/**
* Returns <code>true</code> if this task is blocked by its dependencies; <code>false</code>
* otherwise.
*
* <p>A task is blocked by dependencies if a task with an ID matching one or more of the
* dependencies is running or in the queue before this one.
*
* <p><strong>ATTENTION: Make sure this is only called from inside a synchronized block!</strong>
*
* @return
*/
private boolean isBlockedByDependencies() {
for (ProgressThread pg : currentThreads) {
if (dependencies.contains(pg.getID())) {
return true;
}
}
// now check tasks in queue as there might be a dependency waiting for one himself
for (ProgressThread pg : queuedThreads) {
// loop over queued tasks until we reach ourself, if no dependencies have been found
// by then, we can start!
if (pg.equals(this)) {
break;
}
if (dependencies.contains(pg.getID())) {
return true;
}
}
return false;
}
/**
* Removes all queued threads that depend on the progress threads with the provided IDs. Also all
* thread that depend on the threads that have been removed are removed recursively.
*
* <p><strong>ATTENTION: Make sure this is only called from inside a synchronized block!</strong>
*
* @param ids the progress thread IDs the queued progress threads should be checked for
*/
private static final void removeQueuedThreadsWithDependency(String... ids) {
Iterator<ProgressThread> iterator = queuedThreads.iterator();
// iterator over queued threads and remove the remove the ones that depend on one of the
// provided IDs
Set<String> cancelledThreads = new HashSet<>();
while (iterator.hasNext()) {
ProgressThread pg = iterator.next();
if (!Collections.disjoint(Arrays.asList(ids), pg.getDependencies())) {
iterator.remove();
cancelledThreads.add(pg.getID());
}
}
// also remove all the ones depending on the ones that have been cancelled.
if (!cancelledThreads.isEmpty()) {
removeQueuedThreadsWithDependency(
cancelledThreads.toArray(new String[cancelledThreads.size()]));
}
}
