com.linkedin.parseq

Class Tuple2TaskDelegate<T1,T2>

java.lang.Object

com.linkedin.parseq.Tuple2TaskDelegate<T1,T2>

All Implemented Interfaces:

Cancellable, Promise<Tuple2<T1,T2>>, Task<Tuple2<T1,T2>>, Tuple2Task<T1,T2>

public class Tuple2TaskDelegate<T1,T2>
extends Object
implements Tuple2Task<T1,T2>

Field Summary

Fields inherited from interface com.linkedin.parseq.Task

_taskDescriptor, LOGGER

Constructor Summary

Constructors

Constructor and Description
Tuple2TaskDelegate(Task<Tuple2<T1,T2>> task)

Method Summary

Modifier and Type	Method and Description
void	addListener(PromiseListener<Tuple2<T1,T2>> listener) Adds a listener to this promise that will be notified when the promise is resolved.
void	await() Blocks the current thread for an unbounded amount of time until the promise has be resolved.
boolean	await(long time, TimeUnit unit) Blocks the current thread for up to the specified amount of time or until the promise has been resolved.
boolean	cancel(Exception reason) Attempts to cancel the object with the given reason.
void	contextRun(Context context, Task<?> parent, Collection<Task<?>> predecessors) Attempts to run the task with the given context.
Tuple2<T1,T2>	get() If the promise's value is set, then this method returns the value.
Throwable	getError() Returns the error in this promise, if there is one.
Long	getId() Unique identifier of the task.
String	getName() Returns the name of this task.
Tuple2<T1,T2>	getOrDefault(Tuple2<T1,T2> defaultValue) Gets the value in this promise or, if the promise contains an error, returns the given default value.
int	getPriority() Returns the priority for this task.
ShallowTrace	getShallowTrace() Returns the ShallowTrace for this task.
ShallowTraceBuilder	getShallowTraceBuilder()
Trace	getTrace() Returns the Trace for this task.
TraceBuilder	getTraceBuilder()
boolean	isDone() Returns true if this promise is resolved.
boolean	isFailed() Returns true if the promise has an error.
boolean	setPriority(int priority) Overrides the priority for this task.
void	setTraceValueSerializer(Function<Tuple2<T1,T2>,String> serializer) Allows adding String representation of value computed by this task to trace.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.linkedin.parseq.Tuple2Task

andThen, andThen, cast, flatMap, flatMap, map, map, onFailure, onFailure, recover, recover, recoverWith, recoverWith, shareable, withSideEffect, withSideEffect, withTimeout

Methods inherited from interface com.linkedin.parseq.Task

action, action, andThen, andThen, andThen, andThen, apply, async, async, async, async, blocking, blocking, callable, callable, failure, failure, flatMap, flatMap, flatten, flatten, fromCompletionStage, fromCompletionStage, map, map, par, par, par, par, par, par, par, par, par, par, par, par, par, par, par, toTry, toTry, transform, transform, value, value, withDelay, withDelay, withRetryPolicy, withRetryPolicy, withRetryPolicy, withRetryPolicy, withSafeSideEffect, withSafeSideEffect, withSafeSideEffect, withSafeSideEffect, withSideEffect, withSideEffect, withSideEffect, withSideEffect, withTimeout

Methods inherited from interface com.linkedin.parseq.promise.Promise

toCompletionStage

Constructor Detail

Tuple2TaskDelegate

public Tuple2TaskDelegate(Task<Tuple2<T1,T2>> task)

Method Detail

cancel

public boolean cancel(Exception reason)

Attempts to cancel the object with the given reason. Check the return value to determine if cancellation was successful. Subsequent calls to cancel will always return false.

Specified by:

cancel in interface Cancellable

Parameters:

reason - an Exception indicating why this object was cancelled

Returns:

true iff the object was successfully cancelled as a result of this invocation.

get

public Tuple2<T1,T2> get()
                  throws PromiseException

If the promise's value is set, then this method returns the value. If the promise has an error, the error is thrown, wrapped in a PromiseException. If the promise has not yet been resolved (i.e. it has no value and no error) then this method raises a PromiseUnresolvedException.

Specified by:

get in interface Promise<Tuple2<T1,T2>>

Returns:

the value of the promise if it is available

Throws:

PromiseException - if the promise has an error

PromiseUnresolvedException - if the promise has not yet been resolved

getError

public Throwable getError()
                   throws PromiseUnresolvedException

Returns the error in this promise, if there is one. If this promise contains a value, then this method will return null. If this promise has no value and no error (i.e. it is unresolved) then a PromiseUnresolvedException is thrown.

Specified by:

getError in interface Promise<Tuple2<T1,T2>>

Returns:

the error contained in this promise, or null if the promise contains a value.

Throws:

PromiseUnresolvedException - if the promise has not yet been resolved

getOrDefault

public Tuple2<T1,T2> getOrDefault(Tuple2<T1,T2> defaultValue)
                           throws PromiseUnresolvedException

Gets the value in this promise or, if the promise contains an error, returns the given default value. This is one mechanism for gracefully handling promise failure.

