Loading data from a JavaScript file

Question

I am writing a Java application that will run client-side, and will essentially allow the user to download, update, and then reupload a JavaScript file. The data I'm needing to parse / build to the JS file consists of staticlly-defined string arrays, and one associative array.
The file looks like this.
var array1 = new Array();
array1[0] = "String1";
array1[1] = "String 2";
array1[2] = "String 3";I'm wondering if there is a more simple/eleoquent way of loading arrays from a JavaScript file than simply reading them and writing parse code by hand to extract the data I want... I can write the parsing code without any problem, but, I'm wondering if there's something built-in that I just don't know about...
Thanks

Answer 1

You can use the ScriptEngine provided in Java 6. Takes a little hacking, but here's how you'd do it:
a simple javascript file:
//test.js
var myArray = [];
myArray[0] = 'Something';
myArray[1] = 'To';
myArray[2] = 'look';
myArray[3] = 'at';
//ScriptTest.java
import javax.script.*;
import sun.org.mozilla.javascript.internal.NativeArray;
import java.io.FileReader;
class ScriptTest {
  public static void main(String[] argv) throws Exception {
    ScriptEngine js = new ScriptEngineManager().getEngineByName("javascript");
    FileReader script = new FileReader("test.js");
    js.eval(script);
    NativeArray array = (NativeArray)js.get("myArray");
    for(int i = 0; i < array.getLength(); i++)
      System.out.printf("Object: %s\n", array.get(i, array));
}Now, since NativeArray is an internal class, you'll need to add rt.jar to your bootclasspath:
javac -bootclasspath JAVA_HOME/lib/rt.jar ScriptTest.javaSee. Told you it was a hack. :-)