/*
* 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.JavaScriptObject;
import com.google.gwt.core.client.Scheduler;
import com.google.gwt.core.client.Scheduler.ScheduledCommand;
import com.google.gwt.dom.client.BrowserEvents;
import com.google.gwt.dom.client.Document;
import com.google.gwt.dom.client.Element;
import com.google.gwt.dom.client.EventTarget;
import com.google.gwt.dom.client.InputElement;
import com.google.gwt.safehtml.shared.SafeHtml;
import com.google.gwt.safehtml.shared.SafeHtmlUtils;
import com.google.gwt.user.client.DOM;
import com.google.gwt.user.client.Event;
import com.google.gwt.user.client.EventListener;
import com.google.gwt.user.client.ui.Widget;
import java.util.HashSet;
import java.util.Set;
/**
* IE specified Impl used by cell based widgets.
*/
class CellBasedWidgetImplTrident extends CellBasedWidgetImpl {
/**
* The method used to dispatch non-bubbling events.
*/
private static JavaScriptObject dispatchFocusEvent;
/**
* The currently focused input element, select box, or text area.
*/
private static Element focusedInput;
/**
* If true, only synthesize change events when the focused input is blurred.
*/
private static boolean focusedInputChangesOnBlurOnly;
/**
* The last value of the focused input element.
*/
private static Object focusedInputValue;
/**
* The set of input types that can receive change events.
*/
private static Set<String> inputTypes;
/**
* Dispatch an event to the cell, ensuring that the widget will catch it.
*
* @param widget the widget that will handle the event
* @param target the cell element
* @param eventBits the event bits to sink
* @param event the event to fire, or null not to fire an event
*/
private static void dispatchCellEvent(Widget widget,
com.google.gwt.user.client.Element target, int eventBits, Event event) {
// Make sure that the target is still a child of the widget. We defer the
// firing of some events, so its possible that the DOM structure has
// changed before we fire the event.
if (!widget.getElement().isOrHasChild(target)) {
return;
}
// Temporary listen for events from the cell. The event listener will be
// removed in onBrowserEvent().
DOM.setEventListener(target, widget);
DOM.sinkEvents(target, eventBits | DOM.getEventsSunk(target));
// Dispatch the event to the cell.
if (event != null) {
target.dispatchEvent(event);
}
}
/**
* Dispatch an event through the normal GWT mechanism.
*/
private static native void dispatchEvent(Event evt, Element elem,
EventListener listener) /*-{
@com.google.gwt.user.client.DOM::dispatchEvent(Lcom/google/gwt/user/client/Event;Lcom/google/gwt/user/client/Element;Lcom/google/gwt/user/client/EventListener;)(evt, elem, listener);
}-*/;
/**
* Get the value of an element that has a value or checked state.
*
* @param elem the input element
* @return the value of the input
*/
private static Object getInputValue(Element elem) {
if (isCheckbox(elem)) {
return InputElement.as(elem).isChecked();
}
return getInputValueImpl(elem);
}
/**
* Get the value of an element that has a value, such as an input element,
* textarea, or select box.
*
* @param elem the input element
* @return the value of the input
*/
private static native String getInputValueImpl(Element elem) /*-{
return elem.value;
}-*/;
/**
* Used by {@link #initFocusEventSystem()} and {@link #initLoadEvents(String)}
* to handle non bubbling events .
*
* @param event
*/
@SuppressWarnings("unused")
private static void handleNonBubblingEvent(Event event) {
// Get the event target.
EventTarget eventTarget = event.getEventTarget();
if (!Element.is(eventTarget)) {
return;
}
final com.google.gwt.user.client.Element target = eventTarget.cast();
// Get the event listener.
com.google.gwt.user.client.Element curElem = target;
EventListener listener = DOM.getEventListener(curElem);
while (curElem != null && listener == null) {
curElem = curElem.getParentElement().cast();
listener = (curElem == null) ? null : DOM.getEventListener(curElem);
}
// Get the Widget from the event listener.
if (!(listener instanceof Widget)) {
return;
}
Widget widget = (Widget) listener;
// Do not special case events that occur on the widget itself.
if (target == widget.getElement()) {
return;
}
String type = event.getType();
if (BrowserEvents.FOCUSIN.equals(type)) {
// If this is an input element, remember that we focused it.
