color fGrayColor;
	/** color -> gray */
	private HashMap<Image, Image> fGrayImages;

	public ChangeTypeLabelProvider(){
	fGrayColor= Display.getCurrent().getSystemColor(SWT.COLOR_WIDGET_NORMAL_SHADOW);
	fGrayImages= new HashMap<>();
	}

	private Collection<ITypeBinding> fInvalidTypes;

	public void grayOut(Collection<ITypeBinding> invalidTypes){
	fInvalidTypes= invalidTypes;
	/*
	* Invalidate all labels. Invalidating only invalid types doesn't
	* work since there can be multiple nodes in the tree that
	* correspond to the same invalid IType. The TreeViewer only updates
	* the label of one of these ITypes and leaves the others in their
	* old state.
	*/
	fireLabelProviderChanged(new LabelProviderChangedEvent(this));
	}

	@Override
	public Color getForeground(Object element) {
	if (isInvalid(element))
	return fGrayColor;
	else
	return null;
	}

	private boolean isInvalid(Object element) {
	if (fInvalidTypes == null)
	return false; // initially, everything is enabled
	else
	return fInvalidTypes.contains(element);
	}

	@Override
	public Color getBackground(Object element) {
	return null;
	}

	/*
	* @see org.eclipse.jface.viewers.ILabelProvider#getImage(java.lang.Object)
	*/
	@Override
	public Image getImage(Object element) {
	Image image= super.getImage(element);
	if (isInvalid(element) && image != null) {
	Image grayImage= fGrayImages.get(image);
	if (grayImage == null) {
	grayImage= new Image(Display.getCurrent(), image, SWT.IMAGE_GRAY);
	fGrayImages.put(image, grayImage);
	}
	return grayImage;
	} else {
	return image;
	}
	}

	@Override
	public void dispose() {
	for (Image image : fGrayImages.values()) {
	image.dispose();
	}
	fGrayImages.clear();
	super.dispose();
	}
	}

	private class ChangeTypeInputPage extends UserInputWizardPage{

	public static final String PAGE_NAME= "ChangeTypeInputPage";//$NON-NLS-1$
	private final String MESSAGE= RefactoringMessages.ChangeTypeInputPage_Select_Type;
	private ChangeTypeLabelProvider fLabelProvider;
	private TreeViewer fTreeViewer;
	private boolean fTreeUpdated= false;

	public ChangeTypeInputPage() {
	super(PAGE_NAME);
	setMessage(MESSAGE);
	}

	private class ValidTypesTask implements Runnable {
	private Collection<ITypeBinding> fInvalidTypes;
	private Collection<ITypeBinding> fValidTypes;
	@Override
	public void run() {
	IRunnableWithProgress runnable= pm -> {
	pm.beginTask(RefactoringMessages.ChangeTypeWizard_analyzing, 1000);
	ChangeTypeRefactoring ct= (ChangeTypeRefactoring)ChangeTypeWizard.this.getRefactoring();
	fInvalidTypes = new HashSet<>();
	fInvalidTypes.addAll(fCT.getAllSuperTypes(ct.getOriginalType()));
	fValidTypes= ct.computeValidTypes(new SubProgressMonitor(pm, 950));
	fInvalidTypes.add(ct.getOriginalType());
	fInvalidTypes.removeAll(fValidTypes);
	pm.worked(50);
	pm.done();
	};
	boolean internalError= false;
	try {
	getWizard().getContainer().run(true, true, runnable);
	} catch (InvocationTargetException e) {
	internalError= true;
	JavaPlugin.log(e);
	ChangeTypeInputPage.this.setErrorMessage(RefactoringMessages.ChangeTypeWizard_internalError);
	} catch (InterruptedException e) {
	ChangeTypeInputPage.this.setMessage(RefactoringMessages.ChangeTypeWizard_computationInterrupted);
	}

	fLabelProvider.grayOut(fInvalidTypes);

	if (internalError) {
	setPageComplete(false);
	} else if (fValidTypes == null \|\| fValidTypes.isEmpty()){
	ChangeTypeInputPage.this.setErrorMessage(RefactoringMessages.ChangeTypeWizard_declCannotBeChanged);
	setPageComplete(false);
	} else {
	TreeItem selection= getInitialSelection(fValidTypes);
	fTreeViewer.getTree().setSelection(new TreeItem[]{ selection });
	setPageComplete(true);
	ChangeTypeInputPage.this.setMessage(""); //$NON-NLS-1$
	}
	}
	}

	private TreeItem getInitialSelection(Collection<ITypeBinding> types) {

	// first, find a most general valid type (there may be more than one)
	ITypeBinding type= types.iterator().next();
	for (ITypeBinding other : types) {
	if (getGeneralizeTypeRefactoring().isSubTypeOf(type, other)){
	type= other;
	}
	}

