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script value (ScriptEngine)

Posted on 2009-07-01
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Last Modified: 2012-05-07
I try to get some information in my script from my java program by using ScriptEngineManager.  Why values of the variables I would love to get were null?  How can I get a variable's value from the script?
My script...

function googleMapCal(lat, lng, city, region, country)

{

	var ClientLoc = google.loader.ClientLocation;

	drawMap(ClientLoc);

	lat = ClientLoc.latitude;

	lng = ClientLoc.Longitude;

	city = ClientLoc.address.city;

	region = ClientLoc.address.region;

	country = ClientLoc.address.country;

}
 

function drawMap(ClientLoc) {

    if (google.loader.ClientLocation) {

        var cl = google.loader.ClientLocation;

        var location = [cl.address.city, cl.address.region, cl.address.country].join(', ');

        ClientLoc = cl;

    } else {

        document.getElementById('cantfindyou').innerHTML = "Crap, I don't know. Good hiding!";

    }

}
 

Where I try to get values....

		ScriptEngineManager manager = new ScriptEngineManager();

		ScriptEngine engine = manager.getEngineByName("JavaScript");

		Bindings vars = new SimpleBindings();
 

		// Run Javascript

		try{

			engine.eval("function googleMapCal(lat, lng, city, region, country)" +

			"{" +

				"var ClientLoc = google.loader.ClientLocation;" +

				"drawMap(ClientLoc);" +

				"lat = ClientLoc.latitude;" +

				"lng = ClientLoc.Longitude;" +

				"city = ClientLoc.address.city;" +

				"region = ClientLoc.address.region;" +

				"country = ClientLoc.address.country;" +

			"}", vars);

		} catch (ScriptException ex){

			ex.printStackTrace();

		}

		

		// Get JavaScript Variables

		lat = (String)vars.get("lat");

		lng = (String)vars.get("lng");

		city = (String)vars.get("city");

		country = (String)vars.get("country");

		region = (String)vars.get("region");

		System.out.println("You are from " + lat + "/" + lng + "/" + city + "/" + country + "/" + region);

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Question by:xenia27
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6 Comments
 

Author Comment

by:xenia27
Comment Utility
What's wrong with my code?
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Accepted Solution

by:
mahome earned 500 total points
Comment Utility
You're just defining a function. You must call the function, that the values will be set. Here an example:

Bindings vars = new SimpleBindings();

                

        // Run Javascript

        try{

                engine.eval("function mytest(param1)" +

                "{" +

                        "value = param1;" +

                "}" +

                "mytest('test it');"

                        

                        , vars);

        } catch (ScriptException ex){

                ex.printStackTrace();

        }

        

        // Get JavaScript Variables

        String value = vars.get("value").toString();

        System.out.println("My Value: " + value);

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Author Comment

by:xenia27
Comment Utility
I got an error message "Source  not found"...
What should I do?  Did I define something wrong?
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Expert Comment

by:mahome
Comment Utility
Can you post your complete Java-main-Funktion and the complete error message.
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Author Comment

by:xenia27
Comment Utility
When I tried to run in debug mode, I got an error message pops up said I missed ";" somewhere in my file.  Then, I tried to run the function where calls javascript function and I got..

2009/7/2
H 08:12:23 com.google.appengine.tools.development.ApiProxyLocalImpl log
SEVERE: [1246522343671000] javax.servlet.ServletContext log: Exception while dispatching incoming RPC call
com.google.gwt.user.server.rpc.UnexpectedException: Service method 'public abstract java.lang.String com.unet.googleproject.client.GreetingService.greetServer(java.lang.String)' threw an unexpected exception: java.lang.NullPointerException
      at com.google.gwt.user.server.rpc.RPC.encodeResponseForFailure(RPC.java:360)
      at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:546)
      at com.google.gwt.user.server.rpc.RemoteServiceServlet.processCall(RemoteServiceServlet.java:166)
      at com.google.gwt.user.server.rpc.RemoteServiceServlet.doPost(RemoteServiceServlet.java:86)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:713)
      at javax.servlet.http.HttpServlet.service(HttpServlet.java:806)
      at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:487)
      at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1093)
      at com.google.apphosting.utils.servlet.TransactionCleanupFilter.doFilter(TransactionCleanupFilter.java:43)
      at org.mortbay.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1084)
      at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:360)
      at org.mortbay.jetty.security.SecurityHandler.handle(SecurityHandler.java:216)
      at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:181)
      at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:712)
      at org.mortbay.jetty.webapp.WebAppContext.handle(WebAppContext.java:405)
      at com.google.apphosting.utils.jetty.DevAppEngineWebAppContext.handle(DevAppEngineWebAppContext.java:54)
      at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
      at com.google.appengine.tools.development.JettyContainerService$ApiProxyHandler.handle(JettyContainerService.java:306)
      at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:139)
      at org.mortbay.jetty.Server.handle(Server.java:313)
      at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:506)
      at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:844)
      at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:644)
      at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:205)
      at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:381)
      at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:396)
      at org.mortbay.thread.BoundedThreadPool$PoolThread.run(BoundedThreadPool.java:442)
Caused by: java.lang.NullPointerException
      at com.unet.googleproject.server.GreetingServiceImpl.GetClient(GreetingServiceImpl.java:48)
      at com.unet.googleproject.server.GreetingServiceImpl.greetServer(GreetingServiceImpl.java:28)
      at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
      at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
      at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
      at java.lang.reflect.Method.invoke(Unknown Source)
      at com.google.gwt.user.server.rpc.RPC.invokeAndEncodeResponse(RPC.java:527)
      ... 25 more
this is where I try to call the javascript function...

