private ISiteFeature[] getFeaturesFromSelection(IStructuredSelection sel) {
   if (sel.isEmpty()) return new ISiteFeature[0];
   if (cachedSelection == sel) return cachedFeatures;
   cachedSelection = sel;
   ArrayList<ISiteFeature> features = new ArrayList<ISiteFeature>(sel.size());
   Iterator<?> iterator = sel.iterator();
   while (iterator.hasNext()) {
     Object next = iterator.next();
     if (next instanceof SiteFeatureAdapter) {
       if ((((SiteFeatureAdapter) next).feature) != null) {
         features.add(((SiteFeatureAdapter) next).feature);
       }
     }
   }
   cachedFeatures = features.toArray(new ISiteFeature[features.size()]);
   return cachedFeatures;
 }
  private boolean handleRemove() {
    IStructuredSelection ssel = (IStructuredSelection) fCategoryViewer.getSelection();
    Iterator<?> iterator = ssel.iterator();
    boolean success = true;
    Set<?> removedCategories = new HashSet<Object>();
    while (iterator.hasNext()) {
      Object object = iterator.next();
      if (object == null) continue;
      if (object instanceof ISiteCategoryDefinition) {
        if (!handleRemoveCategoryDefinition((ISiteCategoryDefinition) object)) {
          success = false;
        }
      } else {
        // check if some of features was not removed during category removal
        SiteFeatureAdapter fa = (SiteFeatureAdapter) object;
        if (removedCategories.contains(fa.category)) continue;

        if (!handleRemoveSiteFeatureAdapter(fa)) {
          success = false;
        }
      }
    }
    return success;
  }
  public static void handleAddRequired(IProductPlugin[] plugins, boolean includeOptional) {
    if (plugins.length == 0) return;

    ArrayList<BundleDescription> list = new ArrayList<BundleDescription>(plugins.length);
    for (int i = 0; i < plugins.length; i++) {
      list.add(TargetPlatformHelper.getState().getBundle(plugins[i].getId(), null));
    }
    DependencyCalculator calculator = new DependencyCalculator(includeOptional);
    calculator.findDependencies(list.toArray());

    BundleDescription[] bundles = TargetPlatformHelper.getState().getBundles();
    for (int i = 0; i < bundles.length; i++) {
      HostSpecification host = bundles[i].getHost();
      if (host != null
          && !("org.eclipse.ui.workbench.compatibility"
              .equals(bundles[i].getSymbolicName())) // $NON-NLS-1$
          && calculator.containsPluginId(host.getName())) {
        calculator.findDependency(bundles[i]);
      }
    }

    Collection<?> dependencies = calculator.getBundleIDs();

    IProduct product = plugins[0].getProduct();
    IProductModelFactory factory = product.getModel().getFactory();
    IProductPlugin[] requiredPlugins = new IProductPlugin[dependencies.size()];
    int i = 0;
    Iterator<?> iter = dependencies.iterator();
    while (iter.hasNext()) {
      String id = iter.next().toString();
      IProductPlugin plugin = factory.createPlugin();
      plugin.setId(id);
      requiredPlugins[i++] = plugin;
    }
    product.addPlugins(requiredPlugins);
  }