plugins/org.eclipse.graphiti.ui/src/org/eclipse/graphiti/ui/features/DefaultDeleteFeature.java

/*******************************************************************************
 * <copyright>
 *
 * Copyright (c) 2005, 2014 SAP AG.
 * 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:
 *    SAP AG - initial API, implementation and documentation
 *    mwenz - Bug 347421 - Make setDoneChanges accessible to sub classes
 *    Benjamin Schmeling - mwenz - Bug 367483 - Support composite connections
 *    mgorning - Bug 376572 - Generic context buttons name changeable via getName() method
 *    mwenz - Bug 453553 - Provide an abort possibility for delete and remove features in case 'pre' methods fail
 *
 * </copyright>
 *
 *******************************************************************************/
package org.eclipse.graphiti.ui.features;

import java.text.MessageFormat;
import java.util.ArrayList;
import java.util.List;

import org.eclipse.core.runtime.OperationCanceledException;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.util.EcoreUtil;
import org.eclipse.graphiti.features.IDeleteFeature;
import org.eclipse.graphiti.features.IFeatureProvider;
import org.eclipse.graphiti.features.IRemoveFeature;
import org.eclipse.graphiti.features.context.IContext;
import org.eclipse.graphiti.features.context.IDeleteContext;
import org.eclipse.graphiti.features.context.IMultiDeleteInfo;
import org.eclipse.graphiti.features.context.IRemoveContext;
import org.eclipse.graphiti.features.context.impl.RemoveContext;
import org.eclipse.graphiti.features.impl.AbstractFeature;
import org.eclipse.graphiti.mm.pictograms.CompositeConnection;
import org.eclipse.graphiti.mm.pictograms.Connection;
import org.eclipse.graphiti.mm.pictograms.PictogramElement;
import org.eclipse.graphiti.ui.internal.Messages;
import org.eclipse.jface.dialogs.MessageDialog;
import org.eclipse.ui.PlatformUI;

/**
 * The Graphiti default implementation of the {@link IDeleteFeature}. It cares
 * about removing the shape(s) representing the deleted domain object(s) from
 * the diagram (by delegating to the {@link IRemoveFeature} provided by the
 * {@link IFeatureProvider}. After that the EMF domain objects will be deleted
 * using standard EMF functionality.<br>
 * Before the deletion process starts the tool user will be asked if he really
 * wants to delete; the popup appears only once for multi object deletions.
 */
public class DefaultDeleteFeature extends AbstractFeature implements IDeleteFeature {

	private static final String NAME = Messages.DefaultDeleteFeature_1_xfld;
	private static final String DESC = org.eclipse.graphiti.internal.Messages.ContextEntryHelper_5_xfld;

	private boolean doneChanges = false;

	/**
	 * Creates a new {@link DefaultDeleteFeature}.
	 * 
	 * @param fp
	 *            the feature provider
	 */
	public DefaultDeleteFeature(IFeatureProvider fp) {
		super(fp);
	}

	/*
	 * @see
	 * org.eclipse.graphiti.func.IDelete#canDelete(org.eclipse.graphiti.features
	 * .context.IDeleteContext)
	 */
	public boolean canDelete(IDeleteContext context) {
		PictogramElement pictogramElement = context.getPictogramElement();
		IRemoveContext rc = new RemoveContext(pictogramElement);
		IRemoveFeature removeFeature = getFeatureProvider().getRemoveFeature(rc);
		boolean ret = (removeFeature != null) && removeFeature.canRemove(rc);
		return ret;
	}

	/*
	 * @see
	 * org.eclipse.graphiti.func.IDelete#delete(org.eclipse.graphiti.features
	 * .context.IDeleteContext)
	 */
	public void delete(IDeleteContext context) {
		// we need this reset, since the an instance of this feature can be
		// used multiple times, e.g. as a part of a pattern
		setDoneChanges(false);

		IMultiDeleteInfo multiDeleteInfo = context.getMultiDeleteInfo();
		if (multiDeleteInfo != null && multiDeleteInfo.isDeleteCanceled()) {
			return;
		}
		PictogramElement pe = context.getPictogramElement();
		Object[] businessObjectsForPictogramElement = getAllBusinessObjectsForPictogramElement(pe);
		if (businessObjectsForPictogramElement != null && businessObjectsForPictogramElement.length > 0) {
			if (multiDeleteInfo == null) {
				if (!getUserDecision(context)) {
					return;
				}
			} else {
				if (multiDeleteInfo.isShowDialog()) {
					boolean okPressed = getUserDecision(context);
					if (okPressed) {
						// don't show further dialogs
						multiDeleteInfo.setShowDialog(false);
					} else {
						multiDeleteInfo.setDeleteCanceled(true);
						return;
					}
				}
			}
		}

		preDelete(context);
		if (isDeleteAbort()) {
			throw new OperationCanceledException();
		}
		if (pe instanceof CompositeConnection) {
			// Find all domain objects for the children connections of the
			// composite connection...
			List<Object> compositeChildConnectionsBOs = collectCompositeConnectionsBOs((CompositeConnection) pe);
			// ... and add them to the list of BOs to delete (no duplicates)
			for (Object object : businessObjectsForPictogramElement) {
				if (!compositeChildConnectionsBOs.contains(object)) {
					compositeChildConnectionsBOs.add(object);
				}
			}
			// Update BOs to delete
			businessObjectsForPictogramElement = compositeChildConnectionsBOs
					.toArray(new Object[compositeChildConnectionsBOs.size()]);
		}
		IRemoveContext rc = new RemoveContext(pe);
		IFeatureProvider featureProvider = getFeatureProvider();
		IRemoveFeature removeFeature = featureProvider.getRemoveFeature(rc);
		if (removeFeature != null) {
			removeFeature.remove(rc);
			// Bug 347421: Set hasDoneChanges flag only after first modification
			setDoneChanges(true);
		}

