Package io.vavr
Class Predicates
- java.lang.Object
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- io.vavr.Predicates
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public final class Predicates extends java.lang.Object
Defines general-purpose predicates which are particularly useful when working withAPI.Match
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Constructor Summary
Constructors Modifier Constructor Description private
Predicates()
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Method Summary
All Methods Static Methods Concrete Methods Modifier and Type Method Description static <T> java.util.function.Predicate<T>
allOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if all of the givenpredicates
are satisfied.static <T> java.util.function.Predicate<T>
anyOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if at least one of the givenpredicates
is satisfies.static <T> java.util.function.Predicate<java.lang.Iterable<T>>
exists(java.util.function.Predicate<? super T> predicate)
A combinator that checks if one or more elements of anIterable
satisfy thepredicate
.static <T> java.util.function.Predicate<java.lang.Iterable<T>>
forAll(java.util.function.Predicate<? super T> predicate)
A combinator that checks if all elements of anIterable
satisfy thepredicate
.static <T> java.util.function.Predicate<T>
instanceOf(java.lang.Class<? extends T> type)
Creates aPredicate
that tests, if an object is instance of the specifiedtype
.static <T> java.util.function.Predicate<T>
is(T value)
Creates aPredicate
that tests, if an object is equal to the specifiedvalue
usingObjects.equals(Object, Object)
for comparison.static <T> java.util.function.Predicate<T>
isIn(T... values)
Creates aPredicate
that tests, if an object is equal to at least one of the specifiedvalues
usingObjects.equals(Object, Object)
for comparison.static <T> java.util.function.Predicate<T>
isNotNull()
Creates aPredicate
that tests, if an object is not nullstatic <T> java.util.function.Predicate<T>
isNull()
Creates aPredicate
that tests, if an object is nullstatic <T> java.util.function.Predicate<T>
noneOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if none of the givenpredicates
is satisfied.static <T> java.util.function.Predicate<T>
not(java.util.function.Predicate<? super T> predicate)
Negates a givenPredicate
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Method Detail
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allOf
@SafeVarargs public static <T> java.util.function.Predicate<T> allOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if all of the givenpredicates
are satisfied.By definition
allOf
is satisfied if the givenpredicates
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:
java.lang.NullPointerException
- ifpredicates
is null
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anyOf
@SafeVarargs public static <T> java.util.function.Predicate<T> anyOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if at least one of the givenpredicates
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:
java.lang.NullPointerException
- ifpredicates
is null
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exists
public static <T> java.util.function.Predicate<java.lang.Iterable<T>> exists(java.util.function.Predicate<? super T> predicate)
A combinator that checks if one or more elements of anIterable
satisfy thepredicate
.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
- APredicate
that tests elements of typeT
- Returns:
- A new
Predicate
- Throws:
java.lang.NullPointerException
- ifpredicate
is null
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forAll
public static <T> java.util.function.Predicate<java.lang.Iterable<T>> forAll(java.util.function.Predicate<? super T> predicate)
A combinator that checks if all elements of anIterable
satisfy thepredicate
.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
- APredicate
that tests elements of typeT
- Returns:
- A new
Predicate
- Throws:
java.lang.NullPointerException
- ifpredicate
is null
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instanceOf
@GwtIncompatible public static <T> java.util.function.Predicate<T> instanceOf(java.lang.Class<? extends T> type)
Creates aPredicate
that tests, if an object is instance of the specifiedtype
.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:
java.lang.NullPointerException
- iftype
is null
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is
public static <T> java.util.function.Predicate<T> is(T value)
Creates aPredicate
that tests, if an object is equal to the specifiedvalue
usingObjects.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
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isIn
@SafeVarargs public static <T> java.util.function.Predicate<T> isIn(T... values)
Creates aPredicate
that tests, if an object is equal to at least one of the specifiedvalues
usingObjects.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:
java.lang.NullPointerException
- ifvalues
is null
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isNotNull
public static <T> java.util.function.Predicate<T> isNotNull()
Creates aPredicate
that tests, if an object is not nullPredicate<Integer> isNotNull = isNotNull(); isNotNull.test(0); // true isNotNull.test(null); // false
- Type Parameters:
T
- tested object type- Returns:
- A new
Predicate
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isNull
public static <T> java.util.function.Predicate<T> isNull()
Creates aPredicate
that tests, if an object is nullPredicate<Integer> isNull = isNull(); isNull.test(null); // true isNull.test(0); // false
- Type Parameters:
T
- tested object type- Returns:
- A new
Predicate
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noneOf
@SafeVarargs public static <T> java.util.function.Predicate<T> noneOf(java.util.function.Predicate<T>... predicates)
A combinator that checks if none of the givenpredicates
is satisfied.Naturally
noneOf
is satisfied if the givenpredicates
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:
java.lang.NullPointerException
- ifpredicates
is null
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not
public static <T> java.util.function.Predicate<T> not(java.util.function.Predicate<? super T> predicate)
Negates a givenPredicate
.// 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
- APredicate
that tests elements of typeT
- Returns:
- A new
Predicate
- Throws:
java.lang.NullPointerException
- ifpredicate
is null
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