How can I clear session?

Question

Hi everyone,
I have a little problem, I have a JSP tree. The tree displays structure
of files and subdirectories in specified directory.
When session is empty I call function loadData1() and make tree and put them
into session. But any change in the structure I cannot see, after page
refresh. The change is visible only when I close browser and load again.
here is some code:
// Get Tree from session
     if (jspSession.getValue(SESSION_TREE) != null)
// Get the tree from session
     jspTree = (Tree) jspSession.getValue(SESSION_TREE);
// Get Tree from database or data source
else {
jspTree = loadData1();
session.putValue(SESSION_TREE, (Tree) jspTree);
please help

Answer 1

Hi coolovac,
I know this is about one year after your original post, but in case someone searches for it, here is what you could have done:
Your code above only updates the contents of your tree if there is currently NO tree set on the session. This is because of the else clause of your if-statement:
if (jspSession.getValue(SESSION_TREE) != null){
jspTree = (Tree) jspSession.getValue(SESSION_TREE);
} else {
jspTree = loadData1();
session.putValue(SESSION_TREE, (Tree) jspTree);
Your else clause is what builds the tree instance from the database, and your else clause is only run IF you do not currently have a tree instance in the session (jspSession.getValue(SESSION_TREE) == null). What you need to do when you change something in the database is either:
a) Remove the tree instance from the session. That way your else clause will be run again.
b) If you are using the Jenkov JSP Tree Tag (which I suspect from the above code, it looks like code from the demo), you can add expand and collapse listeners to the Tree instance. These listeners can then load child nodes of a node when that node is expanded. That will give dynamic updates of the tree.
You can find the Jenkov JSP Tree Tag here, if you are not already using it:
http://www.jenkov.dk/projects/treetag/treetag.jsp