public class GreetingServiceImpl extends RemoteServiceServlet implements

		GreetingService {
 

	public String greetServer(String input) {

		

		String serverInfo = getServletContext().getServerInfo();

		String userAgent = getThreadLocalRequest().getHeader("User-Agent");

		Locale clientRequest = getThreadLocalRequest().getLocale();

		String clientHostAddr = getThreadLocalRequest().getRemoteAddr();

		String lat = new String();

		String lng = new String();

		String city = new String();

		String country = new String();

		String region = new String();

		

		GetClient(lat, lng, city, country, region);

		

		return "Hello, " + input + "!<br><br>I am running " + serverInfo

				+ ".<br><br>It looks like you are using:<br>" + userAgent

				+ ".<br><br>You are from:<br>" + city + "/" + country + " " + region

				+ ".<br><br>Your Lat/Lng:<br>" + lat + "/" + lng;

	}

	

	public void GetClient(String lat, String lng, String city, String country, String region)

	{

		ScriptEngineManager manager = new ScriptEngineManager();

		ScriptEngine engine = manager.getEngineByName("javascript");

		Bindings vars = new SimpleBindings();

		Invocable invocableEngine = (Invocable)engine; 
 

		// Run Javascript

		try{

			engine.eval("function getInfo(Lat){"

					+ "  getLat(Lat); } ", vars

        		);

			lat = vars.get("Lat").toString();

			System.out.println("Lat: " + lat);

		} catch (ScriptException ex){

			ex.printStackTrace();

		} 
 

	}

}
 

this is where I have my javascript...in a html file...

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"

        "http://www.w3.org/TR/html4/loose.dtd">

<!-- The HTML 4.01 Transitional DOCTYPE declaration-->

<!-- above set at the top of the file will set     -->

<!-- the browser's rendering engine into           -->

<!-- "Quirks Mode". Replacing this declaration     -->

<!-- with a "Standards Mode" doctype is supported, -->

<!-- but may lead to some differences in layout.   -->
 

<html>

  <head>

    <meta http-equiv="content-type" content="text/html; charset=UTF-8">
 

    <!--                                                               -->

    <!-- Consider inlining CSS to reduce the number of requested files -->

    <!--                                                               -->

    <link type="text/css" rel="stylesheet" href="xxx.css">
 

    <!--                                           -->

    <!-- Any title is fine                         -->

    <!--                                           -->

    <title>Web Application Starter Project</title>

    

    <!--                                           -->

    <!-- This script loads your compiled module.   -->

    <!-- If you add any GWT meta tags, they must   -->

    <!-- be added before this line.                -->

    <!--                                           -->

    <script type="text/javascript" language="javascript" src="xxx/xxxt.nocache.js"></script>

      <style type="text/css">

  body {

    padding: 0;

    margin: 0;

    background-color: #4f4e45;

    font-family: Tahoma, Arial, sans-serif;

  }

  

  #header {

    height: 30px;

    background-color: #111;

    color: #EEE;

    font-size: 10pt;

    padding-top: 4px;

    border-bottom: 1px solid #333;

  }

  

  #main {

    margin: 20px auto;  

    width: 610px;

  }

  

  #main h2 {

    font-weight: normal;

    margin: 0;

    color: #ff9600;

    font-size: 16pt;

    font-family: Tahoma, Arial, sans-serif;

    padding-bottom: 1em;

  }

  

  a {

    color: #fff;

  }
 

  #cantfindyou {

      font-size: 18pt;

  }

  

  #map {

      display: none;

      height: 300px;

      border: 1px solid black;

      margin: 10px 4px;

  }

  </style>

    

  </head>
 

  <!--                                           -->

  <!-- The body can have arbitrary html, or      -->

  <!-- you can leave the body empty if you want  -->

  <!-- to create a completely dynamic UI.        -->

  <!--                                           -->

<body>
 

    <!-- OPTIONAL: include this if you want history support -->

    <iframe src="javascript:''" id="__gwt_historyFrame" tabIndex='-1' style="position:absolute;width:0;height:0;border:0"></iframe>
 

    <h1>Web Application Starter Project</h1>
 

    <table align="center">

      <tr>

        <td colspan="2" style="font-weight:bold;">Please enter your name:</td>        

      </tr>

      <tr>

        <td id="nameFieldContainer"></td>

        <td id="sendButtonContainer"></td>

      </tr>

    </table>

    

	<script type="text/javascript" src="http://www.google.com/jsapi?key=ABQIAAAAJjoQAkGmq5qsa0PKk9Y6nxQdF2TG78juI7gyCxAZXlcasg4lQxTlaYHDB6IKUESWIPTqiJvXPeiwhg"></script>

	<script type="text/javascript">
 

	functionn getInfo(Lat)

	{

		getLat(Lat);

	}
 

	function getLat(Lat)

	{

	    if (google.loader.ClientLocation) {

	        var cl = google.loader.ClientLocation;

	        var location = [cl.address.city, cl.address.region, cl.address.country].join(', ');

	    }

	    Lat = cl.latitude;

	}
 

	</script>
 

</body>
 

</html>

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Author Comment

by:xenia27
Comment Utility
Any help?
Is there any example which contains both javascript and java examples?  All I can find is examples in java about how I can use ScriptEngineManager.

By the way, I try to create a web application with google wizard and eclipse.  Please help me~
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