Mercurial > jdk8-mips64-public > nashorn / file revision

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

 /*

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  *     notice, this list of conditions and the following disclaimer.

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  *   - Redistributions in binary form must reproduce the above copyright

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  *   - 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.

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  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS

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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)

 );