com.google.gwt.user.cellview.client.CellBasedWidgetImpl Maven / Gradle / Ivy
/*
* Copyright 2010 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.cellview.client;
import com.google.gwt.core.client.GWT;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.client.Element;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.ui.Widget;
import java.util.HashSet;
import java.util.Locale;
import java.util.Set;
/**
* Implementation used by various cell based widgets.
*/
abstract class CellBasedWidgetImpl {
/**
* The singleton impl instance.
*/
private static CellBasedWidgetImpl impl;
/**
* Get the singleton instance.
*
* @return the {@link CellBasedWidgetImpl} instance
*/
public static CellBasedWidgetImpl get() {
if (impl == null) {
impl = GWT.create(CellBasedWidgetImpl.class);
}
return impl;
}
/**
* The set of natively focusable elements.
*/
final Set focusableTypes;
CellBasedWidgetImpl() {
focusableTypes = new HashSet();
focusableTypes.add("select");
focusableTypes.add("input");
focusableTypes.add("textarea");
focusableTypes.add("option");
focusableTypes.add("button");
focusableTypes.add("label");
}
/**
* Check if an element is focusable. If an element is focusable, the cell
* widget should not steal focus from it.
*
* @param elem the element
* @return true if the element is focusable, false if not
*/
public boolean isFocusable(Element elem) {
return focusableTypes.contains(elem.getTagName().toLowerCase(Locale.ROOT))
|| elem.getTabIndex() >= 0;
}
/**
* Process an event on a target cell.
*
* @param widget the {@link Widget} on which the event occurred
* @param event the event to handle
*/
public void onBrowserEvent(Widget widget, Event event) {
}
/**
* Takes in an html string and processes it, adding support for events.
*
* @param html the html string to process
* @return the processed html string
*/
public SafeHtml processHtml(SafeHtml html) {
return html;
}
/**
* Reset focus on an element.
*
* @param command the command to execute when resetting focus
*/
public void resetFocus(ScheduledCommand command) {
command.execute();
}
/**
* Sink events on the widget.
*
* @param widget the {@link Widget} that will handle the events
* @param typeNames the names of the events to sink
*/
public final void sinkEvents(Widget widget, Set typeNames) {
if (typeNames == null) {
return;
}
int eventsToSink = 0;
for (String typeName : typeNames) {
int typeInt = Event.getTypeInt(typeName);
if (typeInt < 0) {
widget.sinkBitlessEvent(typeName);
} else {
typeInt = sinkEvent(widget, typeName);
if (typeInt > 0) {
eventsToSink |= typeInt;
}
}
}
if (eventsToSink > 0) {
widget.sinkEvents(eventsToSink);
}
}
/**
* Get the event bits to sink for an event type.
*
* @param widget the {@link Widget} that will handle the events
* @param typeName the name of the event to sink
* @return the event bits to sink, or -1 if no events to sink
*/
protected int sinkEvent(Widget widget, String typeName) {
return Event.getTypeInt(typeName);
}
}