almost.functional

Class Predicates

java.lang.Object

almost.functional.Predicates

public final class Predicates
extends java.lang.Object

Utility operations on predicates.

Method Summary

Methods

Modifier and Type	Method and Description
static <T> Predicate<T>	and(Predicate<? super T> first, Predicate<? super T> second) Create a predicate which is a logical and of two existing predicate.
static <T> Predicate<T>	contains(java.lang.Iterable<T> iterable) Returns a predicate that that tests if an iterable contains an argument.
static <T> Predicate<T>	isEqual(T targetRef) Returns a predicate that tests if two arguments are equal according to Objects.equals(Object, Object).
static <T> Predicate<T>	negate(Predicate<? super T> predicate) Negate an existing predicate's test result.
static Predicate<java.lang.String>	notEmptyString() Predicate to check that a String is not empty, i.e.
static <T> Predicate<T>	notNull() Predicate to check that a value is not null.
static <T> Predicate<T>	or(Predicate<? super T> first, Predicate<? super T> second) Create a predicate which is a logical or of two existing predicate.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

notEmptyString

public static Predicate<java.lang.String> notEmptyString()

Predicate to check that a String is not empty, i.e. not null and contains other than whitespace characters.

Returns:

true if the tested string is not empty.

notNull

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

Predicate to check that a value is not null.

Type Parameters:

T - Type of the value

Returns:

true if the value is not null

isEqual

public static <T> Predicate<T> isEqual(T targetRef)

Returns a predicate that tests if two arguments are equal according to Objects.equals(Object, Object).

Type Parameters:

T - the type of arguments to the predicate

Parameters:

targetRef - the object reference with which to compare for equality, which may be null

Returns:

a predicate that tests if two arguments are equal according to Objects.equals(Object, Object)

contains

public static <T> Predicate<T> contains(java.lang.Iterable<T> iterable)

Returns a predicate that that tests if an iterable contains an argument.

Type Parameters:

T - the type of the argument to the predicate

Parameters:

iterable - the iterable, may not be null

Returns:

a predicate that that tests if an iterable contains an argument

negate

public static <T> Predicate<T> negate(Predicate<? super T> predicate)

Negate an existing predicate's test result.

Type Parameters:

T - type of the predicate.

Parameters:

predicate - An existing predicate.

Returns:

new predicate.

Since:

1.5

and

public static <T> Predicate<T> and(Predicate<? super T> first,
                   Predicate<? super T> second)

Create a predicate which is a logical and of two existing predicate.

Type Parameters:

T - type of the predicates

Parameters:

first - first predicate.

second - second predicate.

Returns:

resultant predicate

Since:

1.5

or

public static <T> Predicate<T> or(Predicate<? super T> first,
                  Predicate<? super T> second)

Create a predicate which is a logical or of two existing predicate.

Type Parameters:

T - type of the predicates

Parameters:

first - first predicate.

second - second predicate.

Returns:

resultant predicate

Since:

1.5