nashorn/samples/jsobject_mapreduce.js
author weijun
Tue, 30 Sep 2014 13:38:58 +0800
changeset 26865 a7c2a3edbffc
parent 26067 b32ccc3a76c9
permissions -rw-r--r--
8058657: Add @jdk.Exported to com.sun.jarsigner APIs Reviewed-by: alanb, mchung

#// Usage: jjs -scripting -cp . jsobject_mapreduce.js

/*
 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
 *
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 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
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 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle nor the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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 */

// Many Array.prototype functions such as map,
// filter, reduce, reduceRight, every, some are generic.
// These functions accept ECMAScript array as well as
// many array-like objects including JSObjects.
// See also http://en.wikipedia.org/wiki/MapReduce

`javac BufferArray.java`;

var BufferArray = Java.type("BufferArray");
var buf = new BufferArray(10);

var map = Array.prototype.map;
var filter = Array.prototype.filter;
var reduce = Array.prototype.reduce;

// make random list of numbers
for (var i = 0; i < 10; i++)
    buf[i] = Math.random();

var forEach = Array.prototype.forEach;
// print numbers in the list
forEach.call(buf, function(x) print(x));

// print sum of squares of the random numbers
print("Square sum:",
    reduce.call(
        map.call(buf, function(x) x*x),
        function(x, y) x + y)
);