| /* |
| * Copyright 2007 Google Inc. |
| * |
| * 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.google.gwt.user.client.ui; |
| |
| import java.util.Iterator; |
| import java.util.NoSuchElementException; |
| |
| /** |
| * A collection of convenience factories for creating iterators for widgets. |
| * This mostly helps developers support {@link HasWidgets} without having to |
| * implement their own {@link Iterator}. |
| */ |
| class WidgetIterators { |
| |
| private static Widget[] copyWidgetArray(final Widget[] widgets) { |
| final Widget[] clone = new Widget[widgets.length]; |
| for (int i = 0; i < widgets.length; i++) { |
| clone[i] = widgets[i]; |
| } |
| return clone; |
| } |
| |
| /** |
| * Wraps an array of widgets to be returned during iteration. |
| * <code>null</code> is allowed in the array and will be skipped during |
| * iteration. |
| * |
| * @param container the container of the widgets in <code>contained</code> |
| * @param contained the array of widgets |
| * @return the iterator |
| */ |
| static final Iterator<Widget> createWidgetIterator(final HasWidgets container, |
| final Widget[] contained) { |
| return new Iterator<Widget>() { |
| int index = -1, last = -1; |
| boolean widgetsWasCopied = false; |
| Widget[] widgets = contained; |
| |
| { |
| gotoNextIndex(); |
| } |
| |
| private void gotoNextIndex() { |
| ++index; |
| while (index < contained.length) { |
| if (contained[index] != null) { |
| return; |
| } |
| ++index; |
| } |
| } |
| |
| public boolean hasNext() { |
| return (index < contained.length); |
| } |
| |
| public Widget next() { |
| if (!hasNext()) { |
| throw new NoSuchElementException(); |
| } |
| last = index; |
| final Widget w = contained[index]; |
| gotoNextIndex(); |
| return w; |
| } |
| |
| public void remove() { |
| if (last < 0) { |
| throw new IllegalStateException(); |
| } |
| |
| if (!widgetsWasCopied) { |
| widgets = copyWidgetArray(widgets); |
| widgetsWasCopied = true; |
| } |
| |
| container.remove(contained[last]); |
| last = -1; |
| } |
| }; |
| } |
| |
| private WidgetIterators() { |
| // Not instantiable. |
| } |
| } |