org.eclipse.jdt.ui/ui/org/eclipse/jdt/internal/ui/preferences/FoldingConfigurationBlock.java - jdt/eclipse.jdt.ui - Git at Google

 /*******************************************************************************
  * Copyright (c) 2000, 2005 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
  *******************************************************************************/

 package org.eclipse.jdt.internal.ui.preferences;

 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.Iterator;
 import java.util.Map;

 import org.eclipse.core.runtime.CoreException;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.core.runtime.Status;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.custom.StackLayout;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.layout.FillLayout;
 import org.eclipse.swt.layout.GridData;
 import org.eclipse.swt.layout.GridLayout;
 import org.eclipse.swt.widgets.Button;
 import org.eclipse.swt.widgets.Combo;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Control;
 import org.eclipse.swt.widgets.Label;

 import org.eclipse.jface.dialogs.Dialog;
 import org.eclipse.jface.viewers.ComboViewer;
 import org.eclipse.jface.viewers.ISelectionChangedListener;
 import org.eclipse.jface.viewers.IStructuredContentProvider;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.SelectionChangedEvent;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.viewers.Viewer;

 import org.eclipse.jface.text.Assert;

 import org.eclipse.jdt.internal.corext.util.Messages;

 import org.eclipse.jdt.ui.PreferenceConstants;
 import org.eclipse.jdt.ui.text.folding.IJavaFoldingPreferenceBlock;

 import org.eclipse.jdt.internal.ui.JavaPlugin;
 import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderDescriptor;
 import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderRegistry;
 import org.eclipse.jdt.internal.ui.util.PixelConverter;

 /**
  * Configures Java Editor folding preferences.
  *
  * @since 3.0
  */
 class FoldingConfigurationBlock implements IPreferenceConfigurationBlock {

 	private static class ErrorPreferences implements IJavaFoldingPreferenceBlock {
 		private String fMessage;

 		protected ErrorPreferences(String message) {
 			fMessage= message;
 		}

 		/*
 		 * @see org.eclipse.jdt.internal.ui.text.folding.IJavaFoldingPreferences#createControl(org.eclipse.swt.widgets.Group)
 		 */
 		public Control createControl(Composite composite) {
 			Composite inner= new Composite(composite, SWT.NONE);
 			inner.setLayout(new FillLayout(SWT.VERTICAL));

 			Label label= new Label(inner, SWT.CENTER);
 			label.setText(fMessage);

 			return inner;
 		}

 		public void initialize() {
 		}

 		public void performOk() {
 		}

 		public void performDefaults() {
 		}

 		public void dispose() {
 		}

 	}

 	/** The overlay preference store. */
 	private final OverlayPreferenceStore fStore;

 	/* The controls */
 	private Combo fProviderCombo;
 	private Button fFoldingCheckbox;
 	private ComboViewer fProviderViewer;
 	private Composite fGroup;
 	private StackLayout fStackLayout;

 	/* the model */
 	private final Map fProviderDescriptors;
 	private final Map fProviderPreferences;
 	private final Map fProviderControls;


 	public FoldingConfigurationBlock(OverlayPreferenceStore store) {
 		Assert.isNotNull(store);
 		fStore= store;
 		fStore.addKeys(createOverlayStoreKeys());
 		fProviderDescriptors= createListModel();
 		fProviderPreferences= new HashMap();
 		fProviderControls= new HashMap();
 	}

 	private Map createListModel() {
 		JavaFoldingStructureProviderRegistry reg= JavaPlugin.getDefault().getFoldingStructureProviderRegistry();
 		reg.reloadExtensions();
 		JavaFoldingStructureProviderDescriptor[] descs= reg.getFoldingProviderDescriptors();
 		Map map= new HashMap();
 		for (int i= 0; i < descs.length; i++) {
 			map.put(descs[i].getId(), descs[i]);
 		}
 		return map;
 	}

 	private OverlayPreferenceStore.OverlayKey[] createOverlayStoreKeys() {

 		ArrayList overlayKeys= new ArrayList();

