ca.uvic.chisel.javasketch.ui.internal.presentation.commands.ToggleSketchActivationHandler.java Source code

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Here is the source code for ca.uvic.chisel.javasketch.ui.internal.presentation.commands.ToggleSketchActivationHandler.java

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/*******************************************************************************
 * Copyright (c) 2009 the CHISEL group and contributors.
 * 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:
 *     the CHISEL group - initial API and implementation
 *******************************************************************************/
package ca.uvic.chisel.javasketch.ui.internal.presentation.commands;

import java.util.Map;

import org.eclipse.core.commands.AbstractHandler;
import org.eclipse.core.commands.ExecutionEvent;
import org.eclipse.core.commands.ExecutionException;
import org.eclipse.jface.resource.ImageRegistry;
import org.eclipse.jface.viewers.ISelection;
import org.eclipse.jface.viewers.IStructuredSelection;
import org.eclipse.ui.ISelectionService;
import org.eclipse.ui.commands.IElementUpdater;
import org.eclipse.ui.handlers.HandlerUtil;
import org.eclipse.ui.menus.UIElement;

import ca.uvic.chisel.javasketch.IProgramSketch;
import ca.uvic.chisel.javasketch.SketchPlugin;
import ca.uvic.chisel.javasketch.ui.ISketchImageConstants;

/**
 * @author Del Myers
 *
 */
public class ToggleSketchActivationHandler extends AbstractHandler implements IElementUpdater {

    public static final String COMMAND_ID = "ca.uvic.chisel.javasketch.commands.toggleSketchActive";

    /* (non-Javadoc)
     * @see org.eclipse.ui.commands.IElementUpdater#updateElement(org.eclipse.ui.menus.UIElement, java.util.Map)
     */
    @SuppressWarnings("unchecked")
    @Override
    public void updateElement(UIElement element, Map parameters) {
        ISelectionService service = (ISelectionService) element.getServiceLocator()
                .getService(ISelectionService.class);
        if (service != null) {
            IProgramSketch sketch = getSelectedSketch(service.getSelection());
            if (sketch != null) {
                ImageRegistry registry = SketchPlugin.getDefault().getImageRegistry();
                if (sketch.equals(SketchPlugin.getDefault().getActiveSketch())) {
                    element.setText("Deactivate Trace");
                    element.setIcon(registry.getDescriptor(ISketchImageConstants.ICON_TRACE_INACTIVE));
                } else {
                    element.setText("Activate Trace");
                    element.setIcon(registry.getDescriptor(ISketchImageConstants.ICON_TRACE_ACTIVE));
                }
            }
        }

    }

    /* (non-Javadoc)
     * @see org.eclipse.core.commands.IHandler#execute(org.eclipse.core.commands.ExecutionEvent)
     */
    @Override
    public Object execute(ExecutionEvent event) throws ExecutionException {
        ISelection selection = HandlerUtil.getCurrentSelection(event);
        IProgramSketch sketch = getSelectedSketch(selection);
        if (sketch == null)
            return null;
        if (sketch.equals(SketchPlugin.getDefault().getActiveSketch())) {
            SketchPlugin.getDefault().setActiveSketch(null);
        } else {
            SketchPlugin.getDefault().setActiveSketch(sketch);
        }
        return null;
    }

    /**
     * @param selection
     * @return
     */
    private IProgramSketch getSelectedSketch(ISelection selection) {
        if (selection instanceof IStructuredSelection) {
            IStructuredSelection ss = (IStructuredSelection) selection;
            if (ss.getFirstElement() instanceof IProgramSketch) {
                return (IProgramSketch) ss.getFirstElement();
            }
        }
        return null;
    }

}