com.hazelcast.scheduledexecutor

Interface IScheduledExecutorService

All Superinterfaces:

DistributedObject

All Known Implementing Classes:

ClientScheduledExecutorProxy, ScheduledExecutorServiceProxy

@Beta
public interface IScheduledExecutorService
extends DistributedObject

Distributed & durable implementation similar to, but not directly inherited ScheduledExecutorService. IScheduledExecutorService provides similar API to the ScheduledExecutorService with some exceptions but also additional methods like scheduling tasks on a specific member, on a member who is owner of a specific key, executing a tasks on multiple members etc.

Tasks (Runnable and/or Callable) scheduled on any partition through an IScheduledExecutorService, yield some durability characteristics.

• When a node goes down (up to durability config), the scheduled task will get re-scheduled on a replica node.
• In the event of a partition migration, the task will be re-scheduled on the destination node.

Note: The above characteristics don't apply when scheduled on a Member.

Tasks that are holding state that needs to be also durable across partitions, will need to implement the StatefulTask interface.

Upon scheduling a task acquires a resource handler, see ScheduledTaskHandler. The handler is generated before the actual scheduling of the task on the node, which allows for a way to access the future in an event of a node failure immediately after scheduling, and also guarantees no duplicates in the cluster by utilising a unique name per task. A name can also be defined by the user by having the Runnable or Callable implement the NamedTask. Alternatively, one can wrap any task using the TaskUtils.named(String, Callable) or TaskUtils.named(String, Runnable) for simplicity.

One difference of this service in comparison to ScheduledExecutorService is the scheduleAtFixedRate(Runnable, long, long, TimeUnit) which has similar semantic to ScheduledExecutorService.scheduleAtFixedRate(Runnable, long, long, TimeUnit). It guarantees a task won't be executed by multiple threads concurrently. The difference is that this service will skip a scheduled execution if another thread is still running the same task, instead of postponing its execution.

The other difference is this service does not offer an equivalent of ScheduledExecutorService.scheduleWithFixedDelay(Runnable, long, long, TimeUnit)

Method Summary

Modifier and Type	Method and Description
<V> Map<Member,List<IScheduledFuture<V>>>	getAllScheduledFutures() Fetches and returns all scheduled (not disposed yet) futures from all members in the cluster.
<V> IScheduledFuture<V>	getScheduledFuture(ScheduledTaskHandler handler) Creates a new IScheduledFuture from the given handler.
<V> IScheduledFuture<V>	schedule(Callable<V> command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
IScheduledFuture<?>	schedule(Runnable command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
IScheduledFuture<?>	scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period.
<V> Map<Member,IScheduledFuture<V>>	scheduleOnAllMembers(Callable<V> command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on all cluster Members.
Map<Member,IScheduledFuture<?>>	scheduleOnAllMembers(Runnable command, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on all cluster Members.
Map<Member,IScheduledFuture<?>>	scheduleOnAllMembersAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on all cluster Members.
<V> IScheduledFuture<V>	scheduleOnKeyOwner(Callable<V> command, Object key, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on the partition owner of the given key.
IScheduledFuture<?>	scheduleOnKeyOwner(Runnable command, Object key, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on the partition owner of the given key.
IScheduledFuture<?>	scheduleOnKeyOwnerAtFixedRate(Runnable command, Object key, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on the partition owner of the given key.
<V> IScheduledFuture<V>	scheduleOnMember(Callable<V> command, Member member, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay at the given Member.
IScheduledFuture<?>	scheduleOnMember(Runnable command, Member member, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay at the given Member.
IScheduledFuture<?>	scheduleOnMemberAtFixedRate(Runnable command, Member member, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period at the given Member.
<V> Map<Member,IScheduledFuture<V>>	scheduleOnMembers(Callable<V> command, Collection<Member> members, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on all Members given.
Map<Member,IScheduledFuture<?>>	scheduleOnMembers(Runnable command, Collection<Member> members, long delay, TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay on all Members given.
Map<Member,IScheduledFuture<?>>	scheduleOnMembersAtFixedRate(Runnable command, Collection<Member> members, long initialDelay, long period, TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on all Members given.
void	shutdown() Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted.

Methods inherited from interface com.hazelcast.core.DistributedObject

destroy, getName, getPartitionKey, getServiceName

Method Detail

schedule

IScheduledFuture<?> schedule(Runnable command,
                             long delay,
                             TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

schedule

<V> IScheduledFuture<V> schedule(Callable<V> command,
                                 long delay,
                                 TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleAtFixedRate

IScheduledFuture<?> scheduleAtFixedRate(Runnable command,
                                        long initialDelay,
                                        long period,
                                        TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.

Parameters:

command - the task to execute

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMember

IScheduledFuture<?> scheduleOnMember(Runnable command,
                                     Member member,
                                     long delay,
                                     TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay at the given Member.

