1 /*
   2  * Copyright (c) 2012, 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 /**
  28  * Apply a function to the input object yielding an appropriate {@code double}
  29  * value; this is the {@code double}-bearing specialization for
  30  * {@link Function}.
  31  *
  32  * @param <T> the type of input objects to the {@code apply} operation.
  33  *
  34  * @since 1.8
  35  */
  36 public interface DoubleFunction<T> /* extends Function<T,Double> */ {
  37 //
  38 //    /**
  39 //     * Apply a function to the input object yielding an appropriate
  40 //     * {@code Double}.
  41 //     *
  42 //     * @param t the input object to the function
  43 //     * @return the function output {@code Double}
  44 //     */
  45 //    @Override
  46 //    public default Double apply(T t) { return applyAsDouble(t); }
  47 
  48     /**
  49      * Apply a function to the input object yielding an appropriate
  50      * {@code double} value.
  51      *
  52      * @param t the input object to the function
  53      * @return the function output value
  54      */
  55     public double applyAsDouble(T t);
  56 }