Re: Passing a Method Name to a Method, Redux

From:
blmblm@myrealbox.com <blmblm.myrealbox@gmail.com>
Newsgroups:
comp.lang.java.programmer
Date:
24 Jun 2011 19:19:57 GMT
Message-ID:
<96k6atFt60U2@mid.individual.net>
In article <iu129n$d0q$1@dont-email.me>, markspace <-@.> wrote:

On 6/23/2011 7:48 PM, Gene Wirchenko wrote:

On Thu, 23 Jun 2011 18:30:21 -0700, markspace<-@.> wrote:


[ snip ]

BTW I refactored your test that you were copy-and-pasting around into
one method. Using techniques I mentioned in my first post to you on
this subject.

     private static void time( TestCase r ) {
         long StartTime = System.nanoTime();
         for( int i = 1; i <= nRepetitions; i++ ) {
            r.parse();
         }
         long EndTime = System.nanoTime();
         long Duration = EndTime - StartTime;
         System.out.println( " Duration=" + (Duration/1e9) );
     }


Gene --

Below is my revision, along similar lines to what markspace suggests
above but a complete program program based on your code. I tried not
to make gratuitous additional changes, but I admit that I did move the
declaration of the loop counter into the "for" construct because, well,
*one* gratuitous change to make the program look less Java-unidiomatic?
(Also I admit I ran the whole program through vim's "reindent", but
that should change only whitespace.)

Non-whitespace changes marked "// (blmblm)".

import java.util.*;

public class TimingTesting2
{

    // (blmblm) added
    interface Searcher {
        boolean search(char CurrChar);
    }

    static String cParseString=
        "//identifier//IDENTIFIER//a_b_c abc1234b5%$__dbl;one;two;three;END";

    static String IdentChars=
        "0123456789"+
        "ABCDEFGHIJKLMNOPQRSTUVWXYZ"+
        "_"+
        "abcdefghijklmnopqrstuvwxyz"; // sorted order!

    static SortedSet<Character> IdentCharsSet=new TreeSet<Character>();

    static int nRepetitions=1000000;

    static boolean SequentialSearch
        (
         char CurrChar
        )
        {
            boolean fFound=false;
            for (int i=0; i<IdentChars.length() && !fFound; i++)
                fFound=IdentChars.charAt(i)==CurrChar;
            return fFound;
        }

    static boolean BinarySearch
        (
         char CurrChar
        )
        {
            int xLow=0;
            int xHigh=IdentChars.length()-1;
            int xTry;
            boolean fFound=false;
            while (xLow<=xHigh)
            {
                xTry=(xLow+xHigh)/2;
                if (CurrChar==IdentChars.charAt(xTry))
                    return true;
                if (CurrChar<IdentChars.charAt(xTry))
                    xHigh=xTry-1;
                else
                    xLow=xTry+1;
            }
            return false;
        }

    static boolean TreesetSearch
        (
         char CurrChar
        )
        {
            return IdentCharsSet.contains(CurrChar);
        }

    // (blmblm) merge three separate Parse routines
    static void Parse(Searcher searcher)
    {
        int xScan=0;
        boolean fBuildingIdent=false;
        boolean fInIdentChars;
        String cIdent=""; // fussy init
        while (xScan<cParseString.length())
        {
            char CurrChar=cParseString.charAt(xScan);
            fInIdentChars=SequentialSearch(CurrChar);
            if (searcher.search(CurrChar)) // (blmblm)
                if (fBuildingIdent)
                    cIdent+=CurrChar;
                else
                {
                    fBuildingIdent=true;
                    cIdent=""+CurrChar;
                }
            else
                if (fBuildingIdent)
                {
                    fBuildingIdent=false;
                    if (nRepetitions==1)
                        System.out.println(cIdent);
                }
                else
                {}
            xScan++;
        }
        if (fBuildingIdent)
            if (nRepetitions==1)
                System.out.println(cIdent);
    }

    // (blmblm) factor out common code, as suggested by markspace
    static void time(Searcher searcher) {
        long StartTime;
        long EndTime;
        long Duration;

        StartTime=System.nanoTime();
        // (blmblm) gratuitous change (declare loop counter within "for")
        for (int i=1; i<=nRepetitions; i++)
            Parse(searcher);
        EndTime=System.nanoTime();
        Duration=EndTime-StartTime;
        System.out.println(" Duration="+Duration);
    }

    public static void main(String[] args)
    {
        System.out.println("Timing Testing of Character Searching");
        System.out.println();

        // Initialise Set.
        // (blmblm) gratuitous change (declare loop counter within "for")
        for (int i=0; i<IdentChars.length(); i++)
            IdentCharsSet.add(IdentChars.charAt(i));

        // Character Sequential
        System.out.print("Character Sequential Search");
        // (blmblm) use common-code method
        time(new Searcher() {
            public boolean search(char CurrChar) {
                return SequentialSearch(CurrChar);
            }
        });

        // Character Binary Search
        System.out.print("Character Binary Search ");
        // (blmblm) use common-code method
        time(new Searcher() {
            public boolean search(char CurrChar) {
                return BinarySearch(CurrChar);
            }
        });

        // Character Treeset
        System.out.print("Character Treeset Search ");
        // (blmblm) use common-code method
        time(new Searcher() {
            public boolean search(char CurrChar) {
                return TreesetSearch(CurrChar);
            }
        });
    }

}

--
B. L. Massingill
ObDisclaimer: I don't speak for my employers; they return the favor.

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