bundles/org.eclipse.e4.tools.emf.ui/src/org/eclipse/e4/tools/emf/ui/internal/common/component/dialogs/FindParentReferenceElementDialog.java - platform/eclipse.platform.ui.tools - Git at Google

 /*******************************************************************************
  * Copyright (c) 2010, 2017 BestSolution.at 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:
  * Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
  * Steven Spungin <steven@spungin.tv> - Bug 437469
  * Patrik Suzzi <psuzzi@gmail.com> - Bug 467262
  * Olivier Prouvost <olivier.prouvost@opcoach.com> - Bug 509488, 509551
  ******************************************************************************/
 package org.eclipse.e4.tools.emf.ui.internal.common.component.dialogs;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;

 import org.eclipse.core.databinding.observable.list.WritableList;
 import org.eclipse.e4.tools.emf.ui.common.IModelElementProvider.Filter;
 import org.eclipse.e4.tools.emf.ui.common.Util;
 import org.eclipse.e4.tools.emf.ui.common.Util.InternalPackage;
 import org.eclipse.e4.tools.emf.ui.common.component.AbstractComponentEditor;
 import org.eclipse.e4.tools.emf.ui.internal.Messages;
 import org.eclipse.e4.tools.emf.ui.internal.common.ClassContributionCollector;
 import org.eclipse.e4.ui.model.application.MApplicationElement;
 import org.eclipse.e4.ui.model.application.impl.ApplicationPackageImpl;
 import org.eclipse.e4.ui.model.fragment.MStringModelFragment;
 import org.eclipse.e4.ui.model.fragment.impl.FragmentPackageImpl;
 import org.eclipse.emf.common.command.Command;
 import org.eclipse.emf.ecore.EClass;
 import org.eclipse.emf.ecore.EObject;
 import org.eclipse.emf.edit.command.SetCommand;
 import org.eclipse.jface.databinding.viewers.ObservableListContentProvider;
 import org.eclipse.jface.dialogs.TitleAreaDialog;
 import org.eclipse.jface.fieldassist.AutoCompleteField;
 import org.eclipse.jface.fieldassist.ComboContentAdapter;
 import org.eclipse.jface.viewers.ArrayContentProvider;
 import org.eclipse.jface.viewers.ComboViewer;
 import org.eclipse.jface.viewers.IStructuredSelection;
 import org.eclipse.jface.viewers.LabelProvider;
 import org.eclipse.jface.viewers.StructuredSelection;
 import org.eclipse.jface.viewers.StyledCellLabelProvider;
 import org.eclipse.jface.viewers.StyledString;
 import org.eclipse.jface.viewers.TableViewer;
 import org.eclipse.jface.viewers.Viewer;
 import org.eclipse.jface.viewers.ViewerCell;
 import org.eclipse.jface.viewers.ViewerComparator;
 import org.eclipse.swt.SWT;
 import org.eclipse.swt.events.SelectionAdapter;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.graphics.Image;
 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.swt.widgets.Shell;
 import org.eclipse.swt.widgets.Text;
 import org.osgi.framework.Bundle;
 import org.osgi.framework.BundleContext;
 import org.osgi.framework.FrameworkUtil;
 import org.osgi.framework.ServiceReference;

 public class FindParentReferenceElementDialog extends TitleAreaDialog {
 	private final MStringModelFragment fragment;
 	private final AbstractComponentEditor editor;
 	private TableViewer viewer;
 	private final Messages Messages;
 	private ModelResultHandlerImpl currentResultHandler;
 	private WritableList list;
 	private ComboViewer eClassViewer;
 	private Text searchText;
 	private EClass selectedContainer;
 	private ClassContributionCollector collector;

 	/** Remember of classes that can be used for a fragment definition. */
 	private static List<EClass> extendableClasses = null;

 	public FindParentReferenceElementDialog(Shell parentShell, AbstractComponentEditor editor,
 			MStringModelFragment fragment, Messages Messages, EClass previousSelection) {
 		super(parentShell);
 		this.fragment = fragment;
 		this.editor = editor;
 		this.Messages = Messages;
 		this.collector = getCollector();
 		this.selectedContainer = previousSelection;
 	}

 	private ClassContributionCollector getCollector() {
 		final Bundle bundle = FrameworkUtil.getBundle(FindParentReferenceElementDialog.class);
 		final BundleContext context = bundle.getBundleContext();
 		final ServiceReference<?> ref = context.getServiceReference(ClassContributionCollector.class.getName());
 		if (ref != null) {
 			return (ClassContributionCollector) context.getService(ref);
 		}
 		return null;
 	}