If the promise has not been resolved then this method will throw PromiseUnresolvedException.

Specified by:

getOrDefault in interface Promise<Tuple2<T1,T2>>

Parameters:

defaultValue - the default value to return if this promise contains an error.

Returns:

the value in this promise or the default value if this promise contains an error.

Throws:

PromiseUnresolvedException - if the promise has not yet been resolved

getName

public String getName()

Returns the name of this task.

Specified by:

getName in interface Task<Tuple2<T1,T2>>

Returns:

the name of this task

getPriority

public int getPriority()

Returns the priority for this task.

Specified by:

getPriority in interface Task<Tuple2<T1,T2>>

Returns:

the priority for this task.

setPriority

public boolean setPriority(int priority)

Overrides the priority for this task. Higher priority tasks will be executed before lower priority tasks in the same context. In most cases, the default priority is sufficient.

The default priority is 0. Use priority < 0 to make a task lower priority and priority > 0 to make a task higher priority.

If the task has already started execution the priority cannot be changed.

Specified by:

setPriority in interface Task<Tuple2<T1,T2>>

Parameters:

priority - the new priority for the task.

Returns:

true if the priority was set; otherwise false.

See Also:

Priority

await

public void await()
           throws InterruptedException

Blocks the current thread for an unbounded amount of time until the promise has be resolved.

For asynchronous workflows, use Promise.addListener(PromiseListener), which will notify the user when the promise is resolved instead of blocking the current thread.

Specified by:

await in interface Promise<Tuple2<T1,T2>>

Throws:

InterruptedException - if the current thread is interrupted

contextRun

public void contextRun(Context context,
                       Task<?> parent,
                       Collection<Task<?>> predecessors)

Attempts to run the task with the given context. This method is reserved for use by Engine and Context.

Specified by:

contextRun in interface Task<Tuple2<T1,T2>>

Parameters:

context - the context to use while running this step

parent - the parent of this task

predecessors - that lead to the execution of this task

await

public boolean await(long time,
                     TimeUnit unit)
              throws InterruptedException

Blocks the current thread for up to the specified amount of time or until the promise has been resolved. If the promise was resolved before the specified time has expired, this method returns true.

For asynchronous workflows, use Promise.addListener(PromiseListener), which will notify the user when the promise is resolved instead of blocking the current thread.

Specified by:

await in interface Promise<Tuple2<T1,T2>>

Parameters:

time - the amount of time to wait

unit - the units for the wait time

Returns:

true if the promise is resolved within the specified time

Throws:

InterruptedException - if the current thread is interrupted

getShallowTrace

public ShallowTrace getShallowTrace()

Returns the ShallowTrace for this task. The ShallowTrace will be a point-in-time snapshot and may change over time until the task is completed.

Specified by:

getShallowTrace in interface Task<Tuple2<T1,T2>>

Returns:

the ShallowTrace related to this task

addListener

public void addListener(PromiseListener<Tuple2<T1,T2>> listener)

Adds a listener to this promise that will be notified when the promise is resolved. If the promise has already been resolved then the listener is notified immediately.

Listener will be called on a thread that completed this promise.

The instance passed in to PromiseListener.onResolved(Promise) method does not have to be the exact same instance the PromiseListener was registered with.

Specified by:

addListener in interface Promise<Tuple2<T1,T2>>

Parameters:

listener - the listener to add to this promise

getTrace

public Trace getTrace()

Returns the Trace for this task. The Trace will be a point-in-time snapshot and may change over time until the task is completed.

Specified by:

getTrace in interface Task<Tuple2<T1,T2>>

Returns:

the Trace related to this task

isDone

public boolean isDone()

Returns true if this promise is resolved. A promise is resolved when it has a value or an error.

Specified by:

isDone in interface Promise<Tuple2<T1,T2>>

Returns:

true if this promise has been resolved.

isFailed

public boolean isFailed()

Returns true if the promise has an error. Errors can retrieved using Promise.getError().

Specified by:

isFailed in interface Promise<Tuple2<T1,T2>>

Returns:

true if the promise has en error.

getId

public Long getId()

Unique identifier of the task.

Specified by:

getId in interface Task<Tuple2<T1,T2>>

Returns:

unique identifier of the task.

setTraceValueSerializer

public void setTraceValueSerializer(Function<Tuple2<T1,T2>,String> serializer)

Description copied from interface: Task

Allows adding String representation of value computed by this task to trace. When this task is finished successfully, value will be converted to String using given serializer and it will be included in this task's trace.

Failures are automatically included in a trace.

Specified by:

setTraceValueSerializer in interface Task<Tuple2<T1,T2>>

Parameters:

serializer - serialized used for converting result of this task to String that will be included in this task's trace.

getShallowTraceBuilder

public ShallowTraceBuilder getShallowTraceBuilder()

Specified by:

getShallowTraceBuilder in interface Task<Tuple2<T1,T2>>

getTraceBuilder

public TraceBuilder getTraceBuilder()

Specified by:

getTraceBuilder in interface Task<Tuple2<T1,T2>>