 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, PreferenceConstants.EDITOR_FOLDING_ENABLED));
 		overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING, PreferenceConstants.EDITOR_FOLDING_PROVIDER));

 		OverlayPreferenceStore.OverlayKey[] keys= new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
 		overlayKeys.toArray(keys);
 		return keys;
 	}

 	/**
 	 * Creates page for folding preferences.
 	 *
 	 * @param parent the parent composite
 	 * @return the control for the preference page
 	 */
 	public Control createControl(Composite parent) {

 		Composite composite= new Composite(parent, SWT.NULL);
 		// assume parent page uses griddata
 		GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_CENTER | GridData.VERTICAL_ALIGN_FILL);
 		composite.setLayoutData(gd);
 		GridLayout layout= new GridLayout();
 		layout.numColumns= 2;
 		PixelConverter pc= new PixelConverter(composite);
 		layout.verticalSpacing= pc.convertHeightInCharsToPixels(1) / 2;
 		composite.setLayout(layout);


 		/* check box for new editors */
 		fFoldingCheckbox= new Button(composite, SWT.CHECK);
 		fFoldingCheckbox.setText(PreferencesMessages.FoldingConfigurationBlock_enable);
 		gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING);
 		fFoldingCheckbox.setLayoutData(gd);
 		fFoldingCheckbox.addSelectionListener(new SelectionListener() {
 			public void widgetSelected(SelectionEvent e) {
 				boolean enabled= fFoldingCheckbox.getSelection();
 				fStore.setValue(PreferenceConstants.EDITOR_FOLDING_ENABLED, enabled);
 				updateCheckboxDependencies();
 			}

 			public void widgetDefaultSelected(SelectionEvent e) {
 			}
 		});

 		Label label= new Label(composite, SWT.CENTER);
 		gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 		label.setLayoutData(gd);

 		if (fProviderDescriptors.size() > 1) {
 			/* list */
 			Composite comboComp= new Composite(composite, SWT.NONE);
 			gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 			GridLayout gridLayout= new GridLayout(2, false);
 			gridLayout.marginWidth= 0;
 			comboComp.setLayout(gridLayout);

 			Label comboLabel= new Label(comboComp, SWT.CENTER);
 			gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_CENTER);
 			comboLabel.setLayoutData(gd);
 			comboLabel.setText(PreferencesMessages.FoldingConfigurationBlock_combo_caption);

 			label= new Label(composite, SWT.CENTER);
 			gd= new GridData(GridData.FILL_HORIZONTAL | GridData.VERTICAL_ALIGN_BEGINNING);
 			label.setLayoutData(gd);

 			fProviderCombo= new Combo(comboComp, SWT.READ_ONLY | SWT.DROP_DOWN);
 			gd= new GridData(GridData.HORIZONTAL_ALIGN_END | GridData.VERTICAL_ALIGN_CENTER);
 			fProviderCombo.setLayoutData(gd);

 			fProviderViewer= createProviderViewer();
 		}

 		Composite groupComp= new Composite(composite, SWT.NONE);
 		gd= new GridData(GridData.FILL_BOTH);
 		gd.horizontalSpan= 2;
 		groupComp.setLayoutData(gd);
 		GridLayout gridLayout= new GridLayout(1, false);
 		gridLayout.marginWidth= 0;
 		groupComp.setLayout(gridLayout);

 		/* contributed provider preferences. */
 		fGroup= new Composite(groupComp, SWT.NONE);
 		gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING | GridData.VERTICAL_ALIGN_BEGINNING);
 		fGroup.setLayoutData(gd);
 		fStackLayout= new StackLayout();
 		fGroup.setLayout(fStackLayout);

 		return composite;
 	}

 	private ComboViewer createProviderViewer() {
 		/* list viewer */
 		ComboViewer viewer= new ComboViewer(fProviderCombo);
 		viewer.setContentProvider(new IStructuredContentProvider() {

