net.jqwik.api.state

Interface Chain<T>

Type Parameters:

T - The type of state to be transformed in a chain

All Superinterfaces:

java.lang.Iterable<T>

@API(status=EXPERIMENTAL,
     since="1.7.0")
public interface Chain<T>
extends java.lang.Iterable<T>

A chain represents a series of states of type T in which the previous state is somehow transformed into the next state. Transformers are used to transform a state into the next state. The term chain is used in relation to mathematical concepts like Markov chains.

State instances can be mutable or immutable.

Chains can be generated through startWith(Supplier).

See Also:

Transformer

Nested Class Summary

Nested Classes

Modifier and Type	Interface and Description
static class	Chain.ChainFacade

Method Summary

Modifier and Type	Method and Description
default java.util.Iterator<T>	iterator()
int	maxTransformations() The maximum number of transformations that a chain can go through.
java.util.Iterator<T>	start() The Iterator will iterate through elements representing states in order, i.e. their number is one higher than the number of transformations applied to the initial state.
static <T> ChainArbitrary<T>	startWith(java.util.function.Supplier<? extends T> initialSupplier) Create arbitrary for chains with a certain initial state.
java.util.List<java.lang.String>	transformations() Return list of all applied transformations as far as iterators have been used.
java.util.List<Transformer<T>>	transformers() Return list of all used transformer instances.

Methods inherited from interface java.lang.Iterable

forEach, spliterator

Method Detail

startWith

static <T> ChainArbitrary<T> startWith(java.util.function.Supplier<? extends T> initialSupplier)

Create arbitrary for chains 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

start

java.util.Iterator<T> start()

The Iterator will iterate through elements representing states in order, i.e. their number is one higher than the number of transformations applied to the initial state.

Mind that the next state element can depend on both the previous state and (pseudo-)randomness. Several iterators must always produce the same "chain" of states. Each iterator will start with a new instance of the initial state.

Returns:

an iterator through all states

iterator

default java.util.Iterator<T> iterator()

Specified by:

iterator in interface java.lang.Iterable<T>

transformations

java.util.List<java.lang.String> transformations()

Return list of all applied transformations as far as iterators have been used.

For a chain that has not been iterated through this list is empty.

Returns:

list of describing strings

transformers

@API(status=EXPERIMENTAL,
     since="1.7.1")
java.util.List<Transformer<T>> 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.

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

Returns:

list of transformer instances

maxTransformations

int maxTransformations()

The maximum number of transformations that a chain can go through.

Returns:

a number >= 1