io.github.jonestimd.util.JavaPredicates Maven / Gradle / Ivy
// The MIT License (MIT)
//
// Copyright (c) 2017 Timothy D. Jones
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// SOFTWARE.
package io.github.jonestimd.util;
import java.util.function.Function;
import java.util.function.Predicate;
/**
* Utility methods for predicates.
*/
public class JavaPredicates {
/**
* Chain a function and a predicate. Useful for combining method references.
*/
public static Predicate onResult(Function function, Predicate predicate) {
return input -> predicate.test(function.apply(input));
}
/**
* Invert the result of a predicate.
*/
public static Predicate not(Predicate methodRef) {
return methodRef.negate();
}
/**
* Return a predicate that always returns true.
*/
public static Predicate alwaysTrue() {
return (input) -> true;
}
/**
* Return a predicate that always returns false.
*/
public static Predicate alwaysFalse() {
return (input) -> false;
}
}