org.eclipse.gmf.examples.runtime.emf.clipboard/src/org/eclipse/gmf/examples/runtime/emf/clipboard/actions/PasteDelegate.java

/******************************************************************************
 * Copyright (c) 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.gmf.examples.runtime.emf.clipboard.actions;

import java.util.Collection;
import java.util.Iterator;

import org.eclipse.emf.common.command.AbstractCommand;
import org.eclipse.emf.common.command.CompoundCommand;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.resource.Resource;
import org.eclipse.emf.edit.domain.EditingDomain;
import org.eclipse.gmf.examples.runtime.emf.clipboard.internal.l10n.EMFClipboardMessages;
import org.eclipse.gmf.examples.runtime.emf.clipboard.transfer.EmfTransfer;
import org.eclipse.gmf.examples.runtime.emf.clipboard.transfer.EmfTransferType;
import org.eclipse.gmf.runtime.emf.clipboard.core.ClipboardUtil;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.swt.dnd.Clipboard;


/**
 * Action delegate for the Library-metamodel-aware Paste action.  The paste
 * action is undoable.
 */
public class PasteDelegate
	extends AbstractClipboardDelegate {

	private static final String PROBLEMS_TITLE = EMFClipboardMessages.pasteProblems_title;
	private static final String PROBLEMS_MESSAGE = EMFClipboardMessages.pasteProblems_msg;
	
	/**
	 * Initializes me.
	 */
	public PasteDelegate() {
		super();
	}

	/**
	 * Pastes elements from the clipboard.  No hints are required for this paste
	 * operation.
	 */
	protected void doRun(final Clipboard clipboard) {
		final Collection objectsPasted = new java.util.HashSet();
		
		EditingDomain domain = getEditor().getEditingDomain();
		
		CompoundCommand command = new CompoundCommand(EMFClipboardMessages.paste_label);
		
		// add a command that does the paste to the composite
		command.append(new RecordingCommand(
			domain,
			"", //$NON-NLS-1$
			new Runnable() {
				public void run() {
					doRun(clipboard, objectsPasted);
				}}));
		
		// another command to select the pasted elements.
		//    It does nothing on undo
		command.append(new SelectionCommand(objectsPasted));
		
		// execute the composite
		domain.getCommandStack().execute(command);
	}
	
	/**
	 * Implementation of the <code>Runnable</code>'s run method in the change
	 * command.
	 * 
	 * @param clipboard the clipboard to paste from
	 * @param objectsPasted accumulates the objects pasted
	 */
	void doRun(Clipboard clipboard, Collection objectsPasted) {
		boolean problems = false;
		
		// use the customer EMF data transfer type provided by this plug-in
		EmfTransferType data = (EmfTransferType) clipboard.getContents(
			EmfTransfer.getInstance());
		
		if (data != null) {
			String clipString = data.getString();
			
			// paste into each selected element
			for (Iterator iter = getSelectedObjects().iterator(); iter.hasNext();) {
				EObject target = (EObject) iter.next();
				
				Collection pasted = ClipboardUtil.pasteElementsFromString(
					clipString, target, null, null);
				
				if (pasted == null || pasted.isEmpty()) {
					problems = true;
				} else {
					objectsPasted.addAll(pasted);
				}
			}

			// paste into each selected resource
			for (Iterator iter = getSelectedResources().iterator(); iter.hasNext();) {
				Resource target = (Resource) iter.next();
				
				Collection pasted = ClipboardUtil.pasteElementsFromString(
					clipString, target, null, null);
				
				if (pasted == null || pasted.isEmpty()) {
					problems = true;
				} else {
					objectsPasted.addAll(pasted);
				}
			}
		}
		
		if (problems) {
			MessageDialog.openInformation(
				getShell(), PROBLEMS_TITLE, PROBLEMS_MESSAGE);
		}
	}
	

	/* (non-Javadoc)
	 * @see org.eclipse.ui.IActionDelegate#selectionChanged(org.eclipse.jface.action.IAction, org.eclipse.jface.viewers.ISelection)
	 */
	public void selectionChanged(IAction action, final ISelection selection) {
		super.selectionChanged(action, selection);
		if (!action.isEnabled()) {
			action.setEnabled(!getSelectedResources().isEmpty());
		}
	}

	/**
	 * A command that selects a collection of elements in the editor whenever
	 * it is executed or redone.
	 */
	private class SelectionCommand extends AbstractCommand {
		private Collection elementsToSelect;
		
		/**
		 * Initializes me with the <code>elements</code> to select.
		 * 
		 * @param elements the elements to select
		 */
		SelectionCommand(Collection elements) {
			this.elementsToSelect = elements;
		}
		
		public void execute() {
			selectInEditor(elementsToSelect);
		}

		public void redo() {
			execute();
		}
		
		public void undo() {
			// undo is a no-op (deleting the pasted objects
			//     unselects them, anyway)
		}
		
		protected boolean prepare() {
			return true;  // nothing to prepare
		}
		
		public void dispose() {
			elementsToSelect = null;
		}
	}
}