Parameters:

command - the task to execute

member - the member to execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMember

<V> IScheduledFuture<V> scheduleOnMember(Callable<V> command,
                                         Member member,
                                         long delay,
                                         TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay at the given Member.

Parameters:

command - the task to execute

member - the member to execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMemberAtFixedRate

IScheduledFuture<?> scheduleOnMemberAtFixedRate(Runnable command,
                                                Member member,
                                                long initialDelay,
                                                long period,
                                                TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period at the given Member. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.

Parameters:

command - the task to execute

member - the member to execute the task

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnKeyOwner

IScheduledFuture<?> scheduleOnKeyOwner(Runnable command,
                                       Object key,
                                       long delay,
                                       TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on the partition owner of the given key.

Parameters:

command - the task to execute

key - the key to identify the partition owner, which will execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnKeyOwner

<V> IScheduledFuture<V> scheduleOnKeyOwner(Callable<V> command,
                                           Object key,
                                           long delay,
                                           TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on the partition owner of the given key.

Parameters:

command - the task to execute

key - the key to identify the partition owner, which will execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnKeyOwnerAtFixedRate

IScheduledFuture<?> scheduleOnKeyOwnerAtFixedRate(Runnable command,
                                                  Object key,
                                                  long initialDelay,
                                                  long period,
                                                  TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on the partition owner of the given key. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.

Parameters:

command - the task to execute

key - the key to identify the partition owner, which will execute the task

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnAllMembers

Map<Member,IScheduledFuture<?>> scheduleOnAllMembers(Runnable command,
                                                     long delay,
                                                     TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on all cluster Members.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost. If a new member is added, the task will not get scheduled there automatically.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnAllMembers

<V> Map<Member,IScheduledFuture<V>> scheduleOnAllMembers(Callable<V> command,
                                                         long delay,
                                                         TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on all cluster Members.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost. If a new member is added, the task will not get scheduled there automatically.

Parameters:

command - the task to execute

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnAllMembersAtFixedRate

Map<Member,IScheduledFuture<?>> scheduleOnAllMembersAtFixedRate(Runnable command,
                                                                long initialDelay,
                                                                long period,
                                                                TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on all cluster Members. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost. If a new member is added, the task will not get scheduled there automatically.

Parameters:

command - the task to execute

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMembers

Map<Member,IScheduledFuture<?>> scheduleOnMembers(Runnable command,
                                                  Collection<Member> members,
                                                  long delay,
                                                  TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on all Members given.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost.

Parameters:

command - the task to execute

members - the collections of members - where to execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMembers

<V> Map<Member,IScheduledFuture<V>> scheduleOnMembers(Callable<V> command,
                                                      Collection<Member> members,
                                                      long delay,
                                                      TimeUnit unit)

Creates and executes a one-shot action that becomes enabled after the given delay on all Members given.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost.

Parameters:

command - the task to execute

members - the collections of members - where to execute the task

delay - the time from now to delay execution

unit - the time unit of the delay parameter

Returns:

a ScheduledFuture representing pending completion of the task and whose get() method will return null upon completion

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

scheduleOnMembersAtFixedRate

Map<Member,IScheduledFuture<?>> scheduleOnMembersAtFixedRate(Runnable command,
                                                             Collection<Member> members,
                                                             long initialDelay,
                                                             long period,
                                                             TimeUnit unit)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period on all Members given. Executions will commence after initialDelay then initialDelay+period, then initialDelay + 2 * period, and so on. If any execution of this task takes longer than its period, then subsequent execution will be skipped.
Note: In the event of Member leaving the cluster, for whatever reason, the task is lost.

Parameters:

command - the task to execute

members - the collections of members - where to execute the task

initialDelay - the time to delay first execution

period - the period between successive executions

unit - the time unit of the initialDelay and period parameters

Returns:

a ScheduledFuture representing pending completion of the task, and whose get() method will throw an exception upon cancellation

Throws:

RejectedExecutionException - if the task cannot be scheduled for execution

NullPointerException - if command is null

getScheduledFuture

<V> IScheduledFuture<V> getScheduledFuture(ScheduledTaskHandler handler)

Creates a new IScheduledFuture from the given handler. This is useful in case your member node or client from which the original scheduling happened, went down, and now you want to access the ScheduledFuture again.

Type Parameters:

V - The return type of callable tasks

Parameters:

handler - The handler of the task as found from IScheduledFuture.getHandler()

Returns:

A new IScheduledFuture from the given handler.

getAllScheduledFutures

<V> Map<Member,List<IScheduledFuture<V>>> getAllScheduledFutures()

Fetches and returns all scheduled (not disposed yet) futures from all members in the cluster. If a member has no running tasks for this scheduler, it wont be included in the returned Map.

Returns:

A Map with Member keys and a List of IScheduledFuture found for this scheduler.

shutdown

void shutdown()

Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted. Invocation has no additional effect if already shut down.

This method does not wait for previously submitted tasks to complete execution.