 	@Override
 	protected boolean isResizable() {
 		return true;
 	}

 	@Override
 	protected Control createDialogArea(Composite parent) {
 		final Composite comp = (Composite) super.createDialogArea(parent);

 		final Image titleImage = new Image(parent.getDisplay(),
 				getClass().getClassLoader().getResourceAsStream("/icons/full/wizban/import_wiz.png")); //$NON-NLS-1$
 		setTitleImage(titleImage);
 		getShell().addDisposeListener(e -> titleImage.dispose());

 		getShell().setText(Messages.FindParentReferenceElementDialog_ShellTitle);
 		setTitle(Messages.FindParentReferenceElementDialog_Title);
 		setMessage(Messages.FindParentReferenceElementDialog_Message);

 		final Composite container = new Composite(comp, SWT.NONE);
 		container.setLayoutData(new GridData(GridData.FILL_BOTH));
 		container.setLayout(new GridLayout(2, false));

 		Label l = new Label(container, SWT.NONE);
 		l.setText(Messages.FindParentReferenceElementDialog_ContainerType);

 		Composite parentForCombo = new Composite(container, SWT.NONE);
 		parentForCombo.setLayout(new GridLayout(2, false));
 		parentForCombo.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true, false));

 		final Combo combo = new Combo(parentForCombo, SWT.NONE);
 		eClassViewer = new ComboViewer(combo);
 		combo.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true, false));
 		eClassViewer.setLabelProvider(new LabelProvider() {
 			@Override
 			public String getText(Object element) {
 				return ((EClass) element).getName();
 			}
 		});
 		eClassViewer.setContentProvider(new ArrayContentProvider());
 		final List<EClass> eClassList = getExtendableClasses();
 		eClassViewer.setComparator(new ViewerComparator() {
 			@Override
 			public int compare(Viewer viewer, Object e1, Object e2) {
 				final EClass ec1 = (EClass) e1;
 				final EClass ec2 = (EClass) e2;
 				return ec1.getName().compareTo(ec2.getName());
 			}
 		});
 		eClassViewer.setInput(eClassList);
 		eClassViewer.getControl().setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
 		eClassViewer.addSelectionChangedListener(event -> updateSearch());

 		final ArrayList<String> vals = new ArrayList<>();
 		for (final EClass item : eClassList) {
 			vals.add(item.getName());
 		}
 		final String[] values = vals.toArray(new String[0]);
 		final ComboContentAdapter textContentAdapter = new ComboContentAdapter() {
 			@Override
 			public void setControlContents(Control control, String text1, int cursorPosition) {
 				super.setControlContents(control, text1, cursorPosition);
 				final int index = Arrays.asList(values).indexOf(text1);
 				final EClass eClass = eClassList.get(index);
 				eClassViewer.setSelection(new StructuredSelection(eClass));
 			}
 		};
 		new AutoCompleteField(combo, textContentAdapter, values);

 		Label help = new Label(parentForCombo, SWT.NONE);
 		final Image helpImage = new Image(parent.getDisplay(),
 				getClass().getClassLoader().getResourceAsStream("/icons/full/obj16/missing_image_placeholder.png")); //$NON-NLS-1$
 		help.setImage(helpImage);
 		help.setToolTipText(Messages.FindParentReferenceElementDialog_HelpTooltip);

 		l = new Label(container, SWT.NONE);
 		l.setText(Messages.FindParentReferenceElementDialog_Search);

 		searchText = new Text(container, SWT.BORDER | SWT.SEARCH | SWT.ICON_SEARCH);
 		GridData gd = new GridData(GridData.FILL_HORIZONTAL);
 		searchText.setLayoutData(gd);

 		l = new Label(container, SWT.PUSH);

 		viewer = new TableViewer(container);
 		gd = new GridData(GridData.FILL_BOTH);
 		gd.heightHint = 200;
 		viewer.getControl().setLayoutData(gd);
 		viewer.setLabelProvider(new StyledCellLabelProvider() {
 			@Override
 			public void update(ViewerCell cell) {
 				final EObject o = (EObject) cell.getElement();
 				final AbstractComponentEditor editor = FindParentReferenceElementDialog.this.editor.getEditor()
 						.getEditor(o.eClass());
 				cell.setImage(editor.getImage(o));

