org.eclipse.gmf.runtime.diagram.ui/src/org/eclipse/gmf/runtime/diagram/ui/commands/PromptForConnectionAndEndCommand.java - gmf-runtime/org.eclipse.gmf-runtime - Git at Google

 /******************************************************************************
  * Copyright (c) 2005, 2006 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.gmf.runtime.diagram.ui.commands;

 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;

 import org.eclipse.core.commands.ExecutionException;
 import org.eclipse.core.runtime.IAdaptable;
 import org.eclipse.core.runtime.IProgressMonitor;
 import org.eclipse.gef.EditPart;
 import org.eclipse.gef.Request;
 import org.eclipse.gef.commands.Command;
 import org.eclipse.gef.requests.CreateConnectionRequest;
 import org.eclipse.gmf.runtime.common.core.command.CommandResult;
 import org.eclipse.gmf.runtime.common.core.util.ObjectAdapter;
 import org.eclipse.gmf.runtime.diagram.ui.editparts.IGraphicalEditPart;
 import org.eclipse.gmf.runtime.diagram.ui.internal.commands.ElementTypeLabelProvider;
 import org.eclipse.gmf.runtime.diagram.ui.l10n.DiagramUIMessages;
 import org.eclipse.gmf.runtime.diagram.ui.menus.PopupMenu;
 import org.eclipse.gmf.runtime.diagram.ui.requests.CreateConnectionViewAndElementRequest;
 import org.eclipse.gmf.runtime.diagram.ui.requests.CreateConnectionViewRequest;
 import org.eclipse.gmf.runtime.diagram.ui.requests.CreateUnspecifiedTypeConnectionRequest;
 import org.eclipse.gmf.runtime.diagram.ui.requests.CreateViewRequestFactory;
 import org.eclipse.gmf.runtime.emf.type.core.IElementType;
 import org.eclipse.gmf.runtime.emf.type.core.requests.CreateRelationshipRequest;
 import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.ModelingAssistantService;
 import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.SelectExistingElementForSourceOperation;
 import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.SelectExistingElementForTargetOperation;
 import org.eclipse.jface.viewers.ILabelProvider;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.widgets.Display;

 /**
  * <p>
  * A command that pops up a menu which can allow the user to select the type of
  * connection to be created and whether they want to create a new type or select
  * an existing element for the other end of the connection.
  * </p>
  *
  * <p>
  * The <code>getRelationshipTypeAdapter()</code> method returns an adaptable
  * to the relationship type result.
  * </p>
  *
  * <p>
  * The <code>getEndAdapter()</code> method returns an adaptable to the end
  * type result.
  * </p>
  *
  * @author cmahoney
  */
 public class PromptForConnectionAndEndCommand
 	extends PopupMenuCommand {

 	/**
 	 * Label provider of the first popup menu with the relationship types.
 	 */
 	protected class ConnectionLabelProvider
 		extends ElementTypeLabelProvider {

 		/*
 		 * (non-Javadoc)
 		 *
 		 * @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
 		 */
 		public String getText(Object element) {
 			String theInputStr = null;
 			if (isDirectionReversed())
 				theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFrom;
 			else
 				theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXTo;

 			String text = NLS.bind(theInputStr, super
 				.getText(element));

 			return text;

 		}
 	}

 	/**
 	 * Label provider of the second popup (submenus) for the type of the other
 	 * end.
 	 */
 	protected class EndLabelProvider
 		extends ElementTypeLabelProvider {

 		/*
 		 * (non-Javadoc)
 		 *
 		 * @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
 		 */
 		public String getText(Object element) {
 			if (element instanceof IElementType) {
 				String theInputStr = DiagramUIMessages.ConnectionHandle_Popup_NewX;
 				String text = NLS.bind(theInputStr,
 					super.getText(element));
 				return text;
 			} else {
 				return element.toString();
 			}
 		}
 	}

 	/**
 	 * Label provider of the first and only popup for the type of the other end
 	 * when there is only one connection type (e.g. a single relationship type
 	 * palette tool is used).
 	 */
 	protected class ConnectionAndEndLabelProvider
 		extends ElementTypeLabelProvider {

 		/** the known connection item */
 		private Object connectionItem;

 		/**
 		 * Creates a new <code>ConnectionAndEndLabelProvider</code>.
 		 *
 		 * @param connectionType
 		 *            the single known connection type
 		 */
 		protected ConnectionAndEndLabelProvider(Object connectionItem) {
 			this.connectionItem = connectionItem;
 		}