String tagName = target.getTagName().toLowerCase();
if (inputTypes.contains(tagName)) {
focusedInput = target;
focusedInputValue = getInputValue(target);
focusedInputChangesOnBlurOnly = !"select".equals(tagName)
&& !isCheckbox(target);
}
// The focus event has not fired yet, so we just need to set the
// CellTable as the event listener and wait for it.
dispatchCellEvent(widget, target, Event.ONFOCUS, null);
} else if (BrowserEvents.FOCUSOUT.equals(type)) {
// Fire a change event on the input element if the value changed.
maybeFireChangeEvent(widget);
focusedInput = null;
// The blur event has already fired, so we need to synthesize one.
Event blurEvent = Document.get().createFocusEvent().cast();
dispatchCellEvent(widget, target, Event.ONBLUR, null);
} else if (BrowserEvents.LOAD.equals(type) || BrowserEvents.ERROR.equals(type)) {
dispatchEvent(event, widget.getElement(), listener);
}
}
/**
* Check whether or not an element is a checkbox or radio button.
*
* @param elem the element to check
* @return true if a checkbox, false if not
*/
private static boolean isCheckbox(Element elem) {
if (elem == null || !"input".equalsIgnoreCase(elem.getTagName())) {
return false;
}
String inputType = InputElement.as(elem).getType().toLowerCase();
return "checkbox".equals(inputType) || "radio".equals(inputType);
}
/**
* Synthesize a change event on the focused input element if the value has
* changed.
*
* @param widget the {@link Widget} containing the element
*/
private static void maybeFireChangeEvent(Widget widget) {
if (focusedInput == null) {
return;
}
Object newValue = getInputValue(focusedInput);
if (!newValue.equals(focusedInputValue)) {
// Save the new value in case it changes again.
focusedInputValue = newValue;
// Fire a synthetic event to the input element.
com.google.gwt.user.client.Element target = focusedInput.cast();
Event changeEvent = Document.get().createChangeEvent().cast();
dispatchCellEvent(widget, target, Event.ONCHANGE, changeEvent);
}
}
/**
* The set of event types that can trigger a change event.
*/
private final Set<String> changeEventTriggers;
/**
* If true, load events have been initialized.
*/
private boolean loadEventsInitialized;
public CellBasedWidgetImplTrident() {
// Initialize the input types.
if (inputTypes == null) {
inputTypes = new HashSet<String>();
inputTypes.add("select");
inputTypes.add("input");
inputTypes.add("textarea");
}
// Initialize the change event triggers.
changeEventTriggers = new HashSet<String>();
changeEventTriggers.add(BrowserEvents.MOUSEUP);
changeEventTriggers.add(BrowserEvents.MOUSEWHEEL);
}
@Override
public boolean isFocusable(Element elem) {
return focusableTypes.contains(elem.getTagName().toLowerCase())
|| getTabIndexIfSpecified(elem) >= 0;
}
@Override
public void onBrowserEvent(final Widget widget, Event event) {
// We need to remove the event listener from the cell now that the event
// has fired.
String type = event.getType().toLowerCase();
if (BrowserEvents.FOCUS.equals(type) || BrowserEvents.BLUR.equals(type) || BrowserEvents.CHANGE.equals(type)) {
EventTarget eventTarget = event.getEventTarget();
if (Element.is(eventTarget)) {
com.google.gwt.user.client.Element target = eventTarget.cast();
if (target != widget.getElement()) {
DOM.setEventListener(target, null);
}
}
}
// Update the value of the focused input box.
if (focusedInput != null && BrowserEvents.CHANGE.equals(type)) {
focusedInputValue = getInputValue(focusedInput);
}
// We might need to fire a synthetic change event on the input element.
if (focusedInput != null && !focusedInputChangesOnBlurOnly
&& changeEventTriggers.contains(type)) {
// Defer the change event because the change does not occur until after
// the events specified above.