 				final MApplicationElement appEl = (MApplicationElement) o;

 				final StyledString styledString = new StyledString(editor.getLabel(o) + " (" //$NON-NLS-1$
 						+ (appEl.getElementId() == null
 						? "<" + Messages.FindParentReferenceElementDialog_NoId + ">" : appEl.getElementId()) //$NON-NLS-1$ //$NON-NLS-2$
 						+ ")", null); //$NON-NLS-1$
 				final String detailLabel = editor.getDetailLabel(o);
 				if (detailLabel != null && !detailLabel.equals(appEl.getElementId())) {
 					styledString.append(" - " + detailLabel, StyledString.DECORATIONS_STYLER); //$NON-NLS-1$
 				}

 				styledString.append(" - " + o.eResource().getURI(), StyledString.COUNTER_STYLER); //$NON-NLS-1$
 				cell.setStyleRanges(styledString.getStyleRanges());
 				cell.setText(styledString.getString());
 			}
 		});
 		viewer.setContentProvider(new ObservableListContentProvider());
 		viewer.addDoubleClickListener(event -> okPressed());

 		list = new WritableList();
 		viewer.setInput(list);

 		searchText.addModifyListener(e -> updateSearch());

 		final Button button = new Button(container, SWT.PUSH);
 		button.setText(Messages.FindParentReferenceElementDialog_ClearCache);
 		button.setLayoutData(new GridData(GridData.END, GridData.CENTER, true, false, 2, 1));
 		button.addSelectionListener(new SelectionAdapter() {
 			@Override
 			public void widgetSelected(SelectionEvent e) {
 				collector.clearModelCache();
 			}
 		});

 		// Manage the current selection on comboviewer (previous or first one).
 		if (selectedContainer != null) {
 			eClassViewer.setSelection(new StructuredSelection(selectedContainer));
 		} else {
 			// Select addon by default (not necessary in the first position in
 			// the eclasslist...)
 			eClassViewer.setSelection(new StructuredSelection(ApplicationPackageImpl.Literals.APPLICATION));
 		}

 		return comp;
 	}

 	/**
 	 * This method returns classes that have extensible fields It rejects
 	 * eClasses having only transientData and persistedState for instance Result
 	 * is cached in a singleton for each dialog instances...
 	 *
 	 * @return
 	 */
 	private List<EClass> getExtendableClasses() {
 		if (extendableClasses == null) {
 			extendableClasses = new ArrayList<>();
 			for (final InternalPackage p : Util.loadPackages()) {
 				for (EClass c : p.getAllClasses()) {
 					if (Util.canBeExtendedInAFragment(c)) {
 						extendableClasses.add(c);
 					}
 				}
 			}
 		}
 		return extendableClasses;
 	}


 	protected void updateSearch() {
 		if (currentResultHandler != null) {
 			currentResultHandler.cancel();
 		}
 		list.clear();

 		final Filter filter = new Filter(
 				(EClass) ((IStructuredSelection) eClassViewer.getSelection()).getFirstElement(), searchText.getText());

 		currentResultHandler = new ModelResultHandlerImpl(list, filter, editor, ((EObject) fragment).eResource());
 		collector.findModelElements(filter, currentResultHandler);

 	}

 	@Override
 	protected void okPressed() {
 		final IStructuredSelection s = (IStructuredSelection) viewer.getSelection();
 		if (!s.isEmpty()) {
 			final MApplicationElement el = (MApplicationElement) s.getFirstElement();
 			if (el.getElementId() != null && el.getElementId().trim().length() > 0) {
 				final Command cmd = SetCommand.create(editor.getEditingDomain(), fragment,
 						FragmentPackageImpl.Literals.STRING_MODEL_FRAGMENT__PARENT_ELEMENT_ID, el.getElementId());
 				if (cmd.canExecute()) {
 					selectedContainer = (EClass) ((IStructuredSelection) eClassViewer.getSelection()).getFirstElement();
 					editor.getEditingDomain().getCommandStack().execute(cmd);
 					super.okPressed();
 				}
 			} else {
 				setErrorMessage(Messages.FindParentReferenceElementDialog_NoReferenceId);
 			}
 		}
 	}

