Package org.threadly.concurrent.wrapper.interceptor

Class PrioritySchedulerTaskInterceptor

java.lang.Object

org.threadly.concurrent.wrapper.interceptor.ExecutorTaskInterceptor

org.threadly.concurrent.wrapper.interceptor.SubmitterSchedulerTaskInterceptor

org.threadly.concurrent.wrapper.interceptor.SchedulerServiceTaskInterceptor

org.threadly.concurrent.wrapper.interceptor.PrioritySchedulerTaskInterceptor

All Implemented Interfaces:

java.util.concurrent.Executor, PrioritySchedulerService, SchedulerService, SubmitterExecutor, SubmitterScheduler

public class PrioritySchedulerTaskInterceptor
extends SchedulerServiceTaskInterceptor
implements PrioritySchedulerService

Class to wrap PrioritySchedulerService pool so that tasks can be intercepted and either wrapped, or modified, before being submitted to the pool. This class can be passed a lambda to PrioritySchedulerTaskInterceptor(PrioritySchedulerService, BiFunction)}, or SubmitterSchedulerTaskInterceptor.wrapTask(Runnable, boolean) can be overridden to provide the task which should be submitted to the PrioritySchedulerService. Please see the javadocs of SubmitterSchedulerTaskInterceptor.wrapTask(Runnable, boolean) for more details about ways a task can be modified or wrapped.

Other variants of task wrappers: ExecutorTaskInterceptor, SubmitterSchedulerTaskInterceptor, PrioritySchedulerTaskInterceptor.

Since:

4.6.0

Constructor Summary

Constructors

Constructor	Description
PrioritySchedulerTaskInterceptor(PrioritySchedulerService parentScheduler, java.util.function.BiFunction<java.lang.Runnable,java.lang.Boolean,java.lang.Runnable> taskManipulator)	Constructs a wrapper for PrioritySchedulerService pool so that tasks can be intercepted and modified, before being submitted to the pool.

Method Summary

Modifier and Type	Method	Description
void	execute(java.lang.Runnable task, TaskPriority priority)	Executes the task as soon as possible for the given priority.
TaskPriority	getDefaultPriority()	Get the default priority for the scheduler.
long	getMaxWaitForLowPriority()	Getter for the amount of time a low priority task will wait during thread contention before it is eligible for execution.
int	getQueuedTaskCount(TaskPriority priority)	Returns a count of how many tasks are either waiting to be executed, or are scheduled to be executed at a future point for a specific priority.
int	getWaitingForExecutionTaskCount(TaskPriority priority)	Returns a count of how many tasks are either waiting to be executed for a specific priority.
void	schedule(java.lang.Runnable task, long delayInMs, TaskPriority priority)	Schedule a task with a given delay and a specified priority.
void	scheduleAtFixedRate(java.lang.Runnable task, long initialDelay, long period, TaskPriority priority)	Schedule a fixed rate recurring task to run.
void	scheduleWithFixedDelay(java.lang.Runnable task, long initialDelay, long recurringDelay, TaskPriority priority)	Schedule a fixed delay recurring task to run.
<T> ListenableFuture<T>	submit(java.lang.Runnable task, T result, TaskPriority priority)	Submit a task to run as soon as possible for the given priority.
<T> ListenableFuture<T>	submit(java.util.concurrent.Callable<T> task, TaskPriority priority)	Submit a Callable to run as soon as possible for the given priority.
<T> ListenableFuture<T>	submitScheduled(java.lang.Runnable task, T result, long delayInMs, TaskPriority priority)	Schedule a task with a given delay and a specified priority.
<T> ListenableFuture<T>	submitScheduled(java.util.concurrent.Callable<T> task, long delayInMs, TaskPriority priority)	Schedule a Callable with a given delay.