 			/*
 			 * @see org.eclipse.jface.viewers.IContentProvider#dispose()
 			 */
 			public void dispose() {
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
 			 */
 			public void inputChanged(Viewer v, Object oldInput, Object newInput) {
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
 			 */
 			public Object[] getElements(Object inputElement) {
 				return fProviderDescriptors.values().toArray();
 			}
 		});
 		viewer.setLabelProvider(new LabelProvider() {
 			/*
 			 * @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
 			 */
 			public Image getImage(Object element) {
 				return null;
 			}

 			/*
 			 * @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
 			 */
 			public String getText(Object element) {
 				return ((JavaFoldingStructureProviderDescriptor) element).getName();
 			}
 		});
 		viewer.addSelectionChangedListener(new ISelectionChangedListener() {

 			public void selectionChanged(SelectionChangedEvent event) {
 				IStructuredSelection sel= (IStructuredSelection) event.getSelection();
 				if (!sel.isEmpty()) {
 					fStore.setValue(PreferenceConstants.EDITOR_FOLDING_PROVIDER, ((JavaFoldingStructureProviderDescriptor) sel.getFirstElement()).getId());
 					updateListDependencies();
 				}
 			}
 		});
 		viewer.setInput(fProviderDescriptors);
 		viewer.refresh();

 		return viewer;
 	}

 	private void updateCheckboxDependencies() {
 	}

 	void updateListDependencies() {
 		String id= fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
 		JavaFoldingStructureProviderDescriptor desc= (JavaFoldingStructureProviderDescriptor) fProviderDescriptors.get(id);
 		IJavaFoldingPreferenceBlock prefs;

 		if (desc == null) {
 			// safety in case there is no such descriptor
 			String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_error_not_exist, id);
 			JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));
 			prefs= new ErrorPreferences(message);
 		} else {
 			prefs= (IJavaFoldingPreferenceBlock) fProviderPreferences.get(id);
 			if (prefs == null) {
 				try {
 					prefs= desc.createPreferences();
 					fProviderPreferences.put(id, prefs);
 				} catch (CoreException e) {
 					JavaPlugin.log(e);
 					prefs= new ErrorPreferences(e.getLocalizedMessage());
 				}
 			}
 		}

 		Control control= (Control) fProviderControls.get(id);
 		if (control == null) {
 			control= prefs.createControl(fGroup);
 			if (control == null) {
 				String message= PreferencesMessages.FoldingConfigurationBlock_info_no_preferences;
 				control= new ErrorPreferences(message).createControl(fGroup);
 			} else {
 				fProviderControls.put(id, control);
 			}
 		}
 		Dialog.applyDialogFont(control);
 		fStackLayout.topControl= control;
 		control.pack();
 		fGroup.layout();
 		fGroup.getParent().layout();

 		prefs.initialize();
 	}

 	public void initialize() {
 		restoreFromPreferences();
 	}

 	public void performOk() {
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
 			prefs.performOk();
 		}
 	}

 	public void performDefaults() {
 		restoreFromPreferences();
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
 			prefs.performDefaults();
 		}
 	}

 	public void dispose() {
 		for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
 			IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
 			prefs.dispose();
 		}
 	}

 	private void restoreFromPreferences() {
 		boolean enabled= fStore.getBoolean(PreferenceConstants.EDITOR_FOLDING_ENABLED);
 		fFoldingCheckbox.setSelection(enabled);
 		updateCheckboxDependencies();

 		String id= fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
 		Object provider= fProviderDescriptors.get(id);

 		// Fallback to default
 		if (provider == null) {
 			String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_warning_providerNotFound_resetToDefault, id);
 			JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));

 			id= JavaPlugin.getDefault().getPreferenceStore().getDefaultString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);

 			provider= fProviderDescriptors.get(id);
 			/*
 			 * In 3.2.1 we don't want to risk anything, hence don't
 			 * Assert.isNotNull(provider);
 			 */
 			if (provider == null)
 				return;

 			fStore.setToDefault(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
 		}

 		if (fProviderViewer == null)
 			updateListDependencies();
 		else
 			fProviderViewer.setSelection(new StructuredSelection(provider), true);
 	}
 }
	/*******************************************************************************
	* Copyright (c) 2000, 2005 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
	*******************************************************************************/

	package org.eclipse.jdt.internal.ui.preferences;

