Activity diagrams are like sequence diagrams in that they show multiple objects co-operating, and like state diagrams in that they show the states of those objects. They are particularly nice for locating and documenting parallel processes.
This activity diagram shows what happens when you click the Go button on the BulkImport frame. LargoRecipes displays an animation on the screen while it checks and imports the files you've selected.
One limitation of activity diagrams is that they do not show interthread communication
very well. There is some traffic between the working thread and the GUI thread: every time the
BulkImportWorker opens a new file, it tells the LargoProgressIndicator
to show the name of that file in the animation frame. However, the diagram makes
it appear that the two threads perform their tasks in total independence. A sequence diagram
would show the interthread communication better, but it's harder to show the conditional logic.
Last updated 25 October 2002
LargoRecipes source code, program, and web site copyright 2001-3 D. Squirrel