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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * particular file as subject to the "Classpath" exception as provided

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 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

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package java.util.function;

import java.util.Objects;

/**

 * Represents an operation on a single {@code long}-valued operand that produces

 * a {@code long}-valued result.  This is the primitive type specialization of

 * {@link UnaryOperator} for {@code long}.

 *

 * <p>This is a <a href="package-summary.html">functional interface</a>

 * whose functional method is {@link #applyAsLong(long)}.

 *

 * @see UnaryOperator

 * @since 1.8

 */

@FunctionalInterface

public interface LongUnaryOperator {

    /**

     * Applies this operator to the given operand.

     *

     * @param operand the operand

     * @return the operator result

     */

    long applyAsLong(long operand);

    /**

     * Returns a composed operator that first applies the {@code before}

     * operator to its input, and then applies this operator to the result.

     * If evaluation of either operator throws an exception, it is relayed to

     * the caller of the composed operator.

     *

     * @param before the operator to apply before this operator is applied

     * @return a composed operator that first applies the {@code before}

     * operator and then applies this operator

     * @throws NullPointerException if before is null

     *

     * @see #andThen(LongUnaryOperator)

     */

    default LongUnaryOperator compose(LongUnaryOperator before) {

        Objects.requireNonNull(before);

        return (long v) -> applyAsLong(before.applyAsLong(v));

    }

    /**

     * Returns a composed operator that first applies this operator to

     * its input, and then applies the {@code after} operator to the result.

     * If evaluation of either operator throws an exception, it is relayed to

     * the caller of the composed operator.

     *

     * @param after the operator to apply after this operator is applied

     * @return a composed operator that first applies this operator and then

     * applies the {@code after} operator

     * @throws NullPointerException if after is null

     *

     * @see #compose(LongUnaryOperator)

     */

    default LongUnaryOperator andThen(LongUnaryOperator after) {

        Objects.requireNonNull(after);

        return (long t) -> after.applyAsLong(applyAsLong(t));

    }

    /**

     * Returns a unary operator that always returns its input argument.

     *

     * @return a unary operator that always returns its input argument

     */

    static LongUnaryOperator identity() {

        return t -> t;

    }

}