example
Class TakeCharsReady

java.lang.Object
  example.TakeCharsReady

public class TakeCharsReady
extends java.lang.Object

The class to demonstrate ComTest as a test and design tool. In this example we have side effect that makes the testing a bit more complex. Suppose our problem is to do some linguistic research and find what are the most popular three first vowels from every verse in Finish national poetry Kalevala. The first song of Kalevala begins like:

 Mieleni minun tekevi, aivoni ajattelevi
 lähteäni laulamahan, saa'ani sanelemahan,
 sukuvirttä suoltamahan, lajivirttä laulamahan.
 Sanat suussani sulavat, puhe'et putoelevat,
 kielelleni kerkiävät, hampahilleni hajoovat.
 

At the beginning we will need to read the file kalevala.txt and then take every verse and extract there 3 first vowels. To extract the 3 first vowels we might need a function extract3FirstVowels(s). But to make it a bit more generic we may send the number 3 as a parameter. And to make it more general we might send also the list of chars to extract as a parameter. So we need a function extractChars(s,n,letters)

Version:

8.6.2010

Author:

vesal

Constructor Summary

TakeCharsReady()

Method Summary

static java.lang.String	extractChars(java.lang.StringBuilder s, int n, java.lang.String letters) Take from s the n first chars that are in the list of letters and return them.
static void	main(java.lang.String[] args)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

TakeCharsReady

public TakeCharsReady()

Method Detail

extractChars

public static java.lang.String extractChars(java.lang.StringBuilder s,
                                            int n,
                                            java.lang.String letters)

Take from s the n first chars that are in the list of letters and return them.

Parameters:

s - where to take letters

n - how many letters to take at max

letters - set of letters we are looking

Returns:

n first chars belonging to set letters

Example:

   StringBuilder s = new StringBuilder("Mieleni minun tekevi");
   extractChars(s,3,"aeiouyåäö") === "iee"; s.toString() === "Mlni minun tekevi"; 
   extractChars(s,3,"xyz") === "";          s.toString() === "Mlni minun tekevi"; 
   extractChars(s,4,"klmn") === "Mlnm";     s.toString() === "i inun tekevi"; 
   extractChars(s,4,"e") === "ee";          s.toString() === "i inun tkvi"; 
 

,

   StringBuilder s;
   s = new StringBuilder($s);
   extractChars(s,$n,$letters) === $result; s.toString() === $left;
   
            $s              | $n | $letters    | $result  | $left
   -------------------------------------------------------------------------------  
     "Mieleni minun tekevi" |  3 | "aeiouyåäö" | "iee"    | "Mlni minun tekevi" 
     ---                    |  3 | "xyz"       | ""       | "Mlni minun tekevi" 
     ---                    |  4 | "klmn"      | "Mlnm"   | "i inun tekevi" 
     ---                    |  4 | "e"         | "ee"     | "i inun tkvi" 
 

main

public static void main(java.lang.String[] args)

Parameters:

args - not used