author | ddmitriev |
Wed, 21 Sep 2016 16:46:13 +0300 | |
changeset 41292 | 08bd6740b8e3 |
parent 26067 | b32ccc3a76c9 |
permissions | -rw-r--r-- |
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/* |
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* Copyright (c) 2014, Oracle and/or its affiliates. All rights reserved. |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* - Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* |
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* - Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in the |
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* documentation and/or other materials provided with the distribution. |
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* |
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* - Neither the name of Oracle nor the names of its |
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* contributors may be used to endorse or promote products derived |
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* from this software without specific prior written permission. |
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8055199: Tidy up Nashorn codebase for code standards (August 2014)
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
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* IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
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* THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
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* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
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* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
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* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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*/ |
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// Usage: jjs array_mapreduce.js |
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// Many Array.prototype functions such as map, |
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// filter, reduce, reduceRight, every, some are generic. |
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// These functions accept ECMAScript array as well as |
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// many array-like objects including java arrays. |
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// So, you can do map/filter/reduce with Java streams or |
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// you can also use Array.prototype functions as below. |
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// See also http://en.wikipedia.org/wiki/MapReduce |
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var DoubleArray = Java.type("double[]"); |
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var StringArray = Java.type("java.lang.String[]"); |
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var map = Array.prototype.map; |
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var filter = Array.prototype.filter; |
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var reduce = Array.prototype.reduce; |
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var jarr = new StringArray(5); |
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jarr[0] = "nashorn"; |
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jarr[1] = "ecmascript"; |
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jarr[2] = "javascript"; |
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jarr[3] = "js"; |
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jarr[4] = "scheme"; |
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// sum of word lengths |
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print("Sum word length:", |
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reduce.call( |
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map.call(jarr, function(x) x.length), |
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function(x, y) x + y) |
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); |
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// another array example involving numbers |
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jarr = new DoubleArray(10); |
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// make random array of numbers |
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for (var i = 0; i < jarr.length; i++) |
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jarr[i] = Math.random(); |
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var forEach = Array.prototype.forEach; |
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// print numbers in the array |
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forEach.call(jarr, function(x) print(x)); |
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// print sum of squares of the random numbers |
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print("Square sum:", |
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reduce.call( |
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map.call(jarr, function(x) x*x), |
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function(x, y) x + y) |
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); |