Type Parameters:

T - type of generated objects

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
```
@FunctionalInterface
public interface Gen<T>
```
Generators are the building blocks for providing arbitrary objects.
To ease the creation of Arbitraries, Gen is a FunctionalInterface which extends Function<Random, T>.
Gen objects are obtained via one of the methods choose, fail, frequency, of and oneOf.
Given Gen objects may be transformed using one of the methods filter, map and flatMap.
A simple way to obtain an Arbitrary of a Gen is to call arbitrary(). This will ignore the size hint of Arbitrary.

See Also:

Arbitrary

Method Summary

All Methods Static Methods Instance Methods Abstract Methods Default Methods
Modifier and Type	Method	Description
`T`	`apply(java.util.Random random)`	Functional interface of this generator.
`default Arbitrary<T>`	`arbitrary()`	Converts this Gen to an Arbitrary
`static Gen<java.lang.Character>`	`choose(char... characters)`	Chooses a char from all chars in the array
`static Gen<java.lang.Character>`	`choose(char min, char max)`	Chooses a char between min and max, bounds inclusive and chars distributed according to the underlying random number generator.
`static Gen<java.lang.Double>`	`choose(double min, double max)`	Chooses a double between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
`static Gen<java.lang.Integer>`	`choose(int min, int max)`	Chooses an int between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
`static Gen<java.lang.Long>`	`choose(long min, long max)`	Chooses a long between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
`static <T extends java.lang.Enum<T>> Gen<T>`	`choose(java.lang.Class<T> clazz)`	Chooses an enum value from all the enum constants defined in the enumerated type.
`static <T> Gen<T>`	`choose(java.lang.Iterable<T> values)`	Chooses a value from all values in the iterable
`static <T> Gen<T>`	`choose(T... values)`	Chooses a value from all values in the array.
`static <T> Gen<T>`	`fail()`	A failing generator which throws a RuntimeException("failed").
`static <T> Gen<T>`	`fail(java.lang.String message)`	A failing generator which throws a RuntimeException.
`default Gen<T>`	`filter(java.util.function.Predicate<? super T> predicate)`	Returns a generator based on this generator which produces values that fulfill the given predicate.
`default <U> Gen<U>`	`flatMap(java.util.function.Function<? super T,? extends Gen<? extends U>> mapper)`	Maps generated Ts to Us.
`static <T> Gen<T>`	`frequency(Tuple2<java.lang.Integer,Gen<T>>... generators)`	Chooses one of the given generators according to their frequency.
`static <T> Gen<T>`	`frequency(java.lang.Iterable<Tuple2<java.lang.Integer,Gen<T>>> generators)`	Chooses one of the given generators according to their frequency.
`default Gen<T>`	`intersperse(Gen<T> other)`	Intersperse values from this generator instance with those of another.
`default <U> Gen<U>`	`map(java.util.function.Function<? super T,? extends U> mapper)`	Maps generated Ts to Us.
`static <T> Gen<T>`	`of(T t)`	A generator which constantly returns t.
`static <T> Gen<T>`	`of(T seed, java.util.function.Function<? super T,? extends T> next)`
`static <T> Gen<T>`	`oneOf(Gen<T>... generators)`	Randomly chooses one of the given generators.
`static <T> Gen<T>`	`oneOf(java.lang.Iterable<Gen<T>> generators)`	Randomly chooses one of the given generators.
`default Gen<T>`	`peek(java.util.function.Consumer<? super T> action)`
`default <U> U`	`transform(java.util.function.Function<? super Gen<T>,? extends U> f)`	Transforms this `Gen`.

- Method Detail
 - apply
```
T apply(java.util.Random random)
```
 Functional interface of this generator.
 
 Parameters:
 
 random - a random number generator
 
 Returns:
 
 A generated value of type T.
 - of
```
static <T> Gen<T> of(T t)
```
 A generator which constantly returns t.
 
 Type Parameters:
 
 T - Type of t.
 
 Parameters:
 
 t - A value.
 
 Returns:
 
 A new T generator
 - of
```
static <T> Gen<T> of(T seed,
 java.util.function.Function<? super T,? extends T> next)
```
 - choose
```
static Gen<java.lang.Integer> choose(int min,
 int max)
```
 Chooses an int between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
 Note: min and max are internally swapped if min > max.
 
 Parameters:
 
 min - lower bound
 
 max - upper bound
 
 Returns:
 
 A new int generator
 - choose
```
static Gen<java.lang.Long> choose(long min,
 long max)
```
 Chooses a long between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
 Note: min and max are internally swapped if min > max.
 
 Parameters:
 
 min - lower bound
 
 max - upper bound
 
 Returns:
 
 A new long generator
 - choose
```
static Gen<java.lang.Double> choose(double min,
 double max)
```
 Chooses a double between min and max, bounds inclusive and numbers distributed according to the distribution of the underlying random number generator.
 Note: min and max are internally swapped if min > max.
 
 Parameters:
 
 min - lower bound
 
 max - upper bound
 
 Returns:
 
 A new double generator
 
 Throws:
 
 java.lang.IllegalArgumentException - if min or max is infinite, min or max is not a number (NaN)
 - choose
```
static Gen<java.lang.Character> choose(char min,
 char max)
```
 Chooses a char between min and max, bounds inclusive and chars distributed according to the underlying random number generator.
 Note: min and max are internally swapped if min > max.
 
 Parameters:
 
 min - lower bound
 
 max - upper bound
 
 Returns:
 
 A new char generator
 - choose
```
static Gen<java.lang.Character> choose(char... characters)
```
 Chooses a char from all chars in the array
 
 Parameters:
 
 characters - array with the characters to choose from
 
 Returns:
 
 A new array generator
 - choose
```
static <T extends java.lang.Enum<T>> Gen<T> choose(java.lang.Class<T> clazz)
```
 Chooses an enum value from all the enum constants defined in the enumerated type.
 
