In my project, I need to execute multiple (dosens, even hundreds) JavaScript
files at the same time. And for each script file, I need to register a bean
object for it. I need to use that bean in my script file, e.g.
myBeanName.method1(). But for each scipt, the bean object should be different.
Also, I need to be able to stop specific script files at the run time.
To satisfy all these requirements, I start a new BSFManager() for each script
file:
...
Map threadMap = new Hashtable(); //
...
...
for( each scriptFileName ) {
Thread t = new Thread(){
public void run() {
BSFManager manager = new BSFManager();
String lang = "JavaScript";
//declare the specific bean object for the script file
manager.declareBean("beanName", beanObjectForScriptI, MyBeanClass.class );
manager.exec( lang,
"Java", 0, 0,
IOUtils.getStringFromReader(new FileReader(scriptFileName) ));
}
};
threadMap.put( scriptFileName, t ); //keep reference of thread of each script
file engie
}
Then, later when I call beanName.method1() in each script file, I am sure I
called it on the correct beanObject instance. Also, I can stop the runnging
script for scriptFileX by:
Thread t = (Thread) threadMap.get( scriptFileX );
t.stop();
But, I have some consern about the drawback which is the overhead of creating a
BSFManager object for each script. By looking at the source code, I notice that
each BSFManager maintain the loaded class of the script engine, e.g.
JavaScriptEngine here. Does that mean I am holding dosens even hundreds
JavaScriptEngine class loaded in the memory by the former code scripet??
Now my question is how big is this overhead? How much memory does it take?
Can I avoid it?
If I do it this way :
BSFManager manager = new BSFManager();
for( each scriptFileName ) {
String lang = "JavaScript";
manager.declareBean("beanName", beanObjectForScriptI, MyBeanClass.class
);
manager.exec( lang,
"Java", 0, 0,
IOUtils.getStringFromReader(new FileReader(scriptFileName) ));
}
I am afraid that the declareBean method could overwrite the previously
declared bean. Also, how can I stop the script execution for certain script
files but keep others running at the runtime?
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