One of the things that are the hardest for Notes Java developers transitioning to developing plug-ins for Notes 8 is handling threading. All access to the Notes backend classes must occur on the Notes thread using NotesJob or a thread statically initialized using NotesThread.sinitThread. This is cumbersome and prone to runtime exceptions making the development process slow and agonizing. Also most interaction is started from the UI thread making the need for handling the Notes thread all too common.
A far better approach, IMHO, would be to not require the programmer to handle the threading all together as there are solutions for this readily available. The solution isn’t hard to do.
In an effort to prove this point I sat down for an hour or so at Lotusphere (I know I’m behind in blogging this) and cooked up a wrapper API that wraps the Notes API and provides access to the Notes backend classes without the need to worry about threading. The Notes API is made up of interfaces which makes it even easier.
The whole concept with the wrapper is that the user can write code like this in an event handler
public void widgetSelected(SelectionEvent event) {
try {
// get value
Session session = NotesPlatform.getInstance().getSession();
Database db = session.getDatabase(null, "names.nsf");
View v = db.getView("($People)");
ViewEntryCollection vec = v.getAllEntries();
// set value in label
lblCount.setText("Found " + vec.getCount() + " contacts...");
// return from event
return;
} catch (Exception e) {
StringWriter sw = new StringWriter();
e.printStackTrace(new PrintWriter(sw));
txtException.setText(sw.toString());
}
}
instead of doing stuff like this which includes two extra jobs and having to make sure that no Notes API access is done from the UI thread:
public void widgetSelected(SelectionEvent event) {
// kick of Notes job to get data
new NotesJob("Some job") {
public IStatus runInNotesThread(ProgressMonitor m)
throws NotesException {
// get value
Session session = NotesPlatform.getInstance().getSession();
Database db = session.getDatabase(null, "names.nsf");
View v = db.getView("($People)");
ViewEntryCollection vec = v.getAllEntries();
// get count into final variable
final int count = vec.getCount();
// kick of new UI job to update UI
new UIJob("Update UI") {
public IStatus runInUIThread(IProgressMonitor monitor) {
// set value in label
lblCount.setText("Found " + count + " contacts...");
return Status.OK_STATUS;
}
}.schedule();
// return
return Status.OK_STATUS;
}
}.schedule();
// return
return;
}
Besides being shorter code-wise the former code is also much easier to read and understand. The performance of the former is somewhat slower than the latter (“native” API) due to context switching but the fact that I could do this is 60 minutes proves that something can and should be done to make plug-in development easier. Imagine what could be done in more time. Tweaking for performance should be possible and easy enough. Also using this wrapper API could be a choice the developer makes – ease of use over performance… It could be a call I as a developer was willing to make.
This could actually be a good idea for a project on OpenNTF. If anyone is interested to join up on the project let me know – I’ll be interested in joining forces with someone.
Tomorrow I’ll blog about how this is done and just how easy it is.