 Type Parameters:
 
 T - type of enum constants
 
 Parameters:
 
 clazz - Enum class
 
 Returns:
 
 A new enum generator
 - choose
```
@SafeVarargs
static <T> Gen<T> choose(T... values)
```
 Chooses a value from all values in the array.
 
 Type Parameters:
 
 T - value type
 
 Parameters:
 
 values - array with the values to choose from
 
 Returns:
 
 A new array generator
 - choose
```
static <T> Gen<T> choose(java.lang.Iterable<T> values)
```
 Chooses a value from all values in the iterable
 
 Type Parameters:
 
 T - value type
 
 Parameters:
 
 values - iterable with the values to choose from.
 
 Returns:
 
 A new iterable generator
 - fail
```
static <T> Gen<T> fail()
```
 A failing generator which throws a RuntimeException("failed").
 
 Type Parameters:
 
 T - Type of values theoretically generated.
 
 Returns:
 
 A new generator which always fails with the message "failed"
 - fail
```
static <T> Gen<T> fail(java.lang.String message)
```
 A failing generator which throws a RuntimeException.
 
 Type Parameters:
 
 T - Type of values theoretically generated.
 
 Parameters:
 
 message - Message thrown.
 
 Returns:
 
 A new generator which always fails with the given message
 - frequency
```
@SafeVarargs
static <T> Gen<T> frequency(Tuple2<java.lang.Integer,Gen<T>>... generators)
```
 Chooses one of the given generators according to their frequency. Only generators with positive frequencies are used in returned generator.
 
 Type Parameters:
 
 T - Type to be generated
 
 Parameters:
 
 generators - A non-empty array of Tuples (frequency, generator)
 
 Returns:
 
 A new T generator
 
 Throws:
 
 java.lang.NullPointerException - if generators is null
 
 java.lang.IllegalArgumentException - if generators doesn't contain any generator with positive frequency
 - frequency
```
static <T> Gen<T> frequency(java.lang.Iterable<Tuple2<java.lang.Integer,Gen<T>>> generators)
```
 Chooses one of the given generators according to their frequency. Only generators with positive frequencies ares used in returned generator.
 
 Type Parameters:
 
 T - Type to be generated
 
 Parameters:
 
 generators - A non-empty traversable of Tuples (frequency, generator)
 
 Returns:
 
 A new T generator
 
 Throws:
 
 java.lang.NullPointerException - if generators is null
 
 java.lang.IllegalArgumentException - if generators doesn't contain any generator with positive frequency
 - intersperse
```
default Gen<T> intersperse(Gen<T> other)
```
 Intersperse values from this generator instance with those of another.
 
 Parameters:
 
 other - another T generator to accept values from.
 
 Returns:
 
 A new T generator
 - oneOf
```
@SafeVarargs
static <T> Gen<T> oneOf(Gen<T>... generators)
```
 Randomly chooses one of the given generators.
 
 Type Parameters:
 
 T - Type to be generated
 
 Parameters:
 
 generators - A non-empty array of generators
 
 Returns:
 
 A new T generator
 
 Throws:
 
 java.lang.NullPointerException - if generators is null
 
 java.lang.IllegalArgumentException - if generators is empty
 - oneOf
```
static <T> Gen<T> oneOf(java.lang.Iterable<Gen<T>> generators)
```
 Randomly chooses one of the given generators.
 
 Type Parameters:
 
 T - Type to be generated
 
 Parameters:
 
 generators - A non-empty Iterable of generators
 
 Returns:
 
 A new T generator
 
 Throws:
 
 java.lang.NullPointerException - if generators is null
 
 java.lang.IllegalArgumentException - if generators is empty
 - arbitrary
```
default Arbitrary<T> arbitrary()
```
 Converts this Gen to an Arbitrary
 
 Returns:
 
 An arbitrary which returns this generator regardless of the provided size hint n
 - filter
```
default Gen<T> filter(java.util.function.Predicate<? super T> predicate)
```
 Returns a generator based on this generator which produces values that fulfill the given predicate.
 
 Parameters:
 
 predicate - A predicate
 
 Returns:
 
 A new generator
 - flatMap
```
default  Gen flatMap(java.util.function.Function<? super T,? extends Gen<? extends U>> mapper)
```
 Maps generated Ts to Us.
 
 Type Parameters:
 
 U - Type of generated objects of the new generator
 
 Parameters:
 
 mapper - A function that maps a generated T to a new generator which generates objects of type U.
 
 Returns:
 
 A new generator
 - map
```
default  Gen map(java.util.function.Function<? super T,? extends U> mapper)
```
 Maps generated Ts to Us.
 
 Type Parameters:
 
 U - Type of the mapped object
 
 Parameters:
 
 mapper - A function that maps a generated T to an object of type U.
 
 Returns:
 
 A new generator
 - peek
```
default Gen<T> peek(java.util.function.Consumer<? super T> action)
```
 - transform
```
default  U transform(java.util.function.Function<? super Gen<T>,? extends U> f)
```
 Transforms this Gen.
 
 Type Parameters:
 
 U - Type of transformation result
 
 Parameters:
 
 f - A transformation
 
 Returns:
 
 An instance of type U
 
 Throws:
 
 java.lang.NullPointerException - if f is null

Interface Gen<T>

Method Summary

Method Detail

apply

of

of

choose

choose

choose

choose

choose

choose

choose

choose

fail

fail

frequency

frequency

intersperse

oneOf

oneOf

arbitrary

filter

flatMap

map

peek

transform