Package de.esoco.coroutine.step

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

    • Method Summary

      All Methods Static Methods Instance Methods Concrete Methods 
      Modifier and Type Method Description
      protected T execute​(T input, Continuation<?> continuation)
      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> previousExecution, CoroutineStep<T,​?> nextStep, Continuation<?> continuation)
      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 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 de.esoco.lib.property.Fluent

        _with

      • Methods inherited from interface org.obrel.core.FluentRelatable

        with, with, with

      • Methods inherited from interface org.obrel.core.Relatable

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

    • 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> previousExecution,
                     CoroutineStep<T,​?> nextStep,
                     Continuation<?> continuation)
        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:
        previousExecution - The future of the previous code execution
        nextStep - The next step to execute or NULL for none
        continuation - The continuation of the execution

      • execute

        protected T execute​(T input,
                    Continuation<?> continuation)
        This method must be implemented by subclasses to provide the actual functionality of this step.
        Specified by:
        execute in class CoroutineStep<T,​T>
        Parameters:
        input - The input value
        continuation - The continuation of the execution
        Returns:
        The result of the execution