Java tutorial
/* * Copyright 2008 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.impl; import com.google.gwt.core.client.JavaScriptObject; import com.google.gwt.dom.client.Element; import com.google.gwt.dom.client.ElementRemote; import com.google.gwt.user.client.Event; import com.google.gwt.user.client.EventListener; /** * Native implementation associated with {@link com.google.gwt.user.client.DOM}. */ public abstract class DOMImpl { protected static boolean eventSystemIsInitialized; /* * the uiObjectListener is mostly to reduce calls to DOM - so if it was set * before toRemote, it'll never be set later */ public static EventListener getEventListener(Element elem) { if (elem.implAccess().linkedToRemote()) { EventListener eventListener = getEventListener0(elem.implAccess().typedRemote()); if (eventListener != null) { return eventListener; } } return elem.uiObjectListener; } public static void setEventListener(Element elem, EventListener listener) { ElementRemote remote = elem.implAccess().typedRemoteOrNull(); if (remote != null) { setEventListener0(remote, listener); } else { elem.uiObjectListener = listener; } } private static native EventListener getEventListener0(ElementRemote elem) /*-{ // Return elem.__listener if and only if it was assigned from our module var maybeListener = elem.__listener; return @com.google.gwt.user.client.impl.DOMImpl::isMyListener(*)(maybeListener) ? maybeListener : null; }-*/; /** * Returns <code>true</code>if the object is an instance of EventListener * and the object belongs to this module. * <p> * Note that this method should only be called from JSNI, otherwise it can * be inlined and compiler can remove instanceOf checks. E.g. * * <pre> * EventListener listener = getEventListenerFromSomeJsniCode(); * if (isMyListener(listener)) { * // This block will always be executed because the compiler proves * // that the instance of checks * // are not required after inlining isMyListener. * } * </pre> */ private static boolean isMyListener(Object object) { /* * The first test ensures the Object belongs to this module in * Production Mode by ensuring this is not a JavaScriptObject. In * Production Mode, foreign Java objects appear to be JavaScriptObject. * See Cast.isJavaScriptObject(). * * The second test then checks the exact type. * * TODO: make the generated code smaller! */ return !(object instanceof JavaScriptObject) && (object instanceof com.google.gwt.user.client.EventListener); } private static native void setEventListener0(ElementRemote elem, EventListener listener) /*-{ elem.__listener = listener; }-*/; public native void eventCancelBubble(Event evt, boolean cancel) /*-{ evt.cancelBubble = cancel; }-*/; public abstract Element eventGetFromElement(Event evt); public native boolean eventGetRepeat(Event evt) /*-{ return !!evt.repeat; }-*/; public abstract Element eventGetToElement(Event evt); public final int eventGetTypeInt(Event evt) { return eventGetTypeInt(evt.getType()); } public int eventGetTypeInt(String eventType) { switch (eventType) { case "blur": return 0x01000; case "change": return 0x00400; case "click": return 0x00001; case "dblclick": return 0x00002; case "focus": return 0x00800; case "keydown": return 0x00080; case "keypress": return 0x00100; case "keyup": return 0x00200; case "load": return 0x08000; case "losecapture": return 0x02000; case "mousedown": return 0x00004; case "mousemove": return 0x00040; case "mouseout": return 0x00020; case "mouseover": return 0x00010; case "mouseup": return 0x00008; case "scroll": return 0x04000; case "error": return 0x10000; case "mousewheel": return 0x20000; case "DOMMouseScroll": return 0x20000; case "contextmenu": return 0x40000; case "paste": return 0x80000; case "touchstart": return 0x100000; case "touchmove": return 0x200000; case "touchend": return 0x400000; case "touchcancel": return 0x800000; case "gesturestart": return 0x1000000; case "gesturechange": return 0x2000000; case "gestureend": return 0x4000000; default: return -1; } } public native void eventSetKeyCode(Event evt, char key) /*-{ evt.keyCode = key; }-*/; public abstract Element getChild(Element elem, int index); public abstract int getChildCount(Element elem); public abstract int getChildIndex(Element parent, Element child); public int getEventsSunk(Element elem) { if (elem.implAccess().linkedToRemote()) { ElementRemote remote = elem.implAccess().typedRemote(); return getEventsSunk0(remote); } else { return elem.localEventBitsSunk(); } } public abstract void insertChild(Element parent, Element child, int index); public void maybeInitializeEventSystem() { if (!eventSystemIsInitialized) { initEventSystem(); eventSystemIsInitialized = true; } } public abstract void releaseCapture(Element elem); public abstract void setCapture(Element elem); public abstract void sinkBitlessEvent(Element elem, String eventTypeName); public abstract void sinkEvents(Element elem, int eventBits); /** * Initializes the event dispatch system. */ protected abstract void initEventSystem(); native int getEventsSunk0(ElementRemote elem) /*-{ return elem.__eventBits || 0; }-*/; }