Methods inherited from class org.threadly.concurrent.wrapper.interceptor.SchedulerServiceTaskInterceptor

getActiveTaskCount, getQueuedTaskCount, getWaitingForExecutionTaskCount, isShutdown, remove, remove

Methods inherited from class org.threadly.concurrent.wrapper.interceptor.SubmitterSchedulerTaskInterceptor

schedule, scheduleAtFixedRate, scheduleWithFixedDelay, submitScheduled, submitScheduled, wrapTask, wrapTask

Methods inherited from class org.threadly.concurrent.wrapper.interceptor.ExecutorTaskInterceptor

execute, submit, submit

Methods inherited from class java.lang.Object

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

Methods inherited from interface java.util.concurrent.Executor

execute

Methods inherited from interface org.threadly.concurrent.PrioritySchedulerService

submit, submitScheduled

Methods inherited from interface org.threadly.concurrent.SchedulerService

getActiveTaskCount, getQueuedTaskCount, getWaitingForExecutionTaskCount, isShutdown, remove, remove

Methods inherited from interface org.threadly.concurrent.SubmitterExecutor

submit, submit, submit

Methods inherited from interface org.threadly.concurrent.SubmitterScheduler

schedule, scheduleAtFixedRate, scheduleWithFixedDelay, submitScheduled, submitScheduled, submitScheduled

Constructor Detail

PrioritySchedulerTaskInterceptor

public PrioritySchedulerTaskInterceptor(PrioritySchedulerService parentScheduler,
                                        java.util.function.BiFunction<java.lang.Runnable,java.lang.Boolean,java.lang.Runnable> taskManipulator)

Constructs a wrapper for PrioritySchedulerService pool so that tasks can be intercepted and modified, before being submitted to the pool.

Parameters:

parentScheduler - An instance of PrioritySchedulerService to wrap

taskManipulator - A lambda to manipulate a Runnable that was submitted for execution

Method Detail

execute

public void execute(java.lang.Runnable task,
                    TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Executes the task as soon as possible for the given priority.

Specified by:

execute in interface PrioritySchedulerService

Parameters:

task - runnable to execute

priority - priority for task to get available thread to run on

submit

public <T> ListenableFuture<T> submit(java.lang.Runnable task,
                                      T result,
                                      TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Submit a task to run as soon as possible for the given priority. There is a slight increase in load when using submit over execute. So this should only be used when the future is necessary.

The Future.get() method will return the provided result once the runnable has completed.

Specified by:

submit in interface PrioritySchedulerService

Type Parameters:

T - type of result returned from the future

Parameters:

task - runnable to be executed

result - result to be returned from resulting future .get() when runnable completes

priority - priority for task to get available thread to run on

Returns:

a future to know when the task has completed

submit

public <T> ListenableFuture<T> submit(java.util.concurrent.Callable<T> task,
                                      TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Submit a Callable to run as soon as possible for the given priority. This is needed when a result needs to be consumed from the callable.

Specified by:

submit in interface PrioritySchedulerService

Type Parameters:

T - type of result returned from the future

Parameters:

task - callable to be executed

priority - priority for task to get available thread to run on

Returns:

a future to know when the task has completed and get the result of the callable

schedule

public void schedule(java.lang.Runnable task,
                     long delayInMs,
                     TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Schedule a task with a given delay and a specified priority.

Specified by:

schedule in interface PrioritySchedulerService

Parameters:

task - runnable to execute

delayInMs - time in milliseconds to wait to execute task

priority - priority for task to get available thread to run on

submitScheduled

public <T> ListenableFuture<T> submitScheduled(java.lang.Runnable task,
                                               T result,
                                               long delayInMs,
                                               TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Schedule a task with a given delay and a specified priority.

The Future.get() method will return the provided result once the runnable has completed.

