/*+
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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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 *+
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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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+
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// Usage: jjs list_mapreduce.js+
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+
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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.util.ArrayLists.+
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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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+
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var ArrayList = Java.type("java.util.ArrayList");+
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var list = new ArrayList();+
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list.add("nashorn");+
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list.add("ecmascript");+
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list.add("javascript");+
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list.add("js");+
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list.add("scheme");+
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+
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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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+
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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(list, function(x) x.length),+
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        function(x, y) x + y)+
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);+
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+
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// filter use to filter out "j*" and concatenate rest with ":"+
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// after uppercasing all strings+
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print(+
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    reduce.call(+
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        map.call(+
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            filter.call(list, function(x) !x.startsWith("j")),+
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            function(x) x.toUpperCase()),+
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        function(x, y) x + ":" + y)+
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);+
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+
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// another list example involving numbers+
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list.clear();+
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// make random list of numbers+
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for (var i = 0; i < 10; i++)+
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    list.add(Math.random());+
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+
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var forEach = Array.prototype.forEach;+
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// print numbers in the list+
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forEach.call(list, function(x) print(x));+
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+
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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(list, function(x) x*x),+
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        function(x, y) x + y)+
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);+
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