	import java.util.ArrayList;
	import java.util.HashMap;
	import java.util.Iterator;
	import java.util.Map;

	import org.eclipse.core.runtime.CoreException;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.core.runtime.Status;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.custom.StackLayout;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.layout.FillLayout;
	import org.eclipse.swt.layout.GridData;
	import org.eclipse.swt.layout.GridLayout;
	import org.eclipse.swt.widgets.Button;
	import org.eclipse.swt.widgets.Combo;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Control;
	import org.eclipse.swt.widgets.Label;

	import org.eclipse.jface.dialogs.Dialog;
	import org.eclipse.jface.viewers.ComboViewer;
	import org.eclipse.jface.viewers.ISelectionChangedListener;
	import org.eclipse.jface.viewers.IStructuredContentProvider;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.LabelProvider;
	import org.eclipse.jface.viewers.SelectionChangedEvent;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.jface.viewers.Viewer;

	import org.eclipse.jface.text.Assert;

	import org.eclipse.jdt.internal.corext.util.Messages;

	import org.eclipse.jdt.ui.PreferenceConstants;
	import org.eclipse.jdt.ui.text.folding.IJavaFoldingPreferenceBlock;

	import org.eclipse.jdt.internal.ui.JavaPlugin;
	import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderDescriptor;
	import org.eclipse.jdt.internal.ui.text.folding.JavaFoldingStructureProviderRegistry;
	import org.eclipse.jdt.internal.ui.util.PixelConverter;

	/**
	* Configures Java Editor folding preferences.
	*
	* @since 3.0
	*/
	class FoldingConfigurationBlock implements IPreferenceConfigurationBlock {

	private static class ErrorPreferences implements IJavaFoldingPreferenceBlock {
	private String fMessage;

	protected ErrorPreferences(String message) {
	fMessage= message;
	}

	/*
	* @see org.eclipse.jdt.internal.ui.text.folding.IJavaFoldingPreferences#createControl(org.eclipse.swt.widgets.Group)
	*/
	public Control createControl(Composite composite) {
	Composite inner= new Composite(composite, SWT.NONE);
	inner.setLayout(new FillLayout(SWT.VERTICAL));

	Label label= new Label(inner, SWT.CENTER);
	label.setText(fMessage);

	return inner;
	}

	public void initialize() {
	}

	public void performOk() {
	}

	public void performDefaults() {
	}

	public void dispose() {
	}

	}

	/** The overlay preference store. */
	private final OverlayPreferenceStore fStore;

	/* The controls */
	private Combo fProviderCombo;
	private Button fFoldingCheckbox;
	private ComboViewer fProviderViewer;
	private Composite fGroup;
	private StackLayout fStackLayout;

	/* the model */
	private final Map fProviderDescriptors;
	private final Map fProviderPreferences;
	private final Map fProviderControls;


	public FoldingConfigurationBlock(OverlayPreferenceStore store) {
	Assert.isNotNull(store);
	fStore= store;
	fStore.addKeys(createOverlayStoreKeys());
	fProviderDescriptors= createListModel();
	fProviderPreferences= new HashMap();
	fProviderControls= new HashMap();
	}

	private Map createListModel() {
	JavaFoldingStructureProviderRegistry reg= JavaPlugin.getDefault().getFoldingStructureProviderRegistry();
	reg.reloadExtensions();
	JavaFoldingStructureProviderDescriptor[] descs= reg.getFoldingProviderDescriptors();
	Map map= new HashMap();
	for (int i= 0; i < descs.length; i++) {
	map.put(descs[i].getId(), descs[i]);
	}
	return map;
	}

	private OverlayPreferenceStore.OverlayKey[] createOverlayStoreKeys() {

	ArrayList overlayKeys= new ArrayList();

	overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.BOOLEAN, PreferenceConstants.EDITOR_FOLDING_ENABLED));
	overlayKeys.add(new OverlayPreferenceStore.OverlayKey(OverlayPreferenceStore.STRING, PreferenceConstants.EDITOR_FOLDING_PROVIDER));

