1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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  23  * questions.
  24  */
  25 package java.util.function;
  26 
  27 import java.util.Objects;
  28 
  29 /**
  30  * Represents an operation on a single {@code int}-valued operand that produces
  31  * an {@code int}-valued result.  This is the primitive type specialization of
  32  * {@link UnaryOperator} for {@code int}.
  33  *
  34  * <p>This is a <a href="package-summary.html">functional interface</a>
  35  * whose functional method is {@link #applyAsInt(int)}.
  36  *
  37  * @see UnaryOperator
  38  * @since 1.8
  39  */
  40 @FunctionalInterface
  41 public interface IntUnaryOperator {
  42 
  43     /**
  44      * Applies this operator to the given operand.
  45      *
  46      * @param operand the operand
  47      * @return the operator result
  48      */
  49     int applyAsInt(int operand);
  50 
  51     /**
  52      * Returns a composed operator that first applies the {@code before}
  53      * operator to its input, and then applies this operator to the result.
  54      * If evaluation of either operator throws an exception, it is relayed to
  55      * the caller of the composed operator.
  56      *
  57      * @param before the operator to apply before this operator is applied
  58      * @return a composed operator that first applies the {@code before}
  59      * operator and then applies this operator
  60      * @throws NullPointerException if before is null
  61      *
  62      * @see #andThen(IntUnaryOperator)
  63      */
  64     default IntUnaryOperator compose(IntUnaryOperator before) {
  65         Objects.requireNonNull(before);
  66         return (int v) -> applyAsInt(before.applyAsInt(v));
  67     }
  68 
  69     /**
  70      * Returns a composed operator that first applies this operator to
  71      * its input, and then applies the {@code after} operator to the result.
  72      * If evaluation of either operator throws an exception, it is relayed to
  73      * the caller of the composed operator.
  74      *
  75      * @param after the operator to apply after this operator is applied
  76      * @return a composed operator that first applies this operator and then
  77      * applies the {@code after} operator
  78      * @throws NullPointerException if after is null
  79      *
  80      * @see #compose(IntUnaryOperator)
  81      */
  82     default IntUnaryOperator andThen(IntUnaryOperator after) {
  83         Objects.requireNonNull(after);
  84         return (int t) -> after.applyAsInt(applyAsInt(t));
  85     }
  86 
  87     /**
  88      * Returns a unary operator that always returns its input argument.
  89      *
  90      * @return a unary operator that always returns its input argument
  91      */
  92     static IntUnaryOperator identity() {
  93         return t -> t;
  94     }
  95 }