Scheduler.get().scheduleDeferred(new ScheduledCommand() {
public void execute() {
maybeFireChangeEvent(widget);
}
});
}
}
@Override
public SafeHtml processHtml(SafeHtml html) {
// If the widget is listening for load events, we modify the HTML to add the
// load/error listeners.
if (loadEventsInitialized && html != null) {
String moduleName = GWT.getModuleName();
String listener = "__gwt_CellBasedWidgetImplLoadListeners[\""
+ moduleName + "\"]();";
String htmlString = html.asString();
htmlString = htmlString.replaceAll("(<img)([\\s/>])", "<img onload='"
+ listener + "' onerror='" + listener + "'$2");
// We assert that the resulting string is safe
html = SafeHtmlUtils.fromTrustedString(htmlString);
}
return html;
}
@Override
public void resetFocus(ScheduledCommand command) {
// IE will not focus an element that was created in this event loop.
Scheduler.get().scheduleDeferred(command);
}
@Override
protected int sinkEvent(Widget widget, String typeName) {
if (BrowserEvents.CHANGE.equals(typeName) || BrowserEvents.FOCUS.equals(typeName)
|| BrowserEvents.BLUR.equals(typeName)) {
// Initialize the focus events.
if (dispatchFocusEvent == null) {
initFocusEventSystem();
}
// Sink the events required for focus. We use an attribute on the widget
// to remember whether or not we've sunk the events.
int eventsToSink = 0;
Element elem = widget.getElement();
String attr = "__gwtCellBasedWidgetImplDispatchingFocus";
if (!"true".equals(elem.getAttribute(attr))) {
elem.setAttribute(attr, "true");
sinkFocusEvents(elem);
// Sink the events that could trigger a change event. Change events
// are also triggered on blur if the value changes.
for (String trigger : changeEventTriggers) {
eventsToSink |= Event.getTypeInt(trigger);
}
}
return eventsToSink;
} else if (BrowserEvents.LOAD.equals(typeName) || BrowserEvents.ERROR.equals(typeName)) {
// Initialize the load listener.
if (!loadEventsInitialized) {
loadEventsInitialized = true;
initLoadEvents(GWT.getModuleName());
}
return -1;
} else {
return super.sinkEvent(widget, typeName);
}
}
/**
* Get the tab index of an element if the tab index is specified.
*
* @param elem the Element
* @return the tab index, or -1 if not specified
*/
private native int getTabIndexIfSpecified(Element elem) /*-{
var attrNode = elem.getAttributeNode('tabIndex');
return (attrNode != null && attrNode.specified) ? elem.tabIndex : -1;
}-*/;
/**
* Initialize the focus event listener.
*/
private native void initFocusEventSystem() /*-{
@com.google.gwt.user.cellview.client.CellBasedWidgetImplTrident::dispatchFocusEvent = $entry(function() {
@com.google.gwt.user.cellview.client.CellBasedWidgetImplTrident::handleNonBubblingEvent(Lcom/google/gwt/user/client/Event;)($wnd.event);
});
}-*/;
/**
* Initialize load events. We hang a method off of $wnd so we can reference it
* in the HTML generated for img tags.
*
* @param moduleName the module name of the current module
*/
private native void initLoadEvents(String moduleName) /*-{
// Initialize an array of listeners. Each module gets its own entry in the
// array to prevent conflicts on pages with multiple modules.
if (!$wnd.__gwt_CellBasedWidgetImplLoadListeners) {
$wnd.__gwt_CellBasedWidgetImplLoadListeners = new Array();
}
// Add an entry for the specified module.
$wnd.__gwt_CellBasedWidgetImplLoadListeners[moduleName] = $entry(function() {
@com.google.gwt.user.cellview.client.CellBasedWidgetImplTrident::handleNonBubblingEvent(Lcom/google/gwt/user/client/Event;)($wnd.event);
});
}-*/;
/**
* Sink focus events for the specified element.
*
* @param elem the element that will receive the events
*/
private native void sinkFocusEvents(Element elem) /*-{
elem.attachEvent('onfocusin',
@com.google.gwt.user.cellview.client.CellBasedWidgetImplTrident::dispatchFocusEvent);
elem.attachEvent('onfocusout',
@com.google.gwt.user.cellview.client.CellBasedWidgetImplTrident::dispatchFocusEvent);
}-*/;
}