Rhino : JavaScript Library for Java

• Rhino is a java library for java script native object and script handling for java developer.
• In java version 6 is embedded implicitly as a default script engine. For java version less then 6 must download the rhino library from the following download location :-

          https://developer.mozilla.org/en-US/docs/Rhino/Download_Rhino?redirectlocale=en-US&redirectslug=RhinoDownload

Project Structure:-

Rhino Script Object & Context:-

• org.mozilla.javascript.Context is the class for entering the script context . It generally used for saving call stack.It is necessary to create a context for executing script.

RhinoJavaScriptDemo.java ,

package com.sandeep.rhino.js;

import org.mozilla.javascript.Context;
import org.mozilla.javascript.Script;
import org.mozilla.javascript.Scriptable;

public class RhinoJavaScriptDemo {

 
 public static void main(String[] args) {

  Context mozillaJsContext = Context.enter();
  Scriptable scope = mozillaJsContext.initStandardObjects();
  
  /*A Javascript JSON Object*/
  String source = "{a :{5+6}}";
  Script scriptjs = mozillaJsContext.compileString(source, "sandeepDemoScript", 1, null);
  
  /*Result is a Javascript Object*/
  Object jsObjectResult = scriptjs.exec(mozillaJsContext, scope);
  String result = Context.toString(jsObjectResult);
  System.out.println("After Evaluating JS Object value is: "+result);
 }

}

Output:-

After Evaluating JS Object value is: 11

Rhino Script Engine and External Script File:-

• javax.script.ScriptEngine & javax.script.ScriptEngineManager are two classes to execute and manage script.
• Let the external java script file is demoJavaScriptFile.js .

demoJavaScriptFile.js , 

function add(num1,num2){
  var sum = num1+num2;
  print('Sum of the parameters passed By Java : '+sum);
 
 }

JavaScriptEngineDemo.java , 

package com.sandeep.rhino.js;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.Reader;
import javax.script.Invocable;
import javax.script.ScriptEngine;
import javax.script.ScriptEngineManager;
import javax.script.ScriptException;

public class JavaScriptEngineDemo {

 
 public static void main(String[] args) throws FileNotFoundException, ScriptException, NoSuchMethodException {

  File jsFile = new File("./demoJavaScriptFile.js");
  ScriptEngineManager factory = new ScriptEngineManager();
  ScriptEngine jsEngine = factory.getEngineByName("javascript");
  jsEngine.put("out", System.out);
  Reader reader = new FileReader(jsFile);
  jsEngine.eval(reader);
  Invocable invocableEngine = (Invocable) jsEngine;
   
        
  invocableEngine.invokeFunction("add",5,6);

 }

}

Output :-

Sum of the parameters passed By Java : 11

Code Download:-

    Rhino demo code download link