Blogging Roller

After some late night hacking sessions, I've been able to rip Cocoon's Control Flow component free of Cocoon. I removed all dependencies on Cocoon and Avalon and pared my standalone version of Control Flow down to only 14 classes and a couple of JavaScript functions.

Below is the simple JavaScript code that I'm using to test Control Flow. This code will eventually run on the server side and will send a web page to the user when it needs input. The forwardAndWait() method puts the name of the page or Struts forward into a 'tray' object and suspends execution. Eventually, it will suspend execution of the script, call a JSP page or a Struts forward, and wait for the response to go out and the request to come back in.

function test(tray) 
{
   log.info("I called my script!");
   forwardAndWait(tray, "page1.html");
    
   log.info("I'm back in the script");
   forwardAndWait(tray, "page2.html");

   log.info("all done!");
}

Below is the code I'm using to run and test this script. Step #1 sets up the 'tray' that I use to get the forward name and continuation id out of the JavaScript world. I introduced the tray concept, and I don't really like it but I'm not sure how else to get the values I need out of JavaScript. Step #2 and #4 are the interesting bits. Step #2 calls the JavaScript method, which executes and then suspends the script execution inside the 1st JavaScript forwardAndWait() call. Step #4 resumes execution of the script using the continuation id found in the tray.

JavaScriptInterpreter interp = new JavaScriptInterpreter();      
interp.initialize();     
interp.register("C:\\allfiles\\scratch\\StrutsFlow\\src\\flow\\system.js");
interp.register("C:\\allfiles\\scratch\\StrutsFlow\\tests\\flow\\test.js");
      
Scriptable s = interp.enterContext();
      
// 1. setup tray param to hold forward
List params = new LinkedList();
List tray = new LinkedList();
params.add(new Argument("tray", tray));

// 2. call function
interp.callFunction("test", params);
     
// 3. funcion suspended, now tray should contain forward name
assertTrue(((String)tray.get(0)).equals("page1.html"));
// and the continuation id
String kontid = (String)tray.get(1);
      
// 4. resume exection of script using that contination id
interp.handleContinuation(kontid, new LinkedList());
      
// 5. function suspeded again, now tray should contain second forward name
assertTrue(((String)tray.get(0)).equals("page2.html"));
      
// 6. resume function, so it may complete execution
kontid = (String)tray.get(1);
interp.handleContinuation(kontid, new LinkedList());
      
interp.exitContext(s);

And below is the debug output from running the test code above.

JS-INFO: I called my script!
JS-DEBUG: WK: Just Created New Continuation 4d281a763e7c1b3f5a7b4e244b2e224729112160
JS-INFO: I'm back in the script
JS-DEBUG: WK: Just Created New Continuation 877d715e813c5a7c4e7f1a56612826332f528167
JS-INFO: all done!

Next, I'll try to implement the same NumberGuess example from the Control Flow tutorial, but with no Cocoon - only JSP and Servlets.