24283
|
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 |
|
|
42 |
var BufferArray = Java.type("BufferArray");
|
|
43 |
var buf = new BufferArray(10);
|
|
44 |
|
|
45 |
var map = Array.prototype.map;
|
|
46 |
var filter = Array.prototype.filter;
|
|
47 |
var reduce = Array.prototype.reduce;
|
|
48 |
|
|
49 |
// make random list of numbers
|
|
50 |
for (var i = 0; i < 10; i++)
|
|
51 |
buf[i] = Math.random();
|
|
52 |
|
|
53 |
var forEach = Array.prototype.forEach;
|
|
54 |
// print numbers in the list
|
|
55 |
forEach.call(buf, function(x) print(x));
|
|
56 |
|
|
57 |
// print sum of squares of the random numbers
|
|
58 |
print("Square sum:",
|
|
59 |
reduce.call(
|
|
60 |
map.call(buf, function(x) x*x),
|
|
61 |
function(x, y) x + y)
|
|
62 |
);
|