com.inductiveautomation.ignition.gateway.tasks

Interface Task

All Known Implementing Classes:

AbstractTask

public interface Task

A Task is an executable entity that is run by the gateway. It is a long running operation that can be paused, canceled, and monitored. A Task instance is created through a TaskType, in conjunction with task settings. It is configured in the gateway web UI, according to the TaskType.

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static interface	Task.TaskStateModel If a task can be suspended and resumed, this is an arbitrary state that will be used to resume.

Method Summary

Modifier and Type	Method and Description
void	cancel(long timeoutMS) When called, the task should stop as quickly as possible.
java.util.List<java.lang.Throwable>	getErrors() Returns a List of all the exceptions that occurred when running a task.
java.util.UUID	getId()
void	resume(Task.TaskStateModel state)
void	run(TaskContext context) Executes the task.
java.util.Optional<Task.TaskStateModel>	suspend(long timeoutMS) When called, the task should stop as quickly as possible.

Method Detail

getId

java.util.UUID getId()

run

void run(TaskContext context)
  throws java.lang.Exception

Executes the task. This function should block until completion. If there is a problem executing the task, an exception should be thrown. It is important to note that while this function should block, the task must expect that at some point, suspend or cancel may be called.

Throws:

java.lang.Exception

suspend

java.util.Optional<Task.TaskStateModel> suspend(long timeoutMS)
                                         throws java.util.concurrent.TimeoutException,
                                                java.lang.InterruptedException

When called, the task should stop as quickly as possible. If the task is able to resume, it should return a state that will be provided to it when restarted. If this function returns an empty value, it will not be resumed. If appropriate, the call should try to implement the timeout restriction passed in. A timeout of 0 means "no timeout".

Throws:

java.util.concurrent.TimeoutException

java.lang.InterruptedException

resume

void resume(Task.TaskStateModel state)

cancel

void cancel(long timeoutMS)
     throws java.util.concurrent.TimeoutException,
            java.lang.InterruptedException

When called, the task should stop as quickly as possible. If appropriate, the call should try to implement the timeout restriction passed in. A timeout of 0 means "no timeout".

Throws:

java.util.concurrent.TimeoutException

java.lang.InterruptedException

getErrors

java.util.List<java.lang.Throwable> getErrors()

Returns a List of all the exceptions that occurred when running a task. If no exceptions occurred, an empty List is returned.