 		/*
 		 * (non-Javadoc)
 		 *
 		 * @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
 		 */
 		public String getText(Object element) {
 			String theInputStr = null;
 			if (element instanceof IElementType) {
 				if (isDirectionReversed())
 					theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFromNewY;
 				else
 					theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXToNewY;
 				String text = NLS.bind(theInputStr, new Object[] {
 					super.getText(connectionItem), super.getText(element)});
 				return text;
 			} else {
 				if (isDirectionReversed())
 					theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFromY;
 				else
 					theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXToY;
 				String text = NLS.bind(theInputStr, new Object[] {
 					super.getText(connectionItem), super.getText(element)});
 				return text;
 			}
 		}

 		/**
 		 * Gets the connection item.
 		 *
 		 * @return the connection item
 		 */
 		protected Object getConnectionItem() {
 			return connectionItem;
 		}

 	}

 	/**
 	 * This can be added to the content list to add a 'select existing' option.
 	 */
 	private static String EXISTING_ELEMENT = DiagramUIMessages.ConnectionHandle_Popup_ExistingElement;

 	/** Label provider of the popup menu for the connection types. */
 	private ConnectionLabelProvider connectionLabelProvider;

 	/** Label provider of the submenus for the other end element. */
 	private static EndLabelProvider endLabelProvider;

 	/** Adapts to the connection type result. */
 	private ObjectAdapter connectionAdapter = new ObjectAdapter();

 	/** Adapts to the other end type result. */
 	private ObjectAdapter endAdapter = new ObjectAdapter();

 	/**
 	 * The request to create a connection. It may contain the connection type or
 	 * it may be a <code>CreateUnspecifiedTypeConnectionRequest</code>.
 	 */
 	private CreateConnectionRequest request;

 	/** The container editpart to send the view request to. */
 	private IGraphicalEditPart containerEP;

 	/**
 	 * Creates a new <code>PromptForConnectionAndEndCommand</code>.
 	 *
 	 * @param request
 	 *            The request to create a connection. It may contain the
 	 *            connection type or it may be a
 	 *            <code>CreateUnspecifiedTypeConnectionRequest</code>.
 	 * @param containerEP
 	 *            The container edit part, where the view and element request to
 	 *            create the other end is sent. This is used only for testing
 	 *            that a type is valid for the other end.
 	 */
 	public PromptForConnectionAndEndCommand(CreateConnectionRequest request,
 			IGraphicalEditPart containerEP) {

 		super(DiagramUIMessages.Command_GetRelationshipTypeAndEndFromUser_Label,
 			Display.getCurrent().getActiveShell());
 		this.request = request;
 		this.containerEP = containerEP;
 	}

 	/**
 	 * Gets a list of all the connection items that will represent the
 	 * connection choices and will appear in the first part of the popup menu.
 	 *
 	 * <p>
 	 * If the objects in this are not <code>IElementTypes</code> or they
 	 * require a special label provider, then
 	 * {@link #getConnectionLabelProvider()} should be overridden to provide
 	 * this.
 	 * </p>
 	 * <p>
 	 * When this command has executed, the connection adapter result ({@link #getConnectionAdapter()})
 	 * will be populated with the connection item chosen.
 	 * </p>
 	 *
 	 * @return the list of connection items to appear in the popup menu
 	 */
 	protected List getConnectionMenuContent() {
 		List validRelTypes = new ArrayList();
 		if (request instanceof CreateUnspecifiedTypeConnectionRequest) {
 			List allRelTypes = null;
 			if (((CreateUnspecifiedTypeConnectionRequest) request)
 				.useModelingAssistantService()) {
 				allRelTypes = isDirectionReversed() ? ModelingAssistantService
 					.getInstance().getRelTypesOnTarget(getKnownEnd())
 					: ModelingAssistantService.getInstance()
 						.getRelTypesOnSource(getKnownEnd());
 			} else {
 				allRelTypes = ((CreateUnspecifiedTypeConnectionRequest) request)
 					.getElementTypes();
 			}

 			if (isDirectionReversed()) {
 				validRelTypes = allRelTypes;
 			} else {
 				// Cycle through and make sure each connection type is
 				// supported
 				// for starting a connection on the source.
 				for (Iterator iter = allRelTypes.iterator(); iter.hasNext();) {
 					IElementType rType = (IElementType) iter.next();
 					if (((CreateConnectionRequest) ((CreateUnspecifiedTypeConnectionRequest) request)
 						.getRequestForType(rType)).getStartCommand() != null) {
 						validRelTypes.add(rType);
 					}
 				}
 			}

