AbstractZoomHandler.java

/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
*      http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.motorola.studio.android.emulator.ui.handlers;

import static com.motorola.studio.android.common.log.StudioLogger.error;
import static com.motorola.studio.android.common.log.StudioLogger.info;

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.ui.IViewPart;
import org.eclipse.ui.commands.IElementUpdater;
import org.eclipse.ui.menus.UIElement;

import com.motorola.studio.android.common.utilities.EclipseUtils;
import com.motorola.studio.android.emulator.core.model.IAndroidEmulatorInstance;
import com.motorola.studio.android.emulator.i18n.EmulatorNLS;
import com.motorola.studio.android.emulator.ui.view.AbstractAndroidView;
import com.motorola.studio.android.emulator.ui.view.AndroidViewData;

/**
 * DESCRIPTION:
 * This class is a handler for the zoom actions
 *
 * RESPONSIBILITY:
 * Execute the zoom operations on demand
 *
 * COLABORATORS:
 * None.
 *
 * USAGE:
 * This class is intended to be used by Eclipse only
 */
public abstract class AbstractZoomHandler extends AbstractHandler implements IHandlerConstants,
        IElementUpdater
{
    /**
     * @see org.eclipse.core.commands.IHandler#execute(ExecutionEvent)
     */
    public Object execute(ExecutionEvent event) throws ExecutionException
    {
        String viewId = event.getParameter(ACTIVE_VIEW_PARAMETER);
        double zoomFactor = getZoomFactor(event.getParameters());

        info("Setting zoom factor for " + viewId + " = " + zoomFactor);

        IAndroidEmulatorInstance instance = AbstractAndroidView.getActiveInstance();
        if (instance != null)
        {
            IViewPart viewPart = EclipseUtils.getActiveView(viewId);
            if (viewPart instanceof AbstractAndroidView)
            {
                AbstractAndroidView view = (AbstractAndroidView) viewPart;
                if (view.getZoomFactor(instance) != zoomFactor)
                {
                    view.setZoomFactor(instance, zoomFactor);
                    view.updateActiveViewer();
                }
            }
        }
        else
        {
            error("The host being presented at the viewer is not available");
            EclipseUtils.showErrorDialog(EmulatorNLS.GEN_Error,
                    EmulatorNLS.EXC_AbstractZoomHandler_InstanceNotFound);
        }
        return null;
    }

    /**
     * When a different emulator tab have focus, then each of the zoom factor menu items need
     * to update itself so that the radio selection continues at the correct place 
     * 
     * @see org.eclipse.ui.commands.IElementUpdater#updateElement(UIElement, Map)
     */
    @SuppressWarnings("rawtypes")
    public void updateElement(UIElement element, Map parameters)
    {
        boolean checked = false;
        IAndroidEmulatorInstance instance = AbstractAndroidView.getActiveInstance();
        String viewId = (String) parameters.get(ACTIVE_VIEW_PARAMETER);

        if ((instance != null) && (viewId != null))
        {
            IViewPart viewPart = EclipseUtils.getActiveView(viewId);
            if (viewPart instanceof AbstractAndroidView)
            {
                AbstractAndroidView view = (AbstractAndroidView) viewPart;
                AndroidViewData viewData = view.getViewData(instance);

                double actualZoomFactor = view.getZoomFactor(instance);
                if (testZoomFactor(viewData, parameters, actualZoomFactor))
                {
                    checked = true;
                }
            }
        }

        element.setChecked(checked);
    }

    /**
     * The zoom actions are enabled when a phone skin is being presented only
     * 
     * @see org.eclipse.core.commands.IHandler#isEnabled()
     */
    @Override
    public boolean isEnabled()
    {
        return AbstractAndroidView.getActiveInstance() != null;
    }

    /**
     * Retrieves the zoom factor associated to this zoom handler instance
     * 
     * @return The zoom factor, as defined in IEmulatorActionConstants class
     */
    @SuppressWarnings("rawtypes")
    protected abstract double getZoomFactor(Map paramters);

    /**
     * Tests if the current zoom factor is the one handled by this zoom handler
     * 
     * @param zoomFactor The active instance current zoom factor 
     * 
     * @return True if this handler handles the current zoom factor; false otherwise
     */
    @SuppressWarnings("rawtypes")
    protected abstract boolean testZoomFactor(AndroidViewData viewData, Map parameters,
            double zoomFactor);
}