 	/**
 	 * Gets the selected EClass container after a successeful selection of the
 	 * parent
 	 *
 	 * @return the selectedContainer
 	 */
 	public EClass getSelectedContainer() {
 		return selectedContainer;
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2010, 2017 BestSolution.at 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:
	* Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
	* Steven Spungin <steven@spungin.tv> - Bug 437469
	* Patrik Suzzi <psuzzi@gmail.com> - Bug 467262
	* Olivier Prouvost <olivier.prouvost@opcoach.com> - Bug 509488, 509551
	******************************************************************************/
	package org.eclipse.e4.tools.emf.ui.internal.common.component.dialogs;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.List;

	import org.eclipse.core.databinding.observable.list.WritableList;
	import org.eclipse.e4.tools.emf.ui.common.IModelElementProvider.Filter;
	import org.eclipse.e4.tools.emf.ui.common.Util;
	import org.eclipse.e4.tools.emf.ui.common.Util.InternalPackage;
	import org.eclipse.e4.tools.emf.ui.common.component.AbstractComponentEditor;
	import org.eclipse.e4.tools.emf.ui.internal.Messages;
	import org.eclipse.e4.tools.emf.ui.internal.common.ClassContributionCollector;
	import org.eclipse.e4.ui.model.application.MApplicationElement;
	import org.eclipse.e4.ui.model.application.impl.ApplicationPackageImpl;
	import org.eclipse.e4.ui.model.fragment.MStringModelFragment;
	import org.eclipse.e4.ui.model.fragment.impl.FragmentPackageImpl;
	import org.eclipse.emf.common.command.Command;
	import org.eclipse.emf.ecore.EClass;
	import org.eclipse.emf.ecore.EObject;
	import org.eclipse.emf.edit.command.SetCommand;
	import org.eclipse.jface.databinding.viewers.ObservableListContentProvider;
	import org.eclipse.jface.dialogs.TitleAreaDialog;
	import org.eclipse.jface.fieldassist.AutoCompleteField;
	import org.eclipse.jface.fieldassist.ComboContentAdapter;
	import org.eclipse.jface.viewers.ArrayContentProvider;
	import org.eclipse.jface.viewers.ComboViewer;
	import org.eclipse.jface.viewers.IStructuredSelection;
	import org.eclipse.jface.viewers.LabelProvider;
	import org.eclipse.jface.viewers.StructuredSelection;
	import org.eclipse.jface.viewers.StyledCellLabelProvider;
	import org.eclipse.jface.viewers.StyledString;
	import org.eclipse.jface.viewers.TableViewer;
	import org.eclipse.jface.viewers.Viewer;
	import org.eclipse.jface.viewers.ViewerCell;
	import org.eclipse.jface.viewers.ViewerComparator;
	import org.eclipse.swt.SWT;
	import org.eclipse.swt.events.SelectionAdapter;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.graphics.Image;
	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.swt.widgets.Shell;
	import org.eclipse.swt.widgets.Text;
	import org.osgi.framework.Bundle;
	import org.osgi.framework.BundleContext;
	import org.osgi.framework.FrameworkUtil;
	import org.osgi.framework.ServiceReference;

	public class FindParentReferenceElementDialog extends TitleAreaDialog {
	private final MStringModelFragment fragment;
	private final AbstractComponentEditor editor;
	private TableViewer viewer;
	private final Messages Messages;
	private ModelResultHandlerImpl currentResultHandler;
	private WritableList list;
	private ComboViewer eClassViewer;
	private Text searchText;
	private EClass selectedContainer;
	private ClassContributionCollector collector;

	/** Remember of classes that can be used for a fragment definition. */
	private static List<EClass> extendableClasses = null;

	public FindParentReferenceElementDialog(Shell parentShell, AbstractComponentEditor editor,
	MStringModelFragment fragment, Messages Messages, EClass previousSelection) {
	super(parentShell);
	this.fragment = fragment;
	this.editor = editor;
	this.Messages = Messages;
	this.collector = getCollector();
	this.selectedContainer = previousSelection;
	}

	private ClassContributionCollector getCollector() {
	final Bundle bundle = FrameworkUtil.getBundle(FindParentReferenceElementDialog.class);
	final BundleContext context = bundle.getBundleContext();
	final ServiceReference<?> ref = context.getServiceReference(ClassContributionCollector.class.getName());
	if (ref != null) {
	return (ClassContributionCollector) context.getService(ref);
	}
	return null;
	}

