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The Google API Libraries for Google Web Toolkit is a collection of libraries that provide Java language bindings for popular Google JavaScript APIs. These libraries make it quick and easy for developers to use these Google JavaScript APIs with Google Web Toolkit. The libraries are supported by the Google Web Toolkit team.

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/*
 * 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.ajaxloader.client;

import com.google.gwt.core.client.JavaScriptObject;

import java.util.Date;

/**
 * Wraps a JavaScript Date object.
 */
public class JsDate extends JavaScriptObject {  
  /**
   * Create a JsDate with the current time.
   *
   * @return A JsDate with the current time.
   */
  public static native JsDate create() /*-{
    var result = new $wnd.Date();
    // Safari bug: see issue 219
    result.constructor = $wnd.Date;
    return result;
  }-*/;
  
  /**
   * Create a date given the time in milliseconds.
   * 
   * @param time A time value in milliseconds.  Uses the double type for 
   * efficiency.
   * @return A JsDate with the given time.
   */
  public static native JsDate create(double time) /*-{
    var result = new $wnd.Date(time);
    // Safari bug: see issue 219
    result.constructor = $wnd.Date;
    return result;
  }-*/;
  /**
   * Tests if the JavaScriptObject can be cast to JsDate.  Checks if the
   * underlying JavaScript object has a method called getTime() that returns
   * a number.
   * 
   * @param js A JavaScriptObject that may or may not be wrapping a JavaScript
   * Date object.
   * @return false if the JavaScriptObject is null or if it cannot be cast
   * to JsDate, otherwise true.
   */
  public static native boolean isDate(JavaScriptObject js) /*-{
    var result = false;
    if (js != null) {
      if (typeof js.getTime == 'function') {
        var time = js.getTime();
        if (typeof time == 'number') {
          result = true;
        }
      }
    }
    return result;
  }-*/;
  
  /**
   * Converts a JsDate to a Java Date.  If the JsDate is null, the function 
   * returns null.
   * 
   * @param js A JsDate.
   * @return A Java Date object, or null, if js is null.
   */
  public static Date toJava(JsDate js) {
    return js == null ? null : new Date(js.getTime());
  }
  
  /**
   * Converts a Java Date to a JsDate.  If the Date is null, the function 
   * returns null.
   * 
   * @param java A Java Date.
   * @return An analogous JsDate, or null if the original Java Date was null.
   */
  public static JsDate toJs(Date java) {
    return java == null ? null : create(java.getTime());
  }  
  
  protected JsDate() {
  }

  /**
   * A wrapper for the JavaScript Date's getTime() method.
   * 
   * @return The time in milliseconds corresponding to this JsDate.
   */
  public final long getTime() {
    return (long) doubleTime();
  }
  
  private native double doubleTime() /*-{
    return this.getTime();
  }-*/;
}