1 /*
   2  * Copyright (c) 2012, 2013, Oracle and/or its affiliates. All rights reserved.
   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
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 package java.util.function;
  26 
  27 import java.util.Objects;
  28 
  29 /**
  30  * An operation on a single {@code int} operand yielding an {@code int} result.
  31  * This is the primitive type specialization of {@link UnaryOperator} for
  32  * {@code int}.
  33  *
  34  * @see UnaryOperator
  35  * @since 1.8
  36  */
  37 @FunctionalInterface
  38 public interface IntUnaryOperator {
  39 
  40     /**
  41      * Returns the {@code int} value result of the operation upon the
  42      * {@code int} operand.
  43      *
  44      * @param operand the operand value
  45      * @return the operation result value
  46      */
  47     int applyAsInt(int operand);
  48 
  49     /**
  50      * Compose a new function which applies the provided function followed by
  51      * this function.  If either function throws an exception, it is relayed
  52      * to the caller.
  53      *
  54      * @param before an additional function to be applied before this function
  55      * is applied
  56      * @return a function which performs the provided function followed by this
  57      * function
  58      * @throws NullPointerException if before is null
  59      */
  60     default IntUnaryOperator compose(IntUnaryOperator before) {
  61         Objects.requireNonNull(before);
  62         return (int v) -> applyAsInt(before.applyAsInt(v));
  63     }
  64 
  65     /**
  66      * Compose a new function which applies this function followed by the
  67      * provided function.  If either function throws an exception, it is relayed
  68      * to the caller.
  69      *
  70      * @param after an additional function to be applied after this function is
  71      * applied
  72      * @return a function which performs this function followed by the provided
  73      * function followed
  74      * @throws NullPointerException if after is null
  75      */
  76     default IntUnaryOperator andThen(IntUnaryOperator after) {
  77         Objects.requireNonNull(after);
  78         return (int t) -> after.applyAsInt(applyAsInt(t));
  79     }
  80 
  81     /**
  82      * Returns a unary operator that provides its input value as the result.
  83      *
  84      * @return a unary operator that provides its input value as the result
  85      */
  86     static IntUnaryOperator identity() {
  87         return t -> t;
  88     }
  89 }