 		} else if (request instanceof CreateConnectionViewAndElementRequest) {
 			if (((CreateConnectionViewAndElementRequest) request)
 				.getStartCommand() != null) {
 				validRelTypes
 					.add(((CreateRelationshipRequest) ((CreateConnectionViewAndElementRequest) request)
 						.getConnectionViewAndElementDescriptor()
 						.getCreateElementRequestAdapter().getAdapter(
 							CreateRelationshipRequest.class)).getElementType());
 			}
 		} else if (request instanceof CreateConnectionViewRequest) {
 			if (((CreateConnectionViewRequest) request).getStartCommand() != null) {
 				Object type = ((CreateConnectionViewRequest) request)
 					.getConnectionViewDescriptor().getElementAdapter()
 					.getAdapter(IElementType.class);
 				if (type != null) {
 					validRelTypes.add(type);
 				}
 			}
 		}
 		return validRelTypes;
 	}

 	/**
 	 * Gets a list of all the end items that will represent the other end
 	 * choices and will appear in the submenu popup of the given connection
 	 * item.
 	 *
 	 * <p>
 	 * If the objects in this are not <code>IElementTypes</code> or they
 	 * require a special label provider, then {@link #getEndLabelProvider()}
 	 * should be overridden to provide this.
 	 * </p>
 	 * <p>
 	 * When this command has executed, the end adapter result ({@link #getEndAdapter()})
 	 * will be populated with the end item chosen.
 	 * </p>
 	 *
 	 * @param connectionItem
 	 *            the connection item for which this will be a submenu
 	 * @return the list of end items to appear in the popup menu
 	 */
 	protected List getEndMenuContent(Object connectionItem) {
 		if (connectionItem instanceof IElementType) {
 			IElementType connectionType = (IElementType) connectionItem;
 			List menuContent = isDirectionReversed() ? ModelingAssistantService
 				.getInstance().getTypesForSource(getKnownEnd(), connectionType)
 				: ModelingAssistantService.getInstance().getTypesForTarget(
 					getKnownEnd(), connectionType);

 			menuContent = filterUnsupportedNodeTypes(menuContent);

 			if (!menuContent.isEmpty()
 				&& supportsExistingElement(connectionType)) {
 				menuContent.add(EXISTING_ELEMENT);
 			}

 			return menuContent;
 		}
 		return Collections.EMPTY_LIST;
 	}

 	/**
 	 * Gets the content to be used in the popup menu from the Modeling Assistant
 	 * Service and creates the popup menu.
 	 *
 	 * @return the top-level popup menu
 	 */
 	protected PopupMenu createPopupMenu() {

 		final List connectionMenuContent = getConnectionMenuContent();

 		if (connectionMenuContent == null || connectionMenuContent.isEmpty()) {
 			return null;
 		} else if (connectionMenuContent.size() == 1) {
 			List menuContent = getEndMenuContent(connectionMenuContent.get(0));
 			if (menuContent == null || menuContent.isEmpty()) {
 				return null;
 			}

 			ILabelProvider labelProvider = getConnectionAndEndLabelProvider(connectionMenuContent
 				.get(0));
 			return new PopupMenu(menuContent, labelProvider) {

 				/**
 				 * @see org.eclipse.gmf.runtime.diagram.ui.menus.PopupMenu#getResult()
 				 */
 				public Object getResult() {
 					Object endResult = super.getResult();
 					if (endResult == null) {
 						return null;
 					} else {
 						List resultList = new ArrayList(2);
 						resultList.add(connectionMenuContent.get(0));
 						resultList.add(endResult);
 						return resultList;
 					}
 				}
 			};
 		} else {
 			List menuContent = new ArrayList();
 			for (Iterator iter = connectionMenuContent.iterator(); iter
 				.hasNext();) {
 				Object connectionItem = iter.next();

 				List subMenuContent = getEndMenuContent(connectionItem);

 				if (subMenuContent.isEmpty()) {
 					continue;
 				}

 				PopupMenu subMenu = new PopupMenu(subMenuContent,
 					getEndLabelProvider());

 				menuContent.add(new PopupMenu.CascadingMenu(connectionItem,
 					subMenu));
 			}
 			if (!menuContent.isEmpty()) {
 				return new PopupMenu(menuContent, getConnectionLabelProvider());
 			}
 		}
 		return null;
 	}

 	/**
 	 * Returns a new list with all the types from the list given that can be
 	 * created.
 	 *
 	 * @param allTypes
 	 *            a list of <code>IElementTypes</code>.
 	 */
 	private List filterUnsupportedNodeTypes(List allTypes) {
 		List validTypes = new ArrayList();
 		for (Iterator iter = allTypes.iterator(); iter.hasNext();) {
 			IElementType type = (IElementType) iter.next();
 			Request createRequest = CreateViewRequestFactory
 				.getCreateShapeRequest(type, containerEP
 					.getDiagramPreferencesHint());

