com.google.gwt.user.client.ui.AttachDetachException Maven / Gradle / Ivy
/*
* 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);
}
/**
*
* 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}.
*
*
* 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.
*
*
* @param hasWidgets children to iterate
* @param c the {@link Command} to try on all children
*/
public static void tryCommand(Iterable hasWidgets, Command c) {
Set 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();
}
caught.add(e);
}
}
// Throw the combined exceptions now that all children are attached.
if (caught != null) {
throw new AttachDetachException(caught);
}
}
/**
*
* 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}.
*
*
* 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.
*
*
* @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 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();
}
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 causes) {
super(causes);
}
}