/**
 * Copyright (c) 2009-2010 Thales Corporate Services S.A.S.
 * 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:
 * Thales Corporate Services S.A.S - initial API and implementation
 */
package org.eclipse.egf.pattern.ui;

import org.eclipse.egf.common.ui.activator.EGFAbstractUIPlugin;
import org.eclipse.egf.core.pde.EGFPDEPlugin;
import org.eclipse.egf.pattern.ui.builder.FcoreListener;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.ui.IWorkbenchWindow;
import org.osgi.framework.BundleContext;

/**
 * Common plug-in activator.
 * 
 * @author Xavier Maysonnave
 */
public class Activator extends EGFAbstractUIPlugin {

  /**
   * Shared instance.
   */
  protected static Activator __plugin;

  /**
   * Get shared instance.
   * 
   * @return
   */
  public static Activator getDefault() {
    return __plugin;
  }

  /**
   * 
   * Returns the currently active window for this workbench (if any). Returns
   * <code>null</code> if there is no active workbench window. Returns
   * <code>null</code> if called from a non-UI thread.
   * 
   * @return the active workbench window, or <code>null</code> if there is
   *         no active workbench window or if called from a non-UI thread
   */
  public static IWorkbenchWindow getActiveWorkbenchWindow() {
    return getDefault().getWorkbench().getActiveWorkbenchWindow();
  }

  /**
   * Returns the currently active shell for this workbench (if any).
   * 
   * @return the active workbench shell.
   */
  public static Shell getActiveWorkbenchShell() {
    IWorkbenchWindow window = getActiveWorkbenchWindow();
    if (window == null) {
      IWorkbenchWindow[] windows = getDefault().getWorkbench().getWorkbenchWindows();
      if (windows.length > 0) {
        return windows[0].getShell();
      }
    } else {
      return window.getShell();
    }
    return null;
  }

  @Override
  public void start(BundleContext context_p) throws Exception {
    super.start(context_p);
    __plugin = this;
    EGFPDEPlugin.getDefault().addResourceFcoreListener(FcoreListener.INSTANCE);
  }

  @Override
  public void stop(BundleContext context_p) throws Exception {
    __plugin = null;
    if (EGFPDEPlugin.getDefault() != null)
      EGFPDEPlugin.getDefault().removeResourceFcoreListener(FcoreListener.INSTANCE);
    super.stop(context_p);
  }

}