 			EditPart target = containerEP.getTargetEditPart(createRequest);
 			if (target != null) {
 				Command cmd = target.getCommand(createRequest);
 				if (cmd != null && cmd.canExecute()) {
 					validTypes.add(type);
 				}
 			}
 		}
 		return validTypes;
 	}

     public boolean canExecute() {
 		return createPopupMenu() != null;
 	}

 	/**
 	 * Pops up the dialog with the content provided. If the user selects 'select
 	 * existing', then the select elements dialog also appears.
 	 */
 	protected CommandResult doExecuteWithResult(IProgressMonitor progressMonitor,
             IAdaptable info)
         throws ExecutionException {

 		PopupMenu popup = createPopupMenu();

 		if (popup == null) {
 			return CommandResult.newErrorCommandResult(getLabel());
 		}

 		setPopupMenu(popup);

 		CommandResult cmdResult = super.doExecuteWithResult(progressMonitor, info);
 		if (!cmdResult.getStatus().isOK()) {
 			return cmdResult;
 		}

 		Object result = cmdResult.getReturnValue();
 		if (result instanceof List) {
 			List resultList = (List) result;
 			if (resultList.size() == 2) {
 				connectionAdapter.setObject(resultList.get(0));

 				Object targetResult = resultList.get(1);

 				if (targetResult.equals(EXISTING_ELEMENT)) {
 					targetResult = isDirectionReversed() ? ModelingAssistantService
 						.getInstance().selectExistingElementForSource(
 							getKnownEnd(), (IElementType) resultList.get(0))
 						: ModelingAssistantService.getInstance()
 							.selectExistingElementForTarget(getKnownEnd(),
 								(IElementType) resultList.get(0));
 					if (targetResult == null) {
 						return CommandResult.newCancelledCommandResult();
 					}
 				}
 				endAdapter.setObject(targetResult);
 				return CommandResult.newOKCommandResult();
 			}
 		}
 		return CommandResult.newErrorCommandResult(getLabel());
 	}

 	/**
 	 * Checks if the <code>ModelingAssistantService</code> supports the
 	 * ability to open a dialog for the user to select an existing element
 	 *
 	 * @param connectionType
 	 * @return true if the supported by the modeling assistant service; false
 	 *         otherwise
 	 */
 	private boolean supportsExistingElement(IElementType connectionType) {
 		if (isDirectionReversed()) {
 			if (ModelingAssistantService.getInstance().provides(
 				new SelectExistingElementForSourceOperation(getKnownEnd(),
 					connectionType))) {
 				return true;
 			}
 		} else if (ModelingAssistantService.getInstance().provides(
 			new SelectExistingElementForTargetOperation(getKnownEnd(),
 				connectionType))) {
 			return true;
 		}
 		return false;
 	}

 	/**
 	 * Gets the connectionAdapter.
 	 *
 	 * @return Returns the connectionAdapter.
 	 */
 	public ObjectAdapter getConnectionAdapter() {
 		return connectionAdapter;
 	}

 	/**
 	 * Gets the endAdapter.
 	 *
 	 * @return Returns the endAdapter.
 	 */
 	public IAdaptable getEndAdapter() {
 		return endAdapter;
 	}

 	/**
 	 * Returns true if the request is a reversed
 	 * <code>CreateUnspecifiedTypeConnectionRequest</code>.
 	 *
 	 * @return Returns true if the request is a reversed
 	 *         <code>CreateUnspecifiedTypeConnectionRequest</code>; false
 	 *         otherwise
 	 */
 	protected boolean isDirectionReversed() {
 		return (request instanceof CreateUnspecifiedTypeConnectionRequest && ((CreateUnspecifiedTypeConnectionRequest) request)
 			.isDirectionReversed());
 	}

 	/**
 	 * Gets the known end, which even in the case of a reversed
 	 * <code>CreateUnspecifiedTypeConnectionRequest</code>, is the source
 	 * editpart.
 	 *
 	 * @return the known end
 	 */
 	private EditPart getKnownEnd() {
 		return request.getSourceEditPart();
 	}

 	/**
 	 * Gets the label provider that is to be used in the first menu of the popup
 	 * where the user is to choose the connection to be created.
 	 *
 	 * @return the connection label provider
 	 */
 	protected ILabelProvider getConnectionLabelProvider() {
 		if (connectionLabelProvider == null) {
 			connectionLabelProvider = new ConnectionLabelProvider();
 		}
 		return connectionLabelProvider;
 	}

