Sounds like a good optimisation, I'm for it. I agree, don't but all the
tasks in the HashSet, just those you don't want duplicated.
Patricia Shanahan wrote:
TaskManager has a method addIfNew(Task t) that adds a Task if, and
only if, there is no existing task that it equals, according to
.equals comparison.
It has one existing use, adding an AddressTask in
com.sun.jini.reggie.RegistrarImpl. All instances of AddressTask are
added using addIfNew. AddressTask is final, and an AddressTask
considers itself equal only to other instances of AddressTask.
I would like to modify TaskManager so that addIfNew adds the new Task
unless there is an equal Task that was also added using addIfNew. The
new javadoc comment would read:
/**
* Add a new task if it is not equal (using the equals method)
* to any existing active or pending task that was also added
* by this method.
*/
This permits a very simple implementation that does not depend on an
O(n) scan of all existing tasks. addIfNew would add the Task to a
HashSet<Task>, and do the rest of the processing if, and only if, the
HashSet add method returns true. I would remember if a particular Task
came through addIfNew, and if it did it will be removed from the
HashSet on completion or removal.
This implementation would fully meet the needs of the existing use, at
least once I improve the hashCode method in AddressTask.
The problem with putting all added Task instances in the HashSet is
that the add method permits addition of multiple tasks that equal each
other. I could work around that problem, but it would make the code
significantly more complicated, and add work to the normal case of
unconditionally added tasks.
Patricia
