| /* |
| * Copyright 2009 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 com.google.gwt.event.shared.UmbrellaException; |
| |
| import java.util.HashSet; |
| import java.util.Set; |
| |
| /** |
| * An exception that is thrown when the panel fails to attach or detach its |
| * children. |
| */ |
| public class AttachDetachException extends UmbrellaException { |
| |
| /** |
| * The singleton command used to attach widgets. |
| */ |
| static final AttachDetachException.Command attachCommand = new AttachDetachException.Command() { |
| public void execute(Widget w) { |
| w.onAttach(); |
| } |
| }; |
| |
| /** |
| * The singleton command used to detach widgets. |
| */ |
| static final AttachDetachException.Command detachCommand = new AttachDetachException.Command() { |
| public void execute(Widget w) { |
| w.onDetach(); |
| } |
| }; |
| |
| /** |
| * The command to execute when iterating through child widgets. |
| */ |
| public static interface Command { |
| void execute(Widget w); |
| } |
| |
| /** |
| * <p> |
| * Iterator through all child widgets, trying to perform the specified |
| * {@link Command} for each. All widgets will be visited even if the Command |
| * throws an exception. If one or more exceptions occur, they will be combined |
| * and thrown as a single {@link AttachDetachException}. |
| * </p> |
| * <p> |
| * Use this method when attaching or detaching a widget with children to |
| * ensure that the logical and physical state of all children match the |
| * logical and physical state of the parent. |
| * </p> |
| * |
| * @param hasWidgets children to iterate |
| * @param c the {@link Command} to try on all children |
| */ |
| public static void tryCommand(Iterable<Widget> hasWidgets, Command c) { |
| Set<Throwable> caught = null; |
| for (Widget w : hasWidgets) { |
| try { |
| c.execute(w); |
| } catch (Throwable e) { |
| // Catch all exceptions to prevent some children from being attached |
| // while others are not. |
| if (caught == null) { |
| caught = new HashSet<Throwable>(); |
| } |
| caught.add(e); |
| } |
| } |
| |
| // Throw the combined exceptions now that all children are attached. |
| if (caught != null) { |
| throw new AttachDetachException(caught); |
| } |
| } |
| |
| /** |
| * <p> |
| * Iterator through all child widgets, trying to perform the specified |
| * {@link Command} for each. All widgets will be visited even if the Command |
| * throws an exception. If one or more exceptions occur, they will be combined |
| * and thrown as a single {@link AttachDetachException}. |
| * </p> |
| * <p> |
| * Use this method when attaching or detaching a widget with children to |
| * ensure that the logical and physical state of all children match the |
| * logical and physical state of the parent. |
| * </p> |
| * |
| * @param c the {@link Command} to try on all children |
| * @param widgets children to iterate, null children are ignored |
| */ |
| public static void tryCommand(Command c, IsWidget... widgets) { |
| Set<Throwable> caught = null; |
| for (IsWidget w : widgets) { |
| try { |
| if (w != null) { |
| c.execute(w.asWidget()); |
| } |
| } catch (Throwable e) { |
| // Catch all exceptions to prevent some children from being attached |
| // while others are not. |
| if (caught == null) { |
| caught = new HashSet<Throwable>(); |
| } |
| caught.add(e); |
| } |
| } |
| |
| // Throw the combined exceptions now that all children are attached. |
| if (caught != null) { |
| throw new AttachDetachException(caught); |
| } |
| } |
| |
| /** |
| * Construct a new {@link AttachDetachException}. |
| * |
| * @param causes the causes of the exception |
| */ |
| public AttachDetachException(Set<Throwable> causes) { |
| super(causes); |
| } |
| } |