		deleteBusinessObjects(businessObjectsForPictogramElement);

		postDelete(context);
	}

	private List<Object> collectCompositeConnectionsBOs(CompositeConnection composite) {
		List<Object> result = new ArrayList<Object>();
		for (Connection childConnection : composite.getChildren()) {
			Object[] allBusinessObjectsForChildConnection = getAllBusinessObjectsForPictogramElement(childConnection);
			for (Object object : allBusinessObjectsForChildConnection) {
				if (!result.contains(object)) {
					result.add(object);
				}
			}
		}
		return result;
	}

	/**
	 * Standard functionality to delete all given domain objects.
	 * 
	 * @param businessObjects
	 *            the domain objects to delete
	 */
	protected void deleteBusinessObjects(Object[] businessObjects) {
		if (businessObjects != null) {
			for (Object bo : businessObjects) {
				deleteBusinessObject(bo);
			}
		}
	}

	/**
	 * Standard functionality to delete one domain object. Will delegate for
	 * {@link EObject}s to {@link EcoreUtil#delete(EObject, boolean)}; non-EMF
	 * objects will be ignored.
	 * 
	 * @param bo
	 *            the domain object to delete
	 */
	protected void deleteBusinessObject(Object bo) {
		if (bo instanceof EObject) {
			EcoreUtil.delete((EObject) bo, true);
		}
	}

	/*
	 * @see
	 * org.eclipse.graphiti.func.IDelete#preDelete(org.eclipse.graphiti.features
	 * .context.IDeleteContext)
	 */
	public void preDelete(IDeleteContext context) {
	}

	/**
	 * @since 0.12
	 */
	@Override
	public boolean isDeleteAbort() {
		return false;
	}

	/*
	 * @see
	 * org.eclipse.graphiti.func.IDelete#postDelete(org.eclipse.graphiti.features
	 * .context.IDeleteContext)
	 */
	public void postDelete(IDeleteContext context) {
	}

	/*
	 * @see
	 * org.eclipse.graphiti.features.IFeature#canExecute(org.eclipse.graphiti
	 * .features.context.IContext)
	 */
	public boolean canExecute(IContext context) {
		boolean ret = false;
		if (context instanceof IDeleteContext) {
			ret = canDelete((IDeleteContext) context);
		}
		return ret;
	}

	/*
	 * @see
	 * org.eclipse.graphiti.features.IFeature#execute(org.eclipse.graphiti.features
	 * .context.IContext)
	 */
	public void execute(IContext context) {
		if (context instanceof IDeleteContext) {
			delete((IDeleteContext) context);
		}
	}

	/**
	 * Hook to return the name of the delete operation e.g for display in the
	 * context menu. The standard implementation simply returns "Delete".
	 * 
	 * @return The diplay name of the operation
	 */
	@Override
	public String getName() {
		return NAME;
	}

	@Override
	public String getDescription() {
		return DESC;
	}

	/*
	 * @see org.eclipse.graphiti.features.IFeature#hasDoneChanges()
	 */
	@Override
	public boolean hasDoneChanges() {
		return doneChanges;
	}

	/**
	 * Can be called by users (in subclasses of {@link DefaultDeleteFeature}) to
	 * tell the framework that changes have been done that should reflect on the
	 * command stack. The method is called by the standard implementation in
	 * {@link #delete(IDeleteContext)} right after the first shape has been
	 * removed from the diagram.
	 * 
	 * @param doneChanges
	 *            <code>true</code>in case modifications have been made,
	 *            <code>false</code> otherwise
	 * 
	 * @since 0.9
	 */
	protected void setDoneChanges(boolean doneChanges) {
		this.doneChanges = doneChanges;
	}

	/**
	 * Shows a dialog which asks the user to confirm the deletion of one or more
	 * elements.
	 * 
	 * @param context
	 *            delete context
	 * @return <code>true</code> to delete element(s); <code>false</code> to
	 *         cancel delete
	 */
	protected boolean getUserDecision(IDeleteContext context) {
		String msg;
		IMultiDeleteInfo multiDeleteInfo = context.getMultiDeleteInfo();
		if (multiDeleteInfo != null) {
			msg = MessageFormat.format(Messages.DefaultDeleteFeature_2_xmsg, multiDeleteInfo.getNumber());
		} else {
			String deleteName = getDeleteName(context);
			if (deleteName != null && deleteName.length() > 0) {
				msg = MessageFormat.format(Messages.DefaultDeleteFeature_3_xmsg, deleteName);
			} else {
				msg = Messages.DefaultDeleteFeature_4_xmsg;
			}
		}
		return MessageDialog.openQuestion(PlatformUI.getWorkbench().getActiveWorkbenchWindow().getShell(),
				Messages.DefaultDeleteFeature_5_xfld, msg);
	}

	/**
	 * Returns the delete name which will be used for the delete dialog. E.g.
	 * "file test.java". The default implementation returns <code>null</code> to
	 * indicate that the popup text refers to "this object".
	 * 
	 * @param context
	 *            the delete context
	 * @return the delete name, or <code>null</code> to indicate no special name
	 *         shall be used
	 * @since 0.8
	 */
	protected String getDeleteName(IDeleteContext context) {
		return null;
	}
}