Package net.jqwik.api

Interface Shrinkable<T>

All Superinterfaces:

java.lang.Comparable<Shrinkable<T>>

@API(status=STABLE,
     since="1.0")
public interface Shrinkable<T>
extends java.lang.Comparable<Shrinkable<T>>

Nested Class Summary

Nested Classes

Modifier and Type	Interface	Description
static class	Shrinkable.ShrinkableFacade

Method Summary

Modifier and Type	Method	Description
default Shrinkable<java.lang.Object>	asGeneric()	Sometimes simplifies test writing
default int	compareTo(Shrinkable<T> other)
ShrinkingDistance	distance()
default Shrinkable<T>	filter(java.util.function.Predicate<T> filter)
default <U> Shrinkable<U>	flatMap(java.util.function.Function<T,Arbitrary<U>> flatMapper, int tries, long randomSeed)
default java.util.stream.Stream<Shrinkable<T>>	grow()	Grow a shrinkable to allow broader searching in flat mapped shrinkables
default java.util.Optional<Shrinkable<T>>	grow(Shrinkable<?> before, Shrinkable<?> after)	To be able to "move" values towards the end of collections while keeping some constraint constant it's necessary to grow a shrinkable by what another has been shrunk.
default Shrinkable<T>	makeUnshrinkable()
default <U> Shrinkable<U>	map(java.util.function.Function<T,U> mapper)
java.util.stream.Stream<Shrinkable<T>>	shrink()	Create a new and finite stream of smaller or same size shrinkables; size is measured by distance().
static <T> Shrinkable<T>	supplyUnshrinkable(java.util.function.Supplier<T> supplier, boolean cacheImmutables)
static <T> Shrinkable<T>	unshrinkable(T value)
static <T> Shrinkable<T>	unshrinkable(T value, ShrinkingDistance distance)
T	value()	Create value freshly, so that in case of mutable objects shrinking (and reporting) can rely on untouched values.

Method Detail

unshrinkable

static <T> Shrinkable<T> unshrinkable(T value)

unshrinkable

static <T> Shrinkable<T> unshrinkable(T value,
                                      ShrinkingDistance distance)

supplyUnshrinkable

@API(status=INTERNAL)
static <T> Shrinkable<T> supplyUnshrinkable(java.util.function.Supplier<T> supplier,
                                            boolean cacheImmutables)

value

T value()

Create value freshly, so that in case of mutable objects shrinking (and reporting) can rely on untouched values.

Returns:

An un-changed instance of the value represented by this shrinkable

shrink

@API(status=INTERNAL,
     since="1.3.3")
java.util.stream.Stream<Shrinkable<T>> shrink()

Create a new and finite stream of smaller or same size shrinkables; size is measured by distance().

Same size shrinkables are allowed but they have to iterate towards a single value to prevent endless shrinking. This also means that a shrinkable must never be in its own shrink stream!

Returns:

a finite stream of shrinking options

grow

@API(status=INTERNAL,
     since="1.3.3")
default java.util.Optional<Shrinkable<T>> grow(Shrinkable<?> before,
                                               Shrinkable<?> after)

To be able to "move" values towards the end of collections while keeping some constraint constant it's necessary to grow a shrinkable by what another has been shrunk. One example is keeping a sum of values and still shrinking to the same resulting list.

Parameters:

before - The other shrinkable before shrinking

after - The other shrinkable after shrinking

Returns:

this shrinkable grown by the difference of before and after

grow

@API(status=INTERNAL,
     since="1.3.3")
default java.util.stream.Stream<Shrinkable<T>> grow()

Grow a shrinkable to allow broader searching in flat mapped shrinkables

Returns:

a finite stream of grown values

distance

ShrinkingDistance distance()

asGeneric

@API(status=INTERNAL,
     since="1.2.4")
default Shrinkable<java.lang.Object> asGeneric()

Sometimes simplifies test writing

Returns:

generic version of a shrinkable

map

default <U> Shrinkable<U> map(java.util.function.Function<T,U> mapper)

filter

default Shrinkable<T> filter(java.util.function.Predicate<T> filter)

flatMap

default <U> Shrinkable<U> flatMap(java.util.function.Function<T,Arbitrary<U>> flatMapper,
                                  int tries,
                                  long randomSeed)

compareTo

@API(status=INTERNAL)
default int compareTo(Shrinkable<T> other)

Specified by:

compareTo in interface java.lang.Comparable<T>

makeUnshrinkable

@API(status=INTERNAL)
default Shrinkable<T> makeUnshrinkable()