	// now find a corresponding TreeItem (there may be more than one)
	return findItem(fTreeViewer.getTree().getItems(), type);
	}

	private TreeItem findItem(TreeItem[] items, ITypeBinding type){
	for (TreeItem item : items) {
	if (item.getData().equals(type)) {
	return item;
	}
	}
	for (TreeItem ti : items) {
	TreeItem item= findItem(ti.getItems(), type);
	if (item != null) return item;
	}
	return null;
	}


	@Override
	public void createControl(Composite parent) {
	Composite composite= new Composite(parent, SWT.NONE);
	setControl(composite);
	composite.setLayout(new GridLayout());
	composite.setLayoutData(new GridData());

	Label label= new Label(composite, SWT.NONE);
	label.setText(Messages.format(
	RefactoringMessages.ChangeTypeWizard_pleaseChooseType,
	((ChangeTypeRefactoring) getRefactoring()).getTarget()));
	label.setLayoutData(new GridData());

	addTreeComponent(composite);
	Dialog.applyDialogFont(composite);
	PlatformUI.getWorkbench().getHelpSystem().setHelp(getControl(), IJavaHelpContextIds.CHANGE_TYPE_WIZARD_PAGE);
	}

	/**
	* Tree-viewer that shows the allowable types in a tree view.
	* @param parent the parent
	*/
	private void addTreeComponent(Composite parent) {
	fTreeViewer= new TreeViewer(parent, SWT.SINGLE \| SWT.BORDER \| SWT.V_SCROLL \| SWT.H_SCROLL);

	GridData gd= new GridData(GridData.FILL_BOTH);
	gd.grabExcessHorizontalSpace= true;
	gd.grabExcessVerticalSpace= true;
	Tree tree= fTreeViewer.getTree();
	Dialog.applyDialogFont(tree);
	gd.heightHint= tree.getItemHeight() * 12;
	tree.setLayoutData(gd);

	fTreeViewer.setContentProvider(new ChangeTypeContentProvider(((ChangeTypeRefactoring)getRefactoring())));
	fLabelProvider= new ChangeTypeLabelProvider();
	fTreeViewer.setLabelProvider(fLabelProvider);
	ISelectionChangedListener listener= event -> {
	IStructuredSelection selection= (IStructuredSelection)event.getSelection();
	typeSelected((ITypeBinding)selection.getFirstElement());
	};
	fTreeViewer.addSelectionChangedListener(listener);
	fTreeViewer.setInput(new ChangeTypeContentProvider.RootType(getGeneralizeTypeRefactoring().getOriginalType()));
	fTreeViewer.expandToLevel(10);
	}

	private void typeSelected(ITypeBinding type) {
	boolean isValid= getGeneralizeTypeRefactoring().getValidTypes().contains(type);
	ChangeTypeInputPage.this.setPageComplete(isValid);
	if (isValid) {
	ChangeTypeInputPage.this.setMessage(""); //$NON-NLS-1$
	} else {
	if (getGeneralizeTypeRefactoring().getOriginalType().equals(type)) {
	ChangeTypeInputPage.this.setMessage(Messages.format(
	RefactoringMessages.ChangeTypeWizard_with_itself, BasicElementLabels.getJavaElementName(type.getName())));

	} else {
	ChangeTypeInputPage.this.setMessage(Messages.format(
	RefactoringMessages.ChangeTypeWizard_grayed_types,
	new Object[] {BasicElementLabels.getJavaElementName(type.getName()), BasicElementLabels.getJavaElementName(getGeneralizeTypeRefactoring().getOriginalType().getName())}));
	}
	}
	}

	private ChangeTypeRefactoring getGeneralizeTypeRefactoring(){
	return (ChangeTypeRefactoring)getRefactoring();
	}
	/*
	* @see org.eclipse.jface.wizard.IWizardPage#getNextPage()
	*/
	@Override
	public IWizardPage getNextPage() {
	initializeRefactoring();
	return super.getNextPage();
	}

	private ITypeBinding getSelectedType() {
	IStructuredSelection ss= (IStructuredSelection)fTreeViewer.getSelection();
	return (ITypeBinding)ss.getFirstElement();
	}

	/*
	* @see org.eclipse.jdt.internal.ui.refactoring.RefactoringWizardPage#performFinish()
	*/
	@Override
	public boolean performFinish(){
	initializeRefactoring();
	return super.performFinish();
	}

	private void initializeRefactoring() {
	getGeneralizeTypeRefactoring().setSelectedType(getSelectedType());
	}

	/*
	* @see org.eclipse.jface.dialogs.IDialogPage#dispose()
	*/
	@Override
	public void dispose() {
	fTreeViewer= null;
	super.dispose();
	}

	@Override
	public void setVisible(boolean visible) {
	super.setVisible(visible);
	if (visible && fTreeViewer != null)
	fTreeViewer.getTree().setFocus();
	if (!fTreeUpdated){
	fTreeViewer.getTree().getDisplay().asyncExec(new ValidTypesTask());
	fTreeUpdated= true;
	}
	}
	}
	}