jdk/src/share/classes/java/util/function/DoublePredicate.java

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package java.util.function;

import java.util.Objects;

/**
 * Determines if the {@code double} input value matches some criteria. This is
 * the {@code double}-consuming primitive type specialization of
 * {@link Predicate}.
 *
 * @see Predicate
 * @since 1.8
 */
@FunctionalInterface
public interface DoublePredicate {

    /**
     * Returns {@code true} if the input value matches some criteria.
     *
     * @param value the value to be tested.
     * @return {@code true} if the input value matches some criteria, otherwise
     * {@code false}.
     */
    public boolean test(double value);

    /**
     * Returns a predicate which evaluates to {@code true} only if this
     * predicate and the provided predicate both evaluate to {@code true}. If
     * this predicate returns {@code false} then the remaining predicate is not
     * evaluated.
     *
     * @param p a predicate which will be logically-ANDed with this predicate.
     * @return a new predicate which returns {@code true} only if both
     * predicates return {@code true}.
     */
    public default DoublePredicate and(DoublePredicate p) {
        Objects.requireNonNull(p);
        return (value) -> test(value) && p.test(value);
    }

    /**
     * Returns a predicate which negates the result of this predicate.
     *
     * @return a new predicate who's result is always the opposite of this
     * predicate.
     */
    public default DoublePredicate negate() {
        return (value) -> !test(value);
    }

    /**
     * Returns a predicate which evaluates to {@code true} if either this
     * predicate or the provided predicate evaluates to {@code true}. If this
     * predicate returns {@code true} then the remaining predicate is not
     * evaluated.
     *
     * @param p a predicate which will be logically-ANDed with this predicate.
     * @return a new predicate which returns {@code true} if either predicate
     * returns {@code true}.
     */
    public default DoublePredicate or(DoublePredicate p) {
        Objects.requireNonNull(p);
        return (value) -> test(value) || p.test(value);
    }

    /**
     * Returns a predicate that evaluates to {@code true} if both or neither of
     * the component predicates evaluate to {@code true}.
     *
     * @param p a predicate which will be logically-XORed with this predicate.
     * @return a predicate that evaluates to {@code true} if all or none of the
     * component predicates evaluate to {@code true}.
     */
    public default DoublePredicate xor(DoublePredicate p) {
        Objects.requireNonNull(p);
        return (value) -> test(value) ^ p.test(value);
    }
}