de.grogra.task
Class Task

java.lang.Object
  de.grogra.task.Task

Direct Known Subclasses:

ConcurrentTasks, PixelwiseRenderer

public abstract class Task
extends java.lang.Object

A Task is used for a complex problem which can be decomposed in several independent PartialTasks. These partial tasks are solved synchronously or asynchronously by a set of Solvers which may work in different threads or even on remote computers.

Author:

Ole Kniemeyer

Constructor Summary

Task()

Method Summary

void	addSolver(Solver s) Adds a solver to this task.
protected abstract void	dispose(PartialTask task) This method is invoked when an active solver is removed or invokes partialTaskDone(Solver) in order to tell this task that the partial task of the solver is no longer processed.
protected abstract boolean	done() Returns true iff the complete task has been solved.
protected void	finishSolve()
int	getSolverCount() Returns the number of solvers for this task.
Solver[]	getSolvers()
boolean	isSolving()
boolean	isStopped() This method returns true iff the method stop() has been invoked on this task.
protected abstract PartialTask	nextPartialTask(int solverIndex) This method returns the next partial task for this task.
void	partialTaskDone(Solver s) This method has to be invoked by a solver if it has completed processing its current partial task.
protected void	prepareSolve()
void	removeSolver(Solver s) Removes a solver from this task.
void	removeSolvers()
void	solve()
void	stop() This method is invoked in order to stop the computation of this task.

Methods inherited from class java.lang.Object

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

Constructor Detail

Task

public Task()

Method Detail

addSolver

public void addSolver(Solver s)

Adds a solver to this task.

Parameters:

s - a solver

dispose

protected abstract void dispose(PartialTask task)

This method is invoked when an active solver is removed or invokes partialTaskDone(Solver) in order to tell this task that the partial task of the solver is no longer processed. Note that the solver may not have completely processed its partial task.

Parameters:

task - partial task which is no longer processed

done

protected abstract boolean done()

Returns true iff the complete task has been solved.

Returns:

has the task been solved?

finishSolve

protected void finishSolve()

getSolverCount

public int getSolverCount()

Returns the number of solvers for this task.

Returns:

number of solvers

getSolvers

public Solver[] getSolvers()

isSolving

public boolean isSolving()

isStopped

public boolean isStopped()

This method returns true iff the method stop() has been invoked on this task.

Returns:

has this task been stopped?

nextPartialTask

protected abstract PartialTask nextPartialTask(int solverIndex)

This method returns the next partial task for this task. If all parts of the task have been solved or currently are being solved, null is returned. However, a later invocation may return a partial task if a currently active solver does not completely solve its partial task.

Parameters:

solverIndex - index of solver which will be used for next task

Returns:

next partial task, or null

partialTaskDone

public void partialTaskDone(Solver s)

This method has to be invoked by a solver if it has completed processing its current partial task. Note that (depending on the specific implementation of Task) a solver may complete processing its partial task without completely solving it. In this case the unsolved part of the partial task is returned as part of later invocations of nextPartialTask(int).

Parameters:

s - the solver which has completed processing its partial task

prepareSolve

protected void prepareSolve()

removeSolver

public void removeSolver(Solver s)

Removes a solver from this task. The method Solver.dispose() is invoked on s.

Parameters:

s - a solver

removeSolvers

public void removeSolvers()

solve

public void solve()

stop

public void stop()

This method is invoked in order to stop the computation of this task.