JAVA : Statistics Class

Another name for it would be Counter class.

How many times you did this ?

int databaseUpdateCounter=0;
.
{
.
     databaseUpdateCounter++;
.
}
.
.
System.out.println( "databaseUpdateCounter"+ databaseUpdateCounter);

you only need to follow up on the count of a certain operation.

And then you needed to count something else, and kept on adding counterVariables ?!

int databaseUpdateCounter=0;

int databaseInsertCounter=0;

int databaseDeleteCounter=0;
.
{
.
databaseUpdateCounter++;
.

databaseInsertCounter++;

. . .

.

.
}
.
.
System.out.println( "databaseUpdateCounter"+ databaseUpdateCounter);

. . .

Well, That’s what  you learned OO programming for.
I’m using a Statistics Class that has an Internal HashMap and some nice methods for administrating and displaying the counters you add to it.

/*
*  This is the Stats Class
*/
package x.y.z.utils;

import java.math.BigInteger;
import java.util.Date;
import java.util.HashMap;

/**
*
* @author Ahmed Maklad
*/
public class MyStats {
private static final HashMap<String,BigInteger> statMap=new HashMap<String,BigInteger>();
private static final HashMap<String,Long> statLastUpdateMap=new HashMap<String,Long>();
private static final HashMap<String,Double> statTotalUpdateMap=new HashMap<String,Double>();
static{
//
}

    // the typical Counter++ method
public static void inc(String statKey){
BigInteger newVal;
if (statMap.containsKey(statKey)){
newVal=statMap.get(statKey).add( BigInteger.valueOf(1)) ;
}else{
newVal=BigInteger.valueOf(1);
}
set(statKey,newVal.intValue());
}

    // in-case you want to jump-start or reset the counter
public static void set(String statKey,int val){
statMap.put(statKey, BigInteger.valueOf(val) );
// Rate MyStats
double totalDuration ;
if (statLastUpdateMap.containsKey(statKey)){
totalDuration =  statLastUpdateMap.get(statKey);
totalDuration = System.currentTimeMillis() - totalDuration;
totalDuration= totalDuration+statTotalUpdateMap.get(statKey);
}else{
totalDuration = Long.valueOf(0L);
}
statTotalUpdateMap.put(statKey, totalDuration);
statLastUpdateMap.put(statKey, System.currentTimeMillis() );
}

    // get the current status of a Counter
public static int get(String statKey){
int returnVal=0;
if (statMap.containsKey(statKey)){
returnVal = statMap.get(statKey ).intValue();
}else{
set(statKey,0);
returnVal=0;
}
return returnVal;
}

    // get a report about the counters and their update rate
public static String getStats(){
StringBuilder resultText=new StringBuilder();
resultText.append ("******************* START STATISTICS **************************\n");
resultText.append ( String.format( "%-40s : %6s : %6s : %6s : %6s \n", "key","Count","ticks/sec","Total Time","Last Update") );
for (String key:statMap.keySet()){
long count;
double rate;
if (statMap.get(key).intValue()>0 ) {
count=statMap.get(key).longValue();
}else{
count=1;
}
rate= statTotalUpdateMap.get(key).longValue()  / Long.valueOf(count).doubleValue() /1000;
resultText.append (
String.format( "%-40s : %6d : %9.2f : %10.2f : %6s \n",
key,
count,
rate ,
statTotalUpdateMap.get(key)/1000,
new Date( statLastUpdateMap.get(key) ) )
);
}
resultText.append ("******************* END STATISTICS **************************");
return resultText.toString();
}
}

How to use this class in your code:

• Simply invoke MyStats.inc(“COUNTER_NAME”); and it will be added to your MyStats class.
• Since all methods are static, you don’t need to instantiate it.
• The class makes a simple calculation between each update of a counter and calculates the update rate.
• At the end of your code invoke MyStats.getStats() method to get a full report about counters and their update rates.

public boolean updateAddressDb(AddressRecord spoi){
. . .
MyStats.inc("DB_UPDATE_ADDRRECORD");
}
public boolean deleteAddressDb(AddressRecord spoi){
. . .
MyStats.inc("DB_DELETE_ADDRRECORD");
}

public boolean InsertAddressDb(AddressRecord spoi){
. . .
  try{
      MyStats.inc("DB_INSERT_ADDRRECORD");
  } catch(Exception ex){
      . . .
      MyStats.inc(ex.getMessage());
  }
}
public static void main(String [] args){
 ...
AddressRecord adr=new AddressRecord ();
. . .
 . . .
// do your Business
InsertAddressDb(adr);
. . .
updateAddressDb(adr)
. . .
deleteAddressDb(adr)
...
// get the stats
System.out.println (MyStats.getStats);
}

The output should be something like this:

******************* START STATISTICS **************************
 key                                     :  Count : ticks/sec : Total Time : Last Update
 DB_UPDATE_ADDRRECORD                    :     30 :      3.44 :     103.06 : Fri Aug 03 12:28:26 CEST 2012
 DB_INSERT_ADDRRECORD                    :     30 :      3.44 :     103.06 : Fri Aug 03 12:28:24 CEST 2012
 DB_DELETE_ADDRRECORD                    :     29 :      3.44 :     103.06 : Fri Aug 03 12:28:23 CEST 2012
 Exception Xyz                           :      1 :      1.78 :       3.56 : Fri Aug 03 12:27:04 CEST 2012
 ******************* END STATISTICS **************************

I don’t see any reason why this couldn’t be also useful in other languages like PHP and Perl … etc.
Off course there is plenty space of improvement in the class, please feel free to comment with your suggestions and improvements.

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