All Downloads are FREE. Search and download functionalities are using the official Maven repository.

com.google.gwt.core.client.JavaScriptObject Maven / Gradle / Ivy

There is a newer version: 2.7.0.vaadin7
Show newest version
/*
 * 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.core.client;

import com.google.gwt.core.client.impl.Impl;

/**
 * An opaque handle to a native JavaScript object. A
 * JavaScriptObject cannot be created directly.
 * JavaScriptObject should be declared as the return type of a
 * JSNI method that returns native (non-Java) objects. A
 * JavaScriptObject passed back into JSNI from Java becomes the
 * original object, and can be accessed in JavaScript as expected.
 */
public class JavaScriptObject {

  /**
   * Returns a new array.
   */
  public static native JavaScriptObject createArray() /*-{
    return [];
  }-*/;

  /**
   * Returns a new array with a given size.
   *
   * 

Consider using this method in performance critical code instead of using * {@link #createArray()}, since this gives more hints to the underlying * JavaScript VM for optimizations. */ public static native JavaScriptObject createArray(int size) /*-{ return new Array(size); }-*/; /** * Returns an empty function. */ public static native JavaScriptObject createFunction() /*-{ return function() { }; }-*/; /** * Returns a new object. */ public static native JavaScriptObject createObject() /*-{ return {}; }-*/; /** * Helper for {@link #toString()}, for lighter "more production" code. */ private static native String toStringSimple(JavaScriptObject obj) /*-{ return obj.toString ? obj.toString() : '[JavaScriptObject]'; }-*/; /** * Helper for {@link #toString()}, when Development Mode or assertions are on. */ private static native String toStringVerbose(JavaScriptObject obj) /*-{ var defined = function(m) { return typeof m != 'undefined'; }; var strip = function(s) { return s.replace(/\r\n/g, ""); }; // Output nodes that have outerHTML if (defined(obj.outerHTML)) return strip(obj.outerHTML); // Output nodes that have innerHTML if (defined(obj.innerHTML) && obj.cloneNode) { $doc.createElement('div').appendChild(obj.cloneNode(true)).innerHTML; } // Output text nodes if (defined(obj.nodeType) && obj.nodeType == 3) { return "'" + obj.data.replace(/ /g, "\u25ab").replace(/\u00A0/, "\u25aa") + "'"; } // Output IE's TextRange (this code specific to IE7) if (typeof defined(obj.htmlText) && obj.collapse) { var html = obj.htmlText; if (html) { return 'IETextRange [' + strip(html) + ']'; } else { // NOTE: using pasteHTML to place a | where the range is collapsed // if *very* useful when debugging. It also, however, in certain very // subtle circumstances change the range being toStringed! If you // see different behaviour in debug vs. release builds (or if logging // ranges changes the behaviour, comment out the 4 of the 6 lines // below containing dup. var dup = obj.duplicate(); dup.pasteHTML('|'); var out = 'IETextRange ' + strip(obj.parentElement().outerHTML); dup.moveStart('character', -1); dup.pasteHTML(''); return out; } } return obj.toString ? obj.toString() : '[JavaScriptObject]'; }-*/; /** * Not directly instantiable. All subclasses must also define a protected, * empty, no-arg constructor. */ protected JavaScriptObject() { } /** * A helper method to enable cross-casting from any {@link JavaScriptObject} * type to any other {@link JavaScriptObject} type. * * @param the target type * @return this object as a different type */ @SuppressWarnings("unchecked") public final T cast() { return (T) this; } /** * Returns true if the objects are JavaScript identical * (triple-equals). */ @Override public final boolean equals(Object other) { return super.equals(other); } /** * Uses a monotonically increasing counter to assign a hash code to the * underlying JavaScript object. Do not call this method on non-modifiable * JavaScript objects. * * TODO: if the underlying object defines a 'hashCode' method maybe use that? * * @return the hash code of the object */ @Override public final int hashCode() { return Impl.getHashCode(this); } /** * Call the toSource() on the JSO. */ public native String toSource() /*-{ this.toSource ? this.toSource() : "NO SOURCE"; }-*/; /** * Makes a best-effort attempt to get a useful debugging string describing the * given JavaScriptObject. In Production Mode with assertions disabled, this * will either call and return the JSO's toString() if one exists, or just * return "[JavaScriptObject]". In Development Mode, or with assertions * enabled, some stronger effort is made to represent other types of JSOs, * including inspecting for document nodes' outerHTML and innerHTML, etc. */ @Override public final String toString() { return JavaScriptObject.class.desiredAssertionStatus() ? toStringVerbose(this) : toStringSimple(this); } }





© 2015 - 2024 Weber Informatics LLC | Privacy Policy