 	/**
 	 * Gets the label provider that is to be used in the second menu of the
 	 * popup where the user is to choose the end (could be source or target) to
 	 * be created.
 	 *
 	 * @return the end label provider
 	 */
 	protected ILabelProvider getEndLabelProvider() {
 		if (endLabelProvider == null) {
 			endLabelProvider = new EndLabelProvider();
 		}
 		return endLabelProvider;
 	}

 	/**
 	 * Gets the label provider that is to be used when there is only one option
 	 * for the connection type so the popup menu consists of a single menu
 	 * identifying the connection type to be created and options for the other
 	 * end of which the user must choose
 	 *
 	 * @param connectionItem
 	 *            the single known connection item
 	 * @return the label provider
 	 */
 	protected ILabelProvider getConnectionAndEndLabelProvider(
 			Object connectionItem) {
 		return new ConnectionAndEndLabelProvider(connectionItem);
 	}

 }
	/******************************************************************************
	* Copyright (c) 2005, 2006 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.gmf.runtime.diagram.ui.commands;

	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Iterator;
	import java.util.List;

	import org.eclipse.core.commands.ExecutionException;
	import org.eclipse.core.runtime.IAdaptable;
	import org.eclipse.core.runtime.IProgressMonitor;
	import org.eclipse.gef.EditPart;
	import org.eclipse.gef.Request;
	import org.eclipse.gef.commands.Command;
	import org.eclipse.gef.requests.CreateConnectionRequest;
	import org.eclipse.gmf.runtime.common.core.command.CommandResult;
	import org.eclipse.gmf.runtime.common.core.util.ObjectAdapter;
	import org.eclipse.gmf.runtime.diagram.ui.editparts.IGraphicalEditPart;
	import org.eclipse.gmf.runtime.diagram.ui.internal.commands.ElementTypeLabelProvider;
	import org.eclipse.gmf.runtime.diagram.ui.l10n.DiagramUIMessages;
	import org.eclipse.gmf.runtime.diagram.ui.menus.PopupMenu;
	import org.eclipse.gmf.runtime.diagram.ui.requests.CreateConnectionViewAndElementRequest;
	import org.eclipse.gmf.runtime.diagram.ui.requests.CreateConnectionViewRequest;
	import org.eclipse.gmf.runtime.diagram.ui.requests.CreateUnspecifiedTypeConnectionRequest;
	import org.eclipse.gmf.runtime.diagram.ui.requests.CreateViewRequestFactory;
	import org.eclipse.gmf.runtime.emf.type.core.IElementType;
	import org.eclipse.gmf.runtime.emf.type.core.requests.CreateRelationshipRequest;
	import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.ModelingAssistantService;
	import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.SelectExistingElementForSourceOperation;
	import org.eclipse.gmf.runtime.emf.ui.services.modelingassistant.SelectExistingElementForTargetOperation;
	import org.eclipse.jface.viewers.ILabelProvider;
	import org.eclipse.osgi.util.NLS;
	import org.eclipse.swt.widgets.Display;

	/**
	* <p>
	* A command that pops up a menu which can allow the user to select the type of
	* connection to be created and whether they want to create a new type or select
	* an existing element for the other end of the connection.
	* </p>
	*
	* <p>
	* The <code>getRelationshipTypeAdapter()</code> method returns an adaptable
	* to the relationship type result.
	* </p>
	*
	* <p>
	* The <code>getEndAdapter()</code> method returns an adaptable to the end
	* type result.
	* </p>
	*
	* @author cmahoney
	*/
	public class PromptForConnectionAndEndCommand
	extends PopupMenuCommand {

	/**
	* Label provider of the first popup menu with the relationship types.
	*/
	protected class ConnectionLabelProvider
	extends ElementTypeLabelProvider {

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
	*/
	public String getText(Object element) {
	String theInputStr = null;
	if (isDirectionReversed())
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFrom;
	else
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXTo;

	String text = NLS.bind(theInputStr, super
	.getText(element));

	return text;

	}
	}

	/**
	* Label provider of the second popup (submenus) for the type of the other
	* end.
	*/
	protected class EndLabelProvider
	extends ElementTypeLabelProvider {

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
	*/
	public String getText(Object element) {
	if (element instanceof IElementType) {
	String theInputStr = DiagramUIMessages.ConnectionHandle_Popup_NewX;
	String text = NLS.bind(theInputStr,
	super.getText(element));
	return text;
	} else {
	return element.toString();
	}
	}
	}

	/**
	* Label provider of the first and only popup for the type of the other end
	* when there is only one connection type (e.g. a single relationship type
	* palette tool is used).
	*/
	protected class ConnectionAndEndLabelProvider
	extends ElementTypeLabelProvider {

	/** the known connection item */
	private Object connectionItem;

