robbypelssers

import scala.util.Random
import java.io._
val testdata = "let $values := (" + (Seq.fill(5000)(Random.nextInt(10000))).mkString(",") + ")"
val writer = new PrintWriter(new File("c:/tmp/testdata.txt" ))
writer.write(testdata)
writer.close()

robbypelssers

import java.text.Normalizer


/**
 * Problem: Characters with accents or other adornments can be encoded in several different ways in Unicode
 * However, from a user point of view if they logically mean the same, text search should make no distinction 
 * between the different notations. So it's important to store text in normalized unicode form.  Code below shows
 * how to check if text is normalized and how you can normalize it.
 **/
object NormalizationTest {

robbypelssers

return
  <groups> 
  {
    for $person in $persons/person
    group by 
    $country := $person/country,
    $gender := $person/@gender
    return 
      <group country="{$country}" gender="{$gender}">
        <averageAge>{avg($person/age)}</averageAge>

robbypelssers

let $persons :=
<persons>
  <person gender="male" country="Belgium">
    <name>Person A</name>
    <age>10</age>
  </person>
  <person gender="male" country="Netherlands">
    <name>Person B</name>
    <age>20</age>
  </person>

robbypelssers

xquery version "3.0";
declare function local:increase($nums as xs:integer*, $by as xs:integer) as xs:integer* {
    $nums ! (.  + $by)
};

let $numbers := (2,3,6,8,12,14)
let $increaseByThree := local:increase(?, 3)
let $increaseByFour := local:increase(?, 4)
return 
  <result>

robbypelssers

xquery version "3.0";

let $persons :=
<persons>
  <person gender="male">
    <country>Belgium</country>
    <name>Person A</name>
    <age>10</age>
  </person>
  <person gender="male">

robbypelssers

(:
  Below I show 2 different ways of using the filter function. Both do exactly the same but one uses 
  an inline function expression while the other uses a named function reference
:)


(:  
*********************************************************************
Example of using filter with inline function expression
*********************************************************************

robbypelssers

xquery version "3.0";

declare function local:compose($f1 as function(item()) as item(), $f2 as function(item()) as item()) 
  as function(item()) as item()   {
     function($item) as item() {
         $f2($f1($item))  
     } 
}; 

(: 5 * x - 2  :)

robbypelssers

xquery version "3.0";

declare function local:flwor(
  $ctxt as item(), 
  $find as function(item()) as item()*, 
  $predicate as function(item()) as xs:boolean,
  $orderBy as function(item()) as item()) as item()* {
    
  for $result in $find($ctxt)
  where $predicate($result)

robbypelssers

In Java you often deal with a lot of boilerplate code.  A typical example is 
opening an inputstream, using the inputstream and next closing it. But this 
simple use case takes writing quite a bit of code.Some of this boilerplate 
can be factored out by using the loan pattern, where the bank connects a 
producer and consumer and takes care of the heavy lifting.  This code can be 
further generalized using generics but for illustrating purposes it serves 
as a nice example.
**************************************************
Consumer Interface                               *
**************************************************