Specified by:

submitScheduled in interface PrioritySchedulerService

Type Parameters:

T - type of result returned from the future

Parameters:

task - runnable to execute

result - result to be returned from resulting future .get() when runnable completes

delayInMs - time in milliseconds to wait to execute task

priority - priority for task to get available thread to run on

Returns:

a future to know when the task has completed

submitScheduled

public <T> ListenableFuture<T> submitScheduled(java.util.concurrent.Callable<T> task,
                                               long delayInMs,
                                               TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Schedule a Callable with a given delay. This is needed when a result needs to be consumed from the callable.

Specified by:

submitScheduled in interface PrioritySchedulerService

Type Parameters:

T - type of result returned from the future

Parameters:

task - callable to be executed

delayInMs - time in milliseconds to wait to execute task

priority - priority for task to get available thread to run on

Returns:

a future to know when the task has completed and get the result of the callable

scheduleWithFixedDelay

public void scheduleWithFixedDelay(java.lang.Runnable task,
                                   long initialDelay,
                                   long recurringDelay,
                                   TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Schedule a fixed delay recurring task to run. The recurring delay time will be from the point where execution has finished. So the execution frequency is the recurringDelay + runtime for the provided task.

Unlike ScheduledExecutorService if the task throws an exception, subsequent executions are NOT suppressed or prevented. So if the task throws an exception on every run, the task will continue to be executed at the provided recurring delay (possibly throwing an exception on each execution).

Specified by:

scheduleWithFixedDelay in interface PrioritySchedulerService

Parameters:

task - runnable to be executed

initialDelay - delay in milliseconds until first run

recurringDelay - delay in milliseconds for running task after last finish

priority - priority for task to get available thread to run on

scheduleAtFixedRate

public void scheduleAtFixedRate(java.lang.Runnable task,
                                long initialDelay,
                                long period,
                                TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Schedule a fixed rate recurring task to run. The recurring delay will be the same, regardless of how long task execution takes. A given runnable will not run concurrently (unless it is submitted to the scheduler multiple times). Instead of execution takes longer than the period, the next run will occur immediately (given thread availability in the pool).

Unlike ScheduledExecutorService if the task throws an exception, subsequent executions are NOT suppressed or prevented. So if the task throws an exception on every run, the task will continue to be executed at the provided recurring delay (possibly throwing an exception on each execution).

Specified by:

scheduleAtFixedRate in interface PrioritySchedulerService

Parameters:

task - runnable to be executed

initialDelay - delay in milliseconds until first run

period - amount of time in milliseconds between the start of recurring executions

priority - priority for task to get available thread to run on

getDefaultPriority

public TaskPriority getDefaultPriority()

Description copied from interface: PrioritySchedulerService

Get the default priority for the scheduler.

Specified by:

getDefaultPriority in interface PrioritySchedulerService

Returns:

the set default task priority

getMaxWaitForLowPriority

public long getMaxWaitForLowPriority()

Description copied from interface: PrioritySchedulerService

Getter for the amount of time a low priority task will wait during thread contention before it is eligible for execution.

Specified by:

getMaxWaitForLowPriority in interface PrioritySchedulerService

Returns:

currently set max wait for low priority task

getQueuedTaskCount

public int getQueuedTaskCount(TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Returns a count of how many tasks are either waiting to be executed, or are scheduled to be executed at a future point for a specific priority. This can indicate pool back pressure, but it can also just indicate generally scheduled tasks. It's computationally cheaper than PrioritySchedulerService.getWaitingForExecutionTaskCount(TaskPriority).

Specified by:

getQueuedTaskCount in interface PrioritySchedulerService

Parameters:

priority - priority for tasks to be counted

Returns:

quantity of tasks waiting execution or scheduled to be executed later

getWaitingForExecutionTaskCount

public int getWaitingForExecutionTaskCount(TaskPriority priority)

Description copied from interface: PrioritySchedulerService

Returns a count of how many tasks are either waiting to be executed for a specific priority. A value here can indicate the pool is being starved for threads.

Specified by:

getWaitingForExecutionTaskCount in interface PrioritySchedulerService

Parameters:

priority - priority for tasks to be counted

Returns:

quantity of tasks waiting execution