	@Override
	protected boolean isResizable() {
	return true;
	}

	@Override
	protected Control createDialogArea(Composite parent) {
	final Composite comp = (Composite) super.createDialogArea(parent);

	final Image titleImage = new Image(parent.getDisplay(),
	getClass().getClassLoader().getResourceAsStream("/icons/full/wizban/import_wiz.png")); //$NON-NLS-1$
	setTitleImage(titleImage);
	getShell().addDisposeListener(e -> titleImage.dispose());

	getShell().setText(Messages.FindParentReferenceElementDialog_ShellTitle);
	setTitle(Messages.FindParentReferenceElementDialog_Title);
	setMessage(Messages.FindParentReferenceElementDialog_Message);

	final Composite container = new Composite(comp, SWT.NONE);
	container.setLayoutData(new GridData(GridData.FILL_BOTH));
	container.setLayout(new GridLayout(2, false));

	Label l = new Label(container, SWT.NONE);
	l.setText(Messages.FindParentReferenceElementDialog_ContainerType);

	Composite parentForCombo = new Composite(container, SWT.NONE);
	parentForCombo.setLayout(new GridLayout(2, false));
	parentForCombo.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true, false));

	final Combo combo = new Combo(parentForCombo, SWT.NONE);
	eClassViewer = new ComboViewer(combo);
	combo.setLayoutData(new GridData(SWT.FILL, SWT.TOP, true, false));
	eClassViewer.setLabelProvider(new LabelProvider() {
	@Override
	public String getText(Object element) {
	return ((EClass) element).getName();
	}
	});
	eClassViewer.setContentProvider(new ArrayContentProvider());
	final List<EClass> eClassList = getExtendableClasses();
	eClassViewer.setComparator(new ViewerComparator() {
	@Override
	public int compare(Viewer viewer, Object e1, Object e2) {
	final EClass ec1 = (EClass) e1;
	final EClass ec2 = (EClass) e2;
	return ec1.getName().compareTo(ec2.getName());
	}
	});
	eClassViewer.setInput(eClassList);
	eClassViewer.getControl().setLayoutData(new GridData(GridData.FILL_HORIZONTAL));
	eClassViewer.addSelectionChangedListener(event -> updateSearch());

	final ArrayList<String> vals = new ArrayList<>();
	for (final EClass item : eClassList) {
	vals.add(item.getName());
	}
	final String[] values = vals.toArray(new String[0]);
	final ComboContentAdapter textContentAdapter = new ComboContentAdapter() {
	@Override
	public void setControlContents(Control control, String text1, int cursorPosition) {
	super.setControlContents(control, text1, cursorPosition);
	final int index = Arrays.asList(values).indexOf(text1);
	final EClass eClass = eClassList.get(index);
	eClassViewer.setSelection(new StructuredSelection(eClass));
	}
	};
	new AutoCompleteField(combo, textContentAdapter, values);

	Label help = new Label(parentForCombo, SWT.NONE);
	final Image helpImage = new Image(parent.getDisplay(),
	getClass().getClassLoader().getResourceAsStream("/icons/full/obj16/missing_image_placeholder.png")); //$NON-NLS-1$
	help.setImage(helpImage);
	help.setToolTipText(Messages.FindParentReferenceElementDialog_HelpTooltip);

	l = new Label(container, SWT.NONE);
	l.setText(Messages.FindParentReferenceElementDialog_Search);

	searchText = new Text(container, SWT.BORDER \| SWT.SEARCH \| SWT.ICON_SEARCH);
	GridData gd = new GridData(GridData.FILL_HORIZONTAL);
	searchText.setLayoutData(gd);

	l = new Label(container, SWT.PUSH);

	viewer = new TableViewer(container);
	gd = new GridData(GridData.FILL_BOTH);
	gd.heightHint = 200;
	viewer.getControl().setLayoutData(gd);
	viewer.setLabelProvider(new StyledCellLabelProvider() {
	@Override
	public void update(ViewerCell cell) {
	final EObject o = (EObject) cell.getElement();
	final AbstractComponentEditor editor = FindParentReferenceElementDialog.this.editor.getEditor()
	.getEditor(o.eClass());
	cell.setImage(editor.getImage(o));