	OverlayPreferenceStore.OverlayKey[] keys= new OverlayPreferenceStore.OverlayKey[overlayKeys.size()];
	overlayKeys.toArray(keys);
	return keys;
	}

	/**
	* Creates page for folding preferences.
	*
	* @param parent the parent composite
	* @return the control for the preference page
	*/
	public Control createControl(Composite parent) {

	Composite composite= new Composite(parent, SWT.NULL);
	// assume parent page uses griddata
	GridData gd= new GridData(GridData.HORIZONTAL_ALIGN_CENTER \| GridData.VERTICAL_ALIGN_FILL);
	composite.setLayoutData(gd);
	GridLayout layout= new GridLayout();
	layout.numColumns= 2;
	PixelConverter pc= new PixelConverter(composite);
	layout.verticalSpacing= pc.convertHeightInCharsToPixels(1) / 2;
	composite.setLayout(layout);


	/* check box for new editors */
	fFoldingCheckbox= new Button(composite, SWT.CHECK);
	fFoldingCheckbox.setText(PreferencesMessages.FoldingConfigurationBlock_enable);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING \| GridData.VERTICAL_ALIGN_BEGINNING);
	fFoldingCheckbox.setLayoutData(gd);
	fFoldingCheckbox.addSelectionListener(new SelectionListener() {
	public void widgetSelected(SelectionEvent e) {
	boolean enabled= fFoldingCheckbox.getSelection();
	fStore.setValue(PreferenceConstants.EDITOR_FOLDING_ENABLED, enabled);
	updateCheckboxDependencies();
	}

	public void widgetDefaultSelected(SelectionEvent e) {
	}
	});

	Label label= new Label(composite, SWT.CENTER);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	label.setLayoutData(gd);

	if (fProviderDescriptors.size() > 1) {
	/* list */
	Composite comboComp= new Composite(composite, SWT.NONE);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	GridLayout gridLayout= new GridLayout(2, false);
	gridLayout.marginWidth= 0;
	comboComp.setLayout(gridLayout);

	Label comboLabel= new Label(comboComp, SWT.CENTER);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING \| GridData.VERTICAL_ALIGN_CENTER);
	comboLabel.setLayoutData(gd);
	comboLabel.setText(PreferencesMessages.FoldingConfigurationBlock_combo_caption);

	label= new Label(composite, SWT.CENTER);
	gd= new GridData(GridData.FILL_HORIZONTAL \| GridData.VERTICAL_ALIGN_BEGINNING);
	label.setLayoutData(gd);

	fProviderCombo= new Combo(comboComp, SWT.READ_ONLY \| SWT.DROP_DOWN);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_END \| GridData.VERTICAL_ALIGN_CENTER);
	fProviderCombo.setLayoutData(gd);

	fProviderViewer= createProviderViewer();
	}

	Composite groupComp= new Composite(composite, SWT.NONE);
	gd= new GridData(GridData.FILL_BOTH);
	gd.horizontalSpan= 2;
	groupComp.setLayoutData(gd);
	GridLayout gridLayout= new GridLayout(1, false);
	gridLayout.marginWidth= 0;
	groupComp.setLayout(gridLayout);

	/* contributed provider preferences. */
	fGroup= new Composite(groupComp, SWT.NONE);
	gd= new GridData(GridData.HORIZONTAL_ALIGN_BEGINNING \| GridData.VERTICAL_ALIGN_BEGINNING);
	fGroup.setLayoutData(gd);
	fStackLayout= new StackLayout();
	fGroup.setLayout(fStackLayout);

	return composite;
	}

	private ComboViewer createProviderViewer() {
	/* list viewer */
	ComboViewer viewer= new ComboViewer(fProviderCombo);
	viewer.setContentProvider(new IStructuredContentProvider() {

	/*
	* @see org.eclipse.jface.viewers.IContentProvider#dispose()
	*/
	public void dispose() {
	}

	/*
	* @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object)
	*/
	public void inputChanged(Viewer v, Object oldInput, Object newInput) {
	}

