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 );