Package net.jqwik.api.state

Interface ActionChain<S>

  • Type Parameters:
    S - The type of the object going through state transformations
    @API(status=EXPERIMENTAL,
     since="1.7.0")
public interface ActionChain<S>
    A chain of transforming Actions that can be run for values of type S. Since the next action is usually created on demand, the current runState of a chain can be queried.

    By default any action chain instance is not thread safe, i.e. you should not try to invoke run() concurrently.

    • Method Detail

      • startWith

        static <T> ActionChainArbitrary<T> startWith​(java.util.function.Supplier<? extends T> initialSupplier)
        Create arbitrary for a chain with a certain initial state.
        Type Parameters:
        T - The type of state to be transformed through the chain.
        Parameters:
        initialSupplier - function to create the initial state object
        Returns:
        new arbitrary instance

      • transformations

        java.util.List<java.lang.String> transformations()
        Return list of all applied transformations.

        For a chain that has not been run this list is always empty.

        Returns:
        list of describing strings

      • transformers

        @API(status=EXPERIMENTAL,
     since="1.7.1")
java.util.List<Transformer<S>> transformers()
        Return list of all used transformer instances.

        Checking transformer instances - e.g. if they are of a certain implementation type - only makes sense if the transformer's description string is NOT set explicitly, e.g. in an Action's description() method.

        For a chain that has not been run this list is always empty.

        Returns:
        list of transformer instances

      • run

        S run()
        Run the list through all transformations provided by the actions to create it. Stop when either the maximum number of transformations is reached or if a Transformer.END_OF_CHAIN is being applied.
        Returns:
        the last resulting state of running through transformations

      • withInvariant

        default ActionChain<S> withInvariant​(java.util.function.Consumer<S> invariant)
        Add an unlabelled invariant to a sequence.
        Parameters:
        invariant - will be checked after each successful action
        Returns:
        the same chain instance
        See Also:
        withInvariant(String, Consumer)

      • withInvariant

        ActionChain<S> withInvariant​(@Nullable
                             @Nullable java.lang.String label,
                             java.util.function.Consumer<S> invariant)
        Add a labelled invariant to a sequence.
        Parameters:
        label - will show up in error messages when the invariant fails
        invariant - will be checked after each successful action
        Returns:
        the same chain instance
        See Also:
        withInvariant(Consumer)

      • finalState

        java.util.Optional<S> finalState()
        The final state value after running an action chain.
        Returns:
        state or Optional.empty() if chain has not been run

      • running

        ActionChain.RunningState running()
        An action chain can be in different running states: NOT_RUN, RUNNING, FAILED, SUCEEDED
        Returns:
        a state object

      • peek

        ActionChain<S> peek​(java.util.function.Consumer<S> peeker)
        Observe the state transformations of a running chain by adding a peeker to an action chain. The peeker will be called after each successful transformation but before checking invariants.

        There can be more than one peeker.

        Parameters:
        peeker - A consumer of a state object
        Returns:
        the same chain instance