	/*
	* @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object)
	*/
	public Object[] getElements(Object inputElement) {
	return fProviderDescriptors.values().toArray();
	}
	});
	viewer.setLabelProvider(new LabelProvider() {
	/*
	* @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
	*/
	public Image getImage(Object element) {
	return null;
	}

	/*
	* @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
	*/
	public String getText(Object element) {
	return ((JavaFoldingStructureProviderDescriptor) element).getName();
	}
	});
	viewer.addSelectionChangedListener(new ISelectionChangedListener() {

	public void selectionChanged(SelectionChangedEvent event) {
	IStructuredSelection sel= (IStructuredSelection) event.getSelection();
	if (!sel.isEmpty()) {
	fStore.setValue(PreferenceConstants.EDITOR_FOLDING_PROVIDER, ((JavaFoldingStructureProviderDescriptor) sel.getFirstElement()).getId());
	updateListDependencies();
	}
	}
	});
	viewer.setInput(fProviderDescriptors);
	viewer.refresh();

	return viewer;
	}

	private void updateCheckboxDependencies() {
	}

	void updateListDependencies() {
	String id= fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
	JavaFoldingStructureProviderDescriptor desc= (JavaFoldingStructureProviderDescriptor) fProviderDescriptors.get(id);
	IJavaFoldingPreferenceBlock prefs;

	if (desc == null) {
	// safety in case there is no such descriptor
	String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_error_not_exist, id);
	JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));
	prefs= new ErrorPreferences(message);
	} else {
	prefs= (IJavaFoldingPreferenceBlock) fProviderPreferences.get(id);
	if (prefs == null) {
	try {
	prefs= desc.createPreferences();
	fProviderPreferences.put(id, prefs);
	} catch (CoreException e) {
	JavaPlugin.log(e);
	prefs= new ErrorPreferences(e.getLocalizedMessage());
	}
	}
	}

	Control control= (Control) fProviderControls.get(id);
	if (control == null) {
	control= prefs.createControl(fGroup);
	if (control == null) {
	String message= PreferencesMessages.FoldingConfigurationBlock_info_no_preferences;
	control= new ErrorPreferences(message).createControl(fGroup);
	} else {
	fProviderControls.put(id, control);
	}
	}
	Dialog.applyDialogFont(control);
	fStackLayout.topControl= control;
	control.pack();
	fGroup.layout();
	fGroup.getParent().layout();

	prefs.initialize();
	}

	public void initialize() {
	restoreFromPreferences();
	}

	public void performOk() {
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
	prefs.performOk();
	}
	}

	public void performDefaults() {
	restoreFromPreferences();
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
	prefs.performDefaults();
	}
	}

	public void dispose() {
	for (Iterator it= fProviderPreferences.values().iterator(); it.hasNext();) {
	IJavaFoldingPreferenceBlock prefs= (IJavaFoldingPreferenceBlock) it.next();
	prefs.dispose();
	}
	}

	private void restoreFromPreferences() {
	boolean enabled= fStore.getBoolean(PreferenceConstants.EDITOR_FOLDING_ENABLED);
	fFoldingCheckbox.setSelection(enabled);
	updateCheckboxDependencies();

	String id= fStore.getString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
	Object provider= fProviderDescriptors.get(id);

	// Fallback to default
	if (provider == null) {
	String message= Messages.format(PreferencesMessages.FoldingConfigurationBlock_warning_providerNotFound_resetToDefault, id);
	JavaPlugin.log(new Status(IStatus.WARNING, JavaPlugin.getPluginId(), IStatus.OK, message, null));

	id= JavaPlugin.getDefault().getPreferenceStore().getDefaultString(PreferenceConstants.EDITOR_FOLDING_PROVIDER);

	provider= fProviderDescriptors.get(id);
	/*
	* In 3.2.1 we don't want to risk anything, hence don't
	* Assert.isNotNull(provider);
	*/
	if (provider == null)
	return;

	fStore.setToDefault(PreferenceConstants.EDITOR_FOLDING_PROVIDER);
	}

	if (fProviderViewer == null)
	updateListDependencies();
	else
	fProviderViewer.setSelection(new StructuredSelection(provider), true);
	}
	}