de.esoco.coroutine.step

Class Loop<T>

java.lang.Object

org.obrel.core.RelatedObject

de.esoco.coroutine.CoroutineStep<T,T>

de.esoco.coroutine.step.Loop<T>

All Implemented Interfaces:

de.esoco.lib.property.Fluent<CoroutineStep<T,T>>, org.obrel.core.FluentRelatable<CoroutineStep<T,T>>, org.obrel.core.Relatable

public class Loop<T>
extends CoroutineStep<T,T>

A Coroutine step that loops over another step (which may be a subroutine) as long as a predicate yields TRUE for the input value and/or the current continuation. The looped step get's the loop input value as it's input on the first iteration and must return a value of the same type which will then be used to test the condition before the next loop run.

If more complex conditions need to be checked the loop condition can check relations that have been set in the Continuation by the looped step.

Constructor Summary

Constructors

Constructor and Description
Loop(java.util.function.BiPredicate<? super T,Continuation<?>> fCondition, CoroutineStep<T,T> rLoopedStep) Creates a new instance.

Method Summary

Modifier and Type	Method and Description
protected T	execute(T rValue, Continuation<?> rContinuation) This method must be implemented by subclasses to provide the actual functionality of this step.
static <T> Loop<T>	loopWhile(java.util.function.BiPredicate<? super T,Continuation<?>> pCondition, CoroutineStep<T,T> rLoopedStep) Repeatedly executes a certain step as long as the given condition is TRUE for the current value and the continuation of the execution.
static <T> Loop<T>	loopWhile(java.util.function.Predicate<T> pCondition, CoroutineStep<T,T> rLoopedStep) Repeatedly executes a certain step as long as the given condition is TRUE for the current value.
void	runAsync(java.util.concurrent.CompletableFuture<T> fPreviousExecution, CoroutineStep<T,?> rNextStep, Continuation<?> rContinuation) Runs this execution step asynchronously as a continuation of a previous code execution in a CompletableFuture and proceeds to the next step afterwards.

Methods inherited from class de.esoco.coroutine.CoroutineStep

fail, runBlocking, terminateCoroutine, toString

Methods inherited from class org.obrel.core.RelatedObject

deleteRelation, get, getRelation, getRelations, notifyRelationListeners, readRelations, relationsEqual, relationsHashCode, relationsString, set, set, transform, writeRelations

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.obrel.core.FluentRelatable

with, with, with

Methods inherited from interface org.obrel.core.Relatable

deleteRelation, deleteRelation, deleteRelations, get, get, get, getAll, getRelation, getRelationCount, getRelations, getRelations, hasFlag, hasRelation, hasRelations, init, set, set, set, set, set, streamRelations, transform

Methods inherited from interface de.esoco.lib.property.Fluent

_with

Constructor Detail

Loop

public Loop(java.util.function.BiPredicate<? super T,Continuation<?>> fCondition,
            CoroutineStep<T,T> rLoopedStep)

Creates a new instance.

Parameters:

fCondition - The condition to check for TRUE to continue looping

rLoopedStep - The step to execute in the loop

Method Detail

loopWhile

public static <T> Loop<T> loopWhile(java.util.function.BiPredicate<? super T,Continuation<?>> pCondition,
                                    CoroutineStep<T,T> rLoopedStep)

Repeatedly executes a certain step as long as the given condition is TRUE for the current value and the continuation of the execution. The current value is initialized from the loop input value and updated by the looped step on each iteration.

Parameters:

pCondition - The condition to check for TRUE to continue looping

rLoopedStep - The step to execute in the loop

Returns:

A new step instance

loopWhile

public static <T> Loop<T> loopWhile(java.util.function.Predicate<T> pCondition,
                                    CoroutineStep<T,T> rLoopedStep)

Repeatedly executes a certain step as long as the given condition is TRUE for the current value. The current value is initialized from the loop input value and updated by the looped step on each iteration.

If more complex conditions need to be checked the method loopWhile(BiPredicate, CoroutineStep) can be used to check relations that have been set in the Continuation by the looped step.

Parameters:

pCondition - The condition to check for TRUE to continue looping

rLoopedStep - The step to execute in the loop

Returns:

A new step instance

runAsync

public void runAsync(java.util.concurrent.CompletableFuture<T> fPreviousExecution,
                     CoroutineStep<T,?> rNextStep,
                     Continuation<?> rContinuation)

Runs this execution step asynchronously as a continuation of a previous code execution in a CompletableFuture and proceeds to the next step afterwards.

Subclasses that need to suspend the invocation of the next step until some condition is met (e.g. sending or receiving data has finished) need to override this method and create a Suspension by invoking Continuation.suspend(CoroutineStep, CoroutineStep) on the next step. If the condition that caused the suspension resolves the coroutine execution can be resumed by calling Suspension.resume(Object).

Subclasses that override this method also need to handle errors by terminating any further execution (i.e. not resuming a suspension if such exists) and forwarding the causing exception to Continuation.fail(Throwable).

Overrides:

runAsync in class CoroutineStep<T,T>

Parameters:

fPreviousExecution - The future of the previous code execution

rNextStep - The next step to execute or NULL for none

rContinuation - The continuation of the execution

execute

protected T execute(T rValue,
                    Continuation<?> rContinuation)

This method must be implemented by subclasses to provide the actual functionality of this step.

Specified by:

execute in class CoroutineStep<T,T>

Parameters:

rValue - The input value

rContinuation - The continuation of the execution

Returns:

The result of the execution