	/**
	* Creates a new <code>ConnectionAndEndLabelProvider</code>.
	*
	* @param connectionType
	* the single known connection type
	*/
	protected ConnectionAndEndLabelProvider(Object connectionItem) {
	this.connectionItem = connectionItem;
	}

	/*
	* (non-Javadoc)
	*
	* @see org.eclipse.jface.viewers.ILabelProvider#getText(java.lang.Object)
	*/
	public String getText(Object element) {
	String theInputStr = null;
	if (element instanceof IElementType) {
	if (isDirectionReversed())
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFromNewY;
	else
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXToNewY;
	String text = NLS.bind(theInputStr, new Object[] {
	super.getText(connectionItem), super.getText(element)});
	return text;
	} else {
	if (isDirectionReversed())
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXFromY;
	else
	theInputStr = DiagramUIMessages.ConnectionHandle_Popup_CreateXToY;
	String text = NLS.bind(theInputStr, new Object[] {
	super.getText(connectionItem), super.getText(element)});
	return text;
	}
	}

	/**
	* Gets the connection item.
	*
	* @return the connection item
	*/
	protected Object getConnectionItem() {
	return connectionItem;
	}

	}

	/**
	* This can be added to the content list to add a 'select existing' option.
	*/
	private static String EXISTING_ELEMENT = DiagramUIMessages.ConnectionHandle_Popup_ExistingElement;

	/** Label provider of the popup menu for the connection types. */
	private ConnectionLabelProvider connectionLabelProvider;

	/** Label provider of the submenus for the other end element. */
	private static EndLabelProvider endLabelProvider;

	/** Adapts to the connection type result. */
	private ObjectAdapter connectionAdapter = new ObjectAdapter();

	/** Adapts to the other end type result. */
	private ObjectAdapter endAdapter = new ObjectAdapter();

	/**
	* The request to create a connection. It may contain the connection type or
	* it may be a <code>CreateUnspecifiedTypeConnectionRequest</code>.
	*/
	private CreateConnectionRequest request;

	/** The container editpart to send the view request to. */
	private IGraphicalEditPart containerEP;

	/**
	* Creates a new <code>PromptForConnectionAndEndCommand</code>.
	*
	* @param request
	* The request to create a connection. It may contain the
	* connection type or it may be a
	* <code>CreateUnspecifiedTypeConnectionRequest</code>.
	* @param containerEP
	* The container edit part, where the view and element request to
	* create the other end is sent. This is used only for testing
	* that a type is valid for the other end.
	*/
	public PromptForConnectionAndEndCommand(CreateConnectionRequest request,
	IGraphicalEditPart containerEP) {

	super(DiagramUIMessages.Command_GetRelationshipTypeAndEndFromUser_Label,
	Display.getCurrent().getActiveShell());
	this.request = request;
	this.containerEP = containerEP;
	}

	/**
	* Gets a list of all the connection items that will represent the
	* connection choices and will appear in the first part of the popup menu.
	*
	* <p>
	* If the objects in this are not <code>IElementTypes</code> or they
	* require a special label provider, then
	* {@link #getConnectionLabelProvider()} should be overridden to provide
	* this.
	* </p>
	* <p>
	* When this command has executed, the connection adapter result ({@link #getConnectionAdapter()})
	* will be populated with the connection item chosen.
	* </p>
	*
	* @return the list of connection items to appear in the popup menu
	*/
	protected List getConnectionMenuContent() {
	List validRelTypes = new ArrayList();
	if (request instanceof CreateUnspecifiedTypeConnectionRequest) {
	List allRelTypes = null;
	if (((CreateUnspecifiedTypeConnectionRequest) request)
	.useModelingAssistantService()) {
	allRelTypes = isDirectionReversed() ? ModelingAssistantService
	.getInstance().getRelTypesOnTarget(getKnownEnd())
	: ModelingAssistantService.getInstance()
	.getRelTypesOnSource(getKnownEnd());
	} else {
	allRelTypes = ((CreateUnspecifiedTypeConnectionRequest) request)
	.getElementTypes();
	}

	if (isDirectionReversed()) {
	validRelTypes = allRelTypes;
	} else {
	// Cycle through and make sure each connection type is
	// supported
	// for starting a connection on the source.
	for (Iterator iter = allRelTypes.iterator(); iter.hasNext();) {
	IElementType rType = (IElementType) iter.next();
	if (((CreateConnectionRequest) ((CreateUnspecifiedTypeConnectionRequest) request)
	.getRequestForType(rType)).getStartCommand() != null) {
	validRelTypes.add(rType);
	}
	}
	}