	final MApplicationElement appEl = (MApplicationElement) o;

	final StyledString styledString = new StyledString(editor.getLabel(o) + " (" //$NON-NLS-1$
	+ (appEl.getElementId() == null
	? "<" + Messages.FindParentReferenceElementDialog_NoId + ">" : appEl.getElementId()) //$NON-NLS-1$ //$NON-NLS-2$
	+ ")", null); //$NON-NLS-1$
	final String detailLabel = editor.getDetailLabel(o);
	if (detailLabel != null && !detailLabel.equals(appEl.getElementId())) {
	styledString.append(" - " + detailLabel, StyledString.DECORATIONS_STYLER); //$NON-NLS-1$
	}

	styledString.append(" - " + o.eResource().getURI(), StyledString.COUNTER_STYLER); //$NON-NLS-1$
	cell.setStyleRanges(styledString.getStyleRanges());
	cell.setText(styledString.getString());
	}
	});
	viewer.setContentProvider(new ObservableListContentProvider());
	viewer.addDoubleClickListener(event -> okPressed());

	list = new WritableList();
	viewer.setInput(list);

	searchText.addModifyListener(e -> updateSearch());

	final Button button = new Button(container, SWT.PUSH);
	button.setText(Messages.FindParentReferenceElementDialog_ClearCache);
	button.setLayoutData(new GridData(GridData.END, GridData.CENTER, true, false, 2, 1));
	button.addSelectionListener(new SelectionAdapter() {
	@Override
	public void widgetSelected(SelectionEvent e) {
	collector.clearModelCache();
	}
	});

	// Manage the current selection on comboviewer (previous or first one).
	if (selectedContainer != null) {
	eClassViewer.setSelection(new StructuredSelection(selectedContainer));
	} else {
	// Select addon by default (not necessary in the first position in
	// the eclasslist...)
	eClassViewer.setSelection(new StructuredSelection(ApplicationPackageImpl.Literals.APPLICATION));
	}

	return comp;
	}

	/**
	* This method returns classes that have extensible fields It rejects
	* eClasses having only transientData and persistedState for instance Result
	* is cached in a singleton for each dialog instances...
	*
	* @return
	*/
	private List<EClass> getExtendableClasses() {
	if (extendableClasses == null) {
	extendableClasses = new ArrayList<>();
	for (final InternalPackage p : Util.loadPackages()) {
	for (EClass c : p.getAllClasses()) {
	if (Util.canBeExtendedInAFragment(c)) {
	extendableClasses.add(c);
	}
	}
	}
	}
	return extendableClasses;
	}



	protected void updateSearch() {
	if (currentResultHandler != null) {
	currentResultHandler.cancel();
	}
	list.clear();

	final Filter filter = new Filter(
	(EClass) ((IStructuredSelection) eClassViewer.getSelection()).getFirstElement(), searchText.getText());

	currentResultHandler = new ModelResultHandlerImpl(list, filter, editor, ((EObject) fragment).eResource());
	collector.findModelElements(filter, currentResultHandler);

	}

	@Override
	protected void okPressed() {
	final IStructuredSelection s = (IStructuredSelection) viewer.getSelection();
	if (!s.isEmpty()) {
	final MApplicationElement el = (MApplicationElement) s.getFirstElement();
	if (el.getElementId() != null && el.getElementId().trim().length() > 0) {
	final Command cmd = SetCommand.create(editor.getEditingDomain(), fragment,
	FragmentPackageImpl.Literals.STRING_MODEL_FRAGMENT__PARENT_ELEMENT_ID, el.getElementId());
	if (cmd.canExecute()) {
	selectedContainer = (EClass) ((IStructuredSelection) eClassViewer.getSelection()).getFirstElement();
	editor.getEditingDomain().getCommandStack().execute(cmd);
	super.okPressed();
	}
	} else {
	setErrorMessage(Messages.FindParentReferenceElementDialog_NoReferenceId);
	}
	}
	}

	/**
	* Gets the selected EClass container after a successeful selection of the
	* parent
	*
	* @return the selectedContainer
	*/
	public EClass getSelectedContainer() {
	return selectedContainer;
	}

	}