Enum Class DefaultTaskController.TaskState

java.lang.Object

java.lang.Enum<DefaultTaskController.TaskState>

io.aleph0.yap.core.task.DefaultTaskController.TaskState

All Implemented Interfaces:

Serializable, Comparable<DefaultTaskController.TaskState>, Constable

Enclosing class:

DefaultTaskController<InputT,OutputT>

public static enum DefaultTaskController.TaskState
extends Enum<DefaultTaskController.TaskState>

The internal state of a task. The task starts in the READY state. The controller then moves the task through states according to the various events that occur.

Nested Class Summary

Nested classes/interfaces inherited from class java.lang.Enum

Enum.EnumDesc<E extends Enum<E>>

Enum Constant Summary

Enum Constants

Enum Constant	Description
CANCELED	The task is done processing and has shut down.
CANCELING	The user has requested cancellation and the task is in the process of shutting down.
COMPLETED	The task is done processing and has shut down.
COMPLETING	The task is done processing and is in the process of shutting down.
FAILED	The task is done processing and has shut down.
FAILING	One or more workers have completed exceptionally and the task is in the process of shutting down.
READY	The initial state of the task.
RUNNING	The task is running.

Method Summary

Modifier and Type	Method	Description
DefaultTaskController.TaskPhase	getPhase()
abstract DefaultTaskController.TaskState	to(DefaultTaskController.TaskState target)	Validate the transition from this state to the target state.
static DefaultTaskController.TaskState	valueOf(String name)	Returns the enum constant of this class with the specified name.
static DefaultTaskController.TaskState[]	values()	Returns an array containing the constants of this enum class, in the order they are declared.

Methods inherited from class java.lang.Enum

clone, compareTo, describeConstable, equals, finalize, getDeclaringClass, hashCode, name, ordinal, toString, valueOf

Methods inherited from class java.lang.Object

getClass, notify, notifyAll, wait, wait, wait

Enum Constant Details

READY

public static final DefaultTaskController.TaskState READY

The initial state of the task. On task start, the controller immediately moves to RUNNING.

RUNNING

public static final DefaultTaskController.TaskState RUNNING

The task is running. One or more worker has been started, no workers have completed normally, no workers have completed exceptionally, and the user has not requested cancellation. The controller stays in this state until one of the following events:

• If a worker completes normally, then move to COMPLETING
• If a worker completes exceptionally, then move to FAILING.
• If the user requests cancellation, then move to CANCELING.

COMPLETING

public static final DefaultTaskController.TaskState COMPLETING

The task is done processing and is in the process of shutting down. The following conditions must be true:

• At least one worker has completed normally
• At least one worker is still running
• No workers have completed exceptionally
• The user has not requested cancellation

The controller stays in this state until one of the following events:

• If the last worker completes normally, then move to COMPLETED.
• If a worker completes exceptionally, then move to FAILING. If it is the last worker, then move to FAILED instead.
• If the user requests cancellation, then move to CANCELING.

CANCELING

public static final DefaultTaskController.TaskState CANCELING

The user has requested cancellation and the task is in the process of shutting down. The following conditions must be true:

• The user has requested cancellation
• At least one worker is still running
• No workers have completed exceptionally

The controller stays in this state until one of the following events:

• If the last worker completes normally or stops, then move to CANCELED.
• If a worker completes exceptionally, then move to FAILING. If it is the last worker, then move to FAILED instead.

FAILING

public static final DefaultTaskController.TaskState FAILING

One or more workers have completed exceptionally and the task is in the process of shutting down. The following conditions must be true:

• At least one worker has completed exceptionally
• At least one worker is still running

The controller stays in this state until one of the following events:

• The last worker normally, exceptionally, or stops, then move to FAILED.

COMPLETED

public static final DefaultTaskController.TaskState COMPLETED

The task is done processing and has shut down. The user did not request cancellation, and all workers have completed normally.

CANCELED

public static final DefaultTaskController.TaskState CANCELED

The task is done processing and has shut down. The user requested cancellation, and all workers either completed normally or stopped.

FAILED

public static final DefaultTaskController.TaskState FAILED

The task is done processing and has shut down. At least one worker completed exceptionally.

Method Details

values

public static DefaultTaskController.TaskState[] values()

Returns an array containing the constants of this enum class, in the order they are declared.

Returns:

an array containing the constants of this enum class, in the order they are declared

valueOf

public static DefaultTaskController.TaskState valueOf(String name)

Returns the enum constant of this class with the specified name. The string must match exactly an identifier used to declare an enum constant in this class. (Extraneous whitespace characters are not permitted.)

Parameters:

name - the name of the enum constant to be returned.

Returns:

the enum constant with the specified name

Throws:

IllegalArgumentException - if this enum class has no constant with the specified name

NullPointerException - if the argument is null

getPhase

public DefaultTaskController.TaskPhase getPhase()

to

public abstract DefaultTaskController.TaskState to(DefaultTaskController.TaskState target)

Validate the transition from this state to the target state. The controller will call this method to validate the transition before moving to the target state. If the transition is valid, the method will return the target state. If the transition is invalid, the method will throw an IllegalStateException.

Parameters:

target - the target state

Returns:

the target state, if the transition is valid

Throws:

IllegalStateException - if the transition is invalid