	} else if (request instanceof CreateConnectionViewAndElementRequest) {
	if (((CreateConnectionViewAndElementRequest) request)
	.getStartCommand() != null) {
	validRelTypes
	.add(((CreateRelationshipRequest) ((CreateConnectionViewAndElementRequest) request)
	.getConnectionViewAndElementDescriptor()
	.getCreateElementRequestAdapter().getAdapter(
	CreateRelationshipRequest.class)).getElementType());
	}
	} else if (request instanceof CreateConnectionViewRequest) {
	if (((CreateConnectionViewRequest) request).getStartCommand() != null) {
	Object type = ((CreateConnectionViewRequest) request)
	.getConnectionViewDescriptor().getElementAdapter()
	.getAdapter(IElementType.class);
	if (type != null) {
	validRelTypes.add(type);
	}
	}
	}
	return validRelTypes;
	}

	/**
	* Gets a list of all the end items that will represent the other end
	* choices and will appear in the submenu popup of the given connection
	* item.
	*
	* <p>
	* If the objects in this are not <code>IElementTypes</code> or they
	* require a special label provider, then {@link #getEndLabelProvider()}
	* should be overridden to provide this.
	* </p>
	* <p>
	* When this command has executed, the end adapter result ({@link #getEndAdapter()})
	* will be populated with the end item chosen.
	* </p>
	*
	* @param connectionItem
	* the connection item for which this will be a submenu
	* @return the list of end items to appear in the popup menu
	*/
	protected List getEndMenuContent(Object connectionItem) {
	if (connectionItem instanceof IElementType) {
	IElementType connectionType = (IElementType) connectionItem;
	List menuContent = isDirectionReversed() ? ModelingAssistantService
	.getInstance().getTypesForSource(getKnownEnd(), connectionType)
	: ModelingAssistantService.getInstance().getTypesForTarget(
	getKnownEnd(), connectionType);

	menuContent = filterUnsupportedNodeTypes(menuContent);

	if (!menuContent.isEmpty()
	&& supportsExistingElement(connectionType)) {
	menuContent.add(EXISTING_ELEMENT);
	}

	return menuContent;
	}
	return Collections.EMPTY_LIST;
	}

	/**
	* Gets the content to be used in the popup menu from the Modeling Assistant
	* Service and creates the popup menu.
	*
	* @return the top-level popup menu
	*/
	protected PopupMenu createPopupMenu() {

	final List connectionMenuContent = getConnectionMenuContent();

	if (connectionMenuContent == null \|\| connectionMenuContent.isEmpty()) {
	return null;
	} else if (connectionMenuContent.size() == 1) {
	List menuContent = getEndMenuContent(connectionMenuContent.get(0));
	if (menuContent == null \|\| menuContent.isEmpty()) {
	return null;
	}

	ILabelProvider labelProvider = getConnectionAndEndLabelProvider(connectionMenuContent
	.get(0));
	return new PopupMenu(menuContent, labelProvider) {

	/**
	* @see org.eclipse.gmf.runtime.diagram.ui.menus.PopupMenu#getResult()
	*/
	public Object getResult() {
	Object endResult = super.getResult();
	if (endResult == null) {
	return null;
	} else {
	List resultList = new ArrayList(2);
	resultList.add(connectionMenuContent.get(0));
	resultList.add(endResult);
	return resultList;
	}
	}
	};
	} else {
	List menuContent = new ArrayList();
	for (Iterator iter = connectionMenuContent.iterator(); iter
	.hasNext();) {
	Object connectionItem = iter.next();

	List subMenuContent = getEndMenuContent(connectionItem);

	if (subMenuContent.isEmpty()) {
	continue;
	}

	PopupMenu subMenu = new PopupMenu(subMenuContent,
	getEndLabelProvider());

	menuContent.add(new PopupMenu.CascadingMenu(connectionItem,
	subMenu));
	}
	if (!menuContent.isEmpty()) {
	return new PopupMenu(menuContent, getConnectionLabelProvider());
	}
	}
	return null;
	}

	/**
	* Returns a new list with all the types from the list given that can be
	* created.
	*
	* @param allTypes
	* a list of <code>IElementTypes</code>.
	*/
	private List filterUnsupportedNodeTypes(List allTypes) {
	List validTypes = new ArrayList();
	for (Iterator iter = allTypes.iterator(); iter.hasNext();) {
	IElementType type = (IElementType) iter.next();
	Request createRequest = CreateViewRequestFactory
	.getCreateShapeRequest(type, containerEP
	.getDiagramPreferencesHint());

