jsobject_mapreduce.js revision 802:235d22ccfd24 
1#// Usage: jjs -scripting -cp . jsobject_mapreduce.js
2
3/*
4 * Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 *   - Redistributions of source code must retain the above copyright
11 *     notice, this list of conditions and the following disclaimer.
12 *
13 *   - Redistributions in binary form must reproduce the above copyright
14 *     notice, this list of conditions and the following disclaimer in the
15 *     documentation and/or other materials provided with the distribution.
16 *
17 *   - Neither the name of Oracle nor the names of its
18 *     contributors may be used to endorse or promote products derived
19 *     from this software without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
22 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
23 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
24 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
25 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
26 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
27 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
28 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32 */
33
34// Many Array.prototype functions such as map,
35// filter, reduce, reduceRight, every, some are generic.
36// These functions accept ECMAScript array as well as
37// many array-like objects including JSObjects.
38// See also http://en.wikipedia.org/wiki/MapReduce
39
40`javac BufferArray.java`;
41
42var BufferArray = Java.type("BufferArray");
43var buf = new BufferArray(10);
44
45var map = Array.prototype.map;
46var filter = Array.prototype.filter;
47var reduce = Array.prototype.reduce;
48
49// make random list of numbers
50for (var i = 0; i < 10; i++)
51    buf[i] = Math.random();
52
53var forEach = Array.prototype.forEach;
54// print numbers in the list
55forEach.call(buf, function(x) print(x));
56
57// print sum of squares of the random numbers
58print("Square sum:",
59    reduce.call(
60        map.call(buf, function(x) x*x),
61        function(x, y) x + y)
62);
63