Package org.variantsync.diffdetective.parallel

Class ScheduledTasksIterator<T>

java.lang.Object

org.variantsync.diffdetective.parallel.ScheduledTasksIterator<T>

All Implemented Interfaces:

AutoCloseable, Iterator<T>

public class ScheduledTasksIterator<T>
extends Object
implements Iterator<T>, AutoCloseable

An iterator over the results of computations run in other threads. The results of the given tasks can be received in the correct order using next(). That means the next() method is deterministic if all tasks are deterministic.

Upon creation of a ScheduledTasksIterator, all given tasks are scheduled for execution. However, the results of these tasks become available in the same order as the tasks have been provided. This means, that the iterator will block until the result of the next task is available, even if all other remaining tasks are complete.

Field Summary

Fields

Modifier and Type	Field	Description
private final LinkedList<Future<T>>	futures
private final Iterator<? extends Callable<T>>	remainingTasks
private final ExecutorService	threadPool

Constructor Summary

Constructors

Constructor	Description
ScheduledTasksIterator(Iterable<? extends Callable<T>> tasks, int nThreads)	Starts scheduling tasks in nThreads other threads.
ScheduledTasksIterator(Iterator<? extends Callable<T>> tasks, int nThreads)	Starts scheduling tasks in nThreads other threads.

Method Summary

Modifier and Type	Method	Description
void	close()	Stops all scheduled tasks and releases the used thread resources.
boolean	hasNext()
T	next()	Waits for the next task and retrieves its result.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Methods inherited from interface java.util.Iterator

forEachRemaining, remove

Field Details

remainingTasks

private final Iterator<? extends Callable<T>> remainingTasks

futures

private final LinkedList<Future<T>> futures

threadPool

private final ExecutorService threadPool

Constructor Details

ScheduledTasksIterator

public ScheduledTasksIterator(Iterator<? extends Callable<T>> tasks,
 int nThreads)

Starts scheduling tasks in nThreads other threads. The results of these tasks can be retrieved by calling next(). The order of these results is deterministic and is the same as the order of the provided tasks.

Parameters:

tasks - the tasks which will be executed in other threads

nThreads - the number of threads which work on tasks in parallel

ScheduledTasksIterator

public ScheduledTasksIterator(Iterable<? extends Callable<T>> tasks,
 int nThreads)

Starts scheduling tasks in nThreads other threads.

Parameters:

tasks - the tasks which will be executed in other threads

nThreads - the number of threads which work on tasks in parallel

Method Details

hasNext

public boolean hasNext()

Specified by:

hasNext in interface Iterator<T>

next

public T next()

Waits for the next task and retrieves its result. The order of the results corresponds to the order of tasks given in the constructor. Each call to next schedules a new task if any task is remaining.

Specified by:

next in interface Iterator<T>

Returns:

one result of a tasks given in ScheduledTasksIterator

Throws:

RuntimeException - if a thread is interrupted or a task couldn't be executed

close

public void close()

Stops all scheduled tasks and releases the used thread resources.

Specified by:

close in interface AutoCloseable