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package org.omnifaces.utils.function;

import static java.util.Comparator.naturalOrder;

import java.util.Comparator;
import java.util.Objects;
import java.util.function.Function;
import java.util.function.Predicate;

import org.omnifaces.utils.Lang;

public final class Predicates {

	private Predicates() {
	}

	public static  Predicate always() {
		return t -> true;
	}

	public static  Predicate never() {
		return t -> false;
	}

	public static  Predicate isEmpty() {
		return Lang::isEmpty;
	}

	public static  Predicate isNotEmpty() {
		return Predicates.isEmpty().negate();
	}

	public static  Predicate isNull() {
		return t -> t == null;
	}

	public static  Predicate isNotNull() {
		return t -> t != null;
	}

	public static > Predicate isLessThan(T value) {
		return isLessThan(value, naturalOrder());
	}

	public static  Predicate isLessThan(T value, Comparator comparator) {
		Objects.requireNonNull(value);
		Objects.requireNonNull(comparator);

		return t -> comparator.compare(t, value) < 0;
	}

	public static > Predicate isLessThanOrEqual(T value) {
		return isLessThanOrEqual(value, naturalOrder());
	}

	public static  Predicate isLessThanOrEqual(T value, Comparator comparator) {
		Objects.requireNonNull(value);
		Objects.requireNonNull(comparator);

		return t -> comparator.compare(t, value) <= 0;
	}

	public static > Predicate isComparativelyEqualTo(T value) {
		return isComparativelyEqualTo(value, naturalOrder());
	}

	public static > Predicate isComparativelyEqualTo(T value, Comparator comparator) {
		Objects.requireNonNull(value);
		Objects.requireNonNull(comparator);

		return t -> comparator.compare(t, value) == 0;
	}

	public static > Predicate isGreaterThan(T value) {
		return isGreaterThan(value, naturalOrder());
	}

	public static  Predicate isGreaterThan(T value, Comparator comparator) {
		Objects.requireNonNull(value);
		Objects.requireNonNull(comparator);

		return t -> comparator.compare(t, value) > 0;
	}

	public static > Predicate isGreaterThanOrEqual(T value) {
		return isGreaterThanOrEqual(value, naturalOrder());
	}

	public static  Predicate isGreaterThanOrEqual(T value, Comparator comparator) {
		Objects.requireNonNull(value);
		Objects.requireNonNull(comparator);

		return t -> comparator.compare(t, value) >= 0;
	}

	public static  Predicate mapped(Function function, Predicate predicate) {
		return t -> predicate.test(function.apply(t));
	}
}