Predicates (Vavr 0.10.4 API)

java.lang.Object
- io.vavr.Predicates

```
public final class Predicates
extends Object
```
Defines general-purpose predicates which are particularly useful when working with API.Match.

Author:

Daniel Dietrich, Grzegorz Piwowarek

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static <T> Predicate<T>`	`allOf(Predicate<T>... predicates)` A combinator that checks if all of the given `predicates` are satisfied.
`static <T> Predicate<T>`	`anyOf(Predicate<T>... predicates)` A combinator that checks if at least one of the given `predicates` is satisfies.
`static <T> Predicate<Iterable<T>>`	`exists(Predicate<? super T> predicate)` A combinator that checks if one or more elements of an `Iterable` satisfy the `predicate`.
`static <T> Predicate<Iterable<T>>`	`forAll(Predicate<? super T> predicate)` A combinator that checks if all elements of an `Iterable` satisfy the `predicate`.
`static <T> Predicate<T>`	`instanceOf(Class<? extends T> type)` Creates a `Predicate` that tests, if an object is instance of the specified `type`.
`static <T> Predicate<T>`	`is(T value)` Creates a `Predicate` that tests, if an object is equal to the specified `value` using `Objects.equals(Object, Object)` for comparison.
`static <T> Predicate<T>`	`isIn(T... values)` Creates a `Predicate` that tests, if an object is equal to at least one of the specified `values` using `Objects.equals(Object, Object)` for comparison.
`static <T> Predicate<T>`	`isNotNull()` Creates a `Predicate` that tests, if an object is not null
`static <T> Predicate<T>`	`isNull()` Creates a `Predicate` that tests, if an object is null
`static <T> Predicate<T>`	`noneOf(Predicate<T>... predicates)` A combinator that checks if none of the given `predicates` is satisfied.
`static <T> Predicate<T>`	`not(Predicate<? super T> predicate)` Negates a given `Predicate`.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

allOf

@SafeVarargs
public static <T> Predicate<T> allOf(Predicate<T>... predicates)

A combinator that checks if all of the given predicates are satisfied.

By definition allOf is satisfied if the given predicates are empty.


 Predicate<Integer> isGreaterThanOne = i -> i > 1;
 Predicate<Integer> isGreaterThanTwo = i -> i > 2;
 allOf().test(0);                                   // true
 allOf(isGreaterThanOne, isGreaterThanTwo).test(3); // true
 allOf(isGreaterThanOne, isGreaterThanTwo).test(2); // false

Type Parameters:: T - closure over tested object types
Parameters:: predicates - An array of predicates
Returns:: A new Predicate
Throws:: NullPointerException - if predicates is null

anyOf

@SafeVarargs
public static <T> Predicate<T> anyOf(Predicate<T>... predicates)

A combinator that checks if at least one of the given predicates is satisfies.


 Predicate<Integer> isGreaterThanOne = i -> i > 1;
 Predicate<Integer> isGreaterThanTwo = i -> i > 2;
 anyOf().test(0);                                   // false
 anyOf(isGreaterThanOne, isGreaterThanTwo).test(3); // true
 anyOf(isGreaterThanOne, isGreaterThanTwo).test(2); // true
 anyOf(isGreaterThanOne, isGreaterThanTwo).test(1); // false

Type Parameters:: T - closure over tested object types
Parameters:: predicates - An array of predicates
Returns:: A new Predicate
Throws:: NullPointerException - if predicates is null

exists

public static <T> Predicate<Iterable<T>> exists(Predicate<? super T> predicate)

A combinator that checks if one or more elements of an Iterable satisfy the predicate.


 Predicate<Integer> isGreaterThanOne = i -> i > 1;
 Predicate<Iterable<Integer>> existsGreaterThanOne = exists(isGreaterThanOne);
 existsGreaterThanOne.test(List.of(0, 1, 2)); // true
 existsGreaterThanOne.test(List.of(0, 1));    // false

Type Parameters:: T - tested object type
Parameters:: predicate - A Predicate that tests elements of type T
Returns:: A new Predicate
Throws:: NullPointerException - if predicate is null

forAll

public static <T> Predicate<Iterable<T>> forAll(Predicate<? super T> predicate)

A combinator that checks if all elements of an Iterable satisfy the predicate.