	EditPart target = containerEP.getTargetEditPart(createRequest);
	if (target != null) {
	Command cmd = target.getCommand(createRequest);
	if (cmd != null && cmd.canExecute()) {
	validTypes.add(type);
	}
	}
	}
	return validTypes;
	}

	public boolean canExecute() {
	return createPopupMenu() != null;
	}

	/**
	* Pops up the dialog with the content provided. If the user selects 'select
	* existing', then the select elements dialog also appears.
	*/
	protected CommandResult doExecuteWithResult(IProgressMonitor progressMonitor,
	IAdaptable info)
	throws ExecutionException {

	PopupMenu popup = createPopupMenu();

	if (popup == null) {
	return CommandResult.newErrorCommandResult(getLabel());
	}

	setPopupMenu(popup);

	CommandResult cmdResult = super.doExecuteWithResult(progressMonitor, info);
	if (!cmdResult.getStatus().isOK()) {
	return cmdResult;
	}

	Object result = cmdResult.getReturnValue();
	if (result instanceof List) {
	List resultList = (List) result;
	if (resultList.size() == 2) {
	connectionAdapter.setObject(resultList.get(0));

	Object targetResult = resultList.get(1);

	if (targetResult.equals(EXISTING_ELEMENT)) {
	targetResult = isDirectionReversed() ? ModelingAssistantService
	.getInstance().selectExistingElementForSource(
	getKnownEnd(), (IElementType) resultList.get(0))
	: ModelingAssistantService.getInstance()
	.selectExistingElementForTarget(getKnownEnd(),
	(IElementType) resultList.get(0));
	if (targetResult == null) {
	return CommandResult.newCancelledCommandResult();
	}
	}
	endAdapter.setObject(targetResult);
	return CommandResult.newOKCommandResult();
	}
	}
	return CommandResult.newErrorCommandResult(getLabel());
	}

	/**
	* Checks if the <code>ModelingAssistantService</code> supports the
	* ability to open a dialog for the user to select an existing element
	*
	* @param connectionType
	* @return true if the supported by the modeling assistant service; false
	* otherwise
	*/
	private boolean supportsExistingElement(IElementType connectionType) {
	if (isDirectionReversed()) {
	if (ModelingAssistantService.getInstance().provides(
	new SelectExistingElementForSourceOperation(getKnownEnd(),
	connectionType))) {
	return true;
	}
	} else if (ModelingAssistantService.getInstance().provides(
	new SelectExistingElementForTargetOperation(getKnownEnd(),
	connectionType))) {
	return true;
	}
	return false;
	}

	/**
	* Gets the connectionAdapter.
	*
	* @return Returns the connectionAdapter.
	*/
	public ObjectAdapter getConnectionAdapter() {
	return connectionAdapter;
	}

	/**
	* Gets the endAdapter.
	*
	* @return Returns the endAdapter.
	*/
	public IAdaptable getEndAdapter() {
	return endAdapter;
	}

	/**
	* Returns true if the request is a reversed
	* <code>CreateUnspecifiedTypeConnectionRequest</code>.
	*
	* @return Returns true if the request is a reversed
	* <code>CreateUnspecifiedTypeConnectionRequest</code>; false
	* otherwise
	*/
	protected boolean isDirectionReversed() {
	return (request instanceof CreateUnspecifiedTypeConnectionRequest && ((CreateUnspecifiedTypeConnectionRequest) request)
	.isDirectionReversed());
	}

	/**
	* Gets the known end, which even in the case of a reversed
	* <code>CreateUnspecifiedTypeConnectionRequest</code>, is the source
	* editpart.
	*
	* @return the known end
	*/
	private EditPart getKnownEnd() {
	return request.getSourceEditPart();
	}

	/**
	* Gets the label provider that is to be used in the first menu of the popup
	* where the user is to choose the connection to be created.
	*
	* @return the connection label provider
	*/
	protected ILabelProvider getConnectionLabelProvider() {
	if (connectionLabelProvider == null) {
	connectionLabelProvider = new ConnectionLabelProvider();
	}
	return connectionLabelProvider;
	}

	/**
	* Gets the label provider that is to be used in the second menu of the
	* popup where the user is to choose the end (could be source or target) to
	* be created.
	*
	* @return the end label provider
	*/
	protected ILabelProvider getEndLabelProvider() {
	if (endLabelProvider == null) {
	endLabelProvider = new EndLabelProvider();
	}
	return endLabelProvider;
	}

	/**
	* Gets the label provider that is to be used when there is only one option
	* for the connection type so the popup menu consists of a single menu
	* identifying the connection type to be created and options for the other
	* end of which the user must choose
	*
	* @param connectionItem
	* the single known connection item
	* @return the label provider
	*/
	protected ILabelProvider getConnectionAndEndLabelProvider(
	Object connectionItem) {
	return new ConnectionAndEndLabelProvider(connectionItem);
	}

	}