Problems using Java code in Flow Scripts

Fri, 05 Sep 2003 09:33:47 -0700

Hello,
 
at first I would say that the concept of Control Flow is one of the best concepts I have ever heard in web development. The use of Flow Script is very easy and fantastic. But there is one big problem for me: It's not possible to use the Flow Script in professional applications! The reason: There are many, many problems of using Java-Code in the Flow Script.
 
An example: Why cause the following lines a NullPointerException
 
function main() {
 
  importClass(Packages.foo.bar.User);
 
  user = new User();
  user.setName("Donald Duck");
  user.setPassword("foo");
  user.setActive(false);
 
  cocoon.sendPage("example.jxt",{"user", user});
}
 
and the following - without the user object as parameter for sendPage - not?
 
function main() {
 
  importClass(Packages.foo.bar.User);
 
  user = new User();
  user.setName("Donald Duck");
  user.setPassword("foo");
  user.setActive(false);
 
  cocoon.sendPage("example.jxt");
} 
 
My JXTemplate looks like the following lines:
 
<?xml version="1.0" encoding="ISO-8859-1"?>
 
<html>
<header>
<titleTest</title>
</header>
<body>
 
    <!-- commenting this doesn't solve the problem --->
    Name: ${user.name}
   
</body>
</html>
 
The object "user" exists at foo.bar and the pipeline works fine, because I had tested it with other calls from the Flow Script. And yes, I have already cleared the "works" directory.
 
But this is not just the only problem. There are many other strange problems using Flow Script:
 
Sometimes - not anytime - after an error executing a Flow Script has occured, the Flow Script file is not longer readable and blocked. Why? Not closed Stream? Only restarting tomcat solves this problem.
 
Using JXForms with JavaBeans containing a String[] Array for example doesn't work. But there is no error message displayed. System, please speak with me! On the other hand, using collections works fine.
 
Sometimes, after I had placed many Java-Code into my Flow Script, the call of the function cocoon.sendPage() has no effect. No error message displayed, too!
 
Has anyone one of these problems, too?
 
It would be nice, if anyone can tell me how to solve these problems, because I love the use of Flow Script and I want to use it in all my future applications. But with these problems, there is no way to do that.
 
Thank you.
 
Stephan Niedermeier
 
 
 
 
 
 
 

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