 Predicate<Integer> isGreaterThanOne = i -> i > 1;
 Predicate<Iterable<Integer>> forAllGreaterThanOne = forAll(isGreaterThanOne);
 forAllGreaterThanOne.test(List.of(0, 1, 2)); // false
 forAllGreaterThanOne.test(List.of(2, 3, 4)); // true

Type Parameters:: T - tested object type
Parameters:: predicate - A Predicate that tests elements of type T
Returns:: A new Predicate
Throws:: NullPointerException - if predicate is null

instanceOf

@GwtIncompatible
public static <T> Predicate<T> instanceOf(Class<? extends T> type)

Creates a Predicate that tests, if an object is instance of the specified type.


 Predicate<Object> instanceOfNumber = instanceOf(Number.class);
 instanceOfNumber.test(1);    // true
 instanceOfNumber.test("1");  // false

Type Parameters:: T - tested object type
Parameters:: type - A type
Returns:: A new Predicate
Throws:: NullPointerException - if type is null

is
```
public static <T> Predicate<T> is(T value)
```
Creates a Predicate that tests, if an object is equal to the specified value using Objects.equals(Object, Object) for comparison.
```
 Predicate<Integer> isOne = is(1);
 isOne.test(1); // true
 isOne.test(2); // false
 
```
Type Parameters:

T - tested object type

Parameters:

value - A value, may be null

Returns:

A new Predicate

isIn
```
@SafeVarargs
public static <T> Predicate<T> isIn(T... values)
```
Creates a Predicate that tests, if an object is equal to at least one of the specified values using Objects.equals(Object, Object) for comparison.
```
 Predicate<Integer> isIn = isIn(1, 2, 3);
 isIn.test(1); // true
 isIn.test(0); // false
 
```
Type Parameters:

T - closure over tested object types

Parameters:

values - an array of values of type T

Returns:

A new Predicate

Throws:

NullPointerException - if values is null

isNotNull

public static <T> Predicate<T> isNotNull()

Creates a Predicate that tests, if an object is not null


 Predicate<Integer> isNotNull = isNotNull();
 isNotNull.test(0);    // true
 isNotNull.test(null); // false

Type Parameters:: T - tested object type
Returns:: A new Predicate

isNull

public static <T> Predicate<T> isNull()

Creates a Predicate that tests, if an object is null


 Predicate<Integer> isNull = isNull();
 isNull.test(null); // true
 isNull.test(0);    // false

Type Parameters:: T - tested object type
Returns:: A new Predicate

noneOf

@SafeVarargs
public static <T> Predicate<T> noneOf(Predicate<T>... predicates)

A combinator that checks if none of the given predicates is satisfied.

Naturally noneOf is satisfied if the given predicates are empty.


 Predicate<Integer> isGreaterThanOne = i -> i > 1;
 Predicate<Integer> isGreaterThanTwo = i -> i > 2;
 noneOf().test(0);                                   // true
 noneOf(isGreaterThanOne, isGreaterThanTwo).test(1); // true
 noneOf(isGreaterThanOne, isGreaterThanTwo).test(2); // false

Type Parameters:: T - closure over tested object types
Parameters:: predicates - An array of predicates
Returns:: A new Predicate
Throws:: NullPointerException - if predicates is null

not

public static <T> Predicate<T> not(Predicate<? super T> predicate)

Negates a given Predicate.


 // negates a method reference
 Predicate<String> isNotNull1 = not(Objects::isNull);
 isNotNull1.test("");   // true
 isNotNull1.test(null); // false

 // negates a predicate instance
 Predicate<String> isNotNull2 = not(Predicates.isNull());
 isNotNull2.test("");   // true
 isNotNull2.test(null); // false

Type Parameters:: T - tested object type
Parameters:: predicate - A Predicate that tests elements of type T
Returns:: A new Predicate
Throws:: NullPointerException - if predicate is null

Class Predicates