modeling/plugins/org.eclipse.pde.emfforms/src/org/eclipse/pde/emfforms/editor/actions/RemoveAction.java

/**
 * Copyright (c) 2010 Sierra Wireless 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:
 *     Jacques Lescot, Sierra Wireless - initial API and implementation (bug 300462)
 *
 * $Id: RemoveAction.java,v 1.1 2010/01/22 16:42:08 bcabe Exp $
 */
package org.eclipse.pde.emfforms.editor.actions;

import java.util.List;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.ecore.EStructuralFeature;
import org.eclipse.emf.edit.ui.action.EditingDomainActionBarContributor;
import org.eclipse.jface.action.Action;
import org.eclipse.jface.action.IAction;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.util.IPropertyChangeListener;
import org.eclipse.jface.viewers.StructuredSelection;
import org.eclipse.jface.viewers.TreeViewer;
import org.eclipse.pde.emfforms.editor.EmfActionBarContributor;
import org.eclipse.pde.emfforms.editor.EmfMasterDetailBlock;
import org.eclipse.pde.emfforms.internal.Activator;
import org.eclipse.pde.emfforms.internal.editor.IEmfFormsImages;

public class RemoveAction extends Action {

	public void addPropertyChangeListener(IPropertyChangeListener listener) {
		getDeleteAction().addPropertyChangeListener(listener);
	}

	public int getAccelerator() {
		return getDeleteAction().getAccelerator();
	}

	public String getActionDefinitionId() {
		return getDeleteAction().getActionDefinitionId();
	}

	public String getDescription() {
		return getDeleteAction().getDescription();
	}

	public String getToolTipText() {
		return getDeleteAction().getToolTipText();
	}

	@Override
	public void setEnabled(boolean enabled) {
		getDeleteAction().setEnabled(enabled);
	}

	public boolean isEnabled() {
		return getDeleteAction().isEnabled();
	}

	@Override
	public String getText() {
		return getDeleteAction().getText();
	}

	@Override
	public void run() {
		TreeViewer treeViewer = masterDetail.getTreeViewer();

		EObject nearestEltToSelect = computeElementToSelectAfterDeletion(treeViewer);

		getDeleteAction().run();

		treeViewer.refresh();
		if (nearestEltToSelect != null) {
			treeViewer.setSelection(new StructuredSelection(nearestEltToSelect));
			treeViewer.getTree().setFocus();
		}
	}

	/**
	 * Find the next element to be selected in the tree once the delete operation has been performed
	 * 
	 * @param treeViewer The {@link TreeViewer}
	 * @return the next {@link EObject} to be selected in the tree or <code>null</code> if none found. A possible reason to that last case is because there is no remaining element to select in the tree.
	 */
	protected EObject computeElementToSelectAfterDeletion(TreeViewer treeViewer) {
		EObject nextObjToSelect = null;

		// Iterate over all the selected element to be removed to define the new element to select in the tree after the delete operation is performed. 
		List<EObject> selectedElements = (List<EObject>) ((StructuredSelection) treeViewer.getSelection()).toList();
		for (EObject eltToRemove : selectedElements) {
			EObject containerElt = eltToRemove.eContainer();
			EStructuralFeature eContainingFeature = eltToRemove.eContainingFeature();
			// Retrieve all the siblings elements and try to select the nearest one
			Object featureValue = containerElt.eGet(eContainingFeature);
			if (featureValue instanceof List<?>) {
				List<EObject> siblingElts = (List<EObject>) featureValue;
				EObject candidateElt = getSelectableElement(selectedElements, siblingElts, eltToRemove);
				if (candidateElt != null) {
					return candidateElt;
				}
			}
		}
		return nextObjToSelect;
	}

	private EObject getSelectableElement(List<EObject> eltsToRemoveList, List<EObject> siblingElts, EObject eltToRemove) {
		int indexEltToRemove = siblingElts.indexOf(eltToRemove);
		// Try to search the next element in the list
		for (int i = indexEltToRemove + 1; i < siblingElts.size(); i++) {
			if (!eltsToRemoveList.contains(siblingElts.get(i))) {
				return siblingElts.get(i);
			}
		}
		// Or search among the previous elements in the list
		for (int i = indexEltToRemove - 1; i >= 0; i--) {
			if (!eltsToRemoveList.contains(siblingElts.get(i))) {
				return siblingElts.get(i);
			}
		}
		// Or return the parent element
		if (!eltsToRemoveList.contains(eltToRemove.eContainer())) {
			return eltToRemove.eContainer();
		}
		return null;
	}

	private EmfMasterDetailBlock masterDetail;

	public RemoveAction(EmfMasterDetailBlock masterDetail) {
		super();
		this.masterDetail = masterDetail;
		getDeleteAction();

	}

	private IAction getDeleteAction() {
		EditingDomainActionBarContributor actionBarContributor = masterDetail.getEditor().getActionBarContributor();
		if (actionBarContributor != null && actionBarContributor instanceof EmfActionBarContributor)
			return ((EmfActionBarContributor) actionBarContributor).getDeleteAction();
		return null;
	}

	@Override
	public ImageDescriptor getImageDescriptor() {
		return ImageDescriptor.createFromURL(Activator.getDefault().getBundle().getResource(IEmfFormsImages.REMOVE_TOOLBAR_BUTTON));
	}
}