CODEWITHSUNDEEP
java
A D
A D

Reputation: 79

Count transactions per second from timestamp with java

I have an arraylist filled with timestamps (up to millisec)

2015/11/01 12.12.12.990
2015/11/01 12.12.12.992
2015/11/01 12.12.12.999

2015/11/01 12.12.15.135
2015/11/01 12.12.15.995

2015/11/01 12.12.20.135
2015/11/01 12.12.20.200
2015/11/01 12.12.20.300
2015/11/01 12.12.20.900

Each timestamp is a transaction and I need to calculate tps. How do I get a list of list which eventually it would be something like this

2015/11/01 12.12.12, 3
2015/11/01 12.12.12, 2
2015/11/01 12.12.20, 4

where first is the timestamps occurred for one second on second level and 3,2,4 etc is the tps?

Upvotes: 0

Views: 2176

Answers (2)

Shivam
Shivam

Reputation: 649

You have to use one ArrayList to contain all the timestamps and one new HashMap with a String as a key and an Integer as a value where the String contains timestamps and the Integer is a counter. like this;

HashMap<String, Integer> hash = new HashMap<>();

Then you have to insert the timestamp and count values in the hashmap using a for loop after comparing the previous values with current value of the ArrayList, like this:

if(i>0 && al.get(i).substring(0, 19).equalsIgnoreCase(al.get(i-1).substring(0, 19)))
hash.put(al.get(i).substring(0, 19),count);

Then the key values you have in the hashmap are the results. The code is:

ArrayList<String> al = new ArrayList<String>();
    al.add("2015/11/01 12.12.12.990");
    al.add("2015/11/01 12.12.12.992");
    al.add("2015/11/01 12.12.12.999");
    al.add("2015/11/01 12.12.15.135");
    al.add("2015/11/01 12.12.15.995");
    al.add("2015/11/01 12.12.20.135");
    al.add("2015/11/01 12.12.20.200");
    al.add("2015/11/01 12.12.20.300");
    al.add("2015/11/01 12.12.20.900");

    HashMap<String, Integer> hash = new HashMap<>();
    int count = 0;
    for(int i=0;i<al.size();i++){
        if(i>0 && al.get(i).substring(0, 19).equalsIgnoreCase(al.get(i-1).substring(0, 19)))
            hash.put(al.get(i).substring(0, 19),++count);
        else
            hash.put(al.get(i).substring(0, 19),count=1);
    }
    for (Entry<String, Integer> entry : hash.entrySet()) {
        System.out.println(entry.getKey()+","+entry.getValue());
    }

Upvotes: 1

Tim B
Tim B

Reputation: 41188

Create a class looking something like:

public class TransactionsPerSecond {
    long time;
    int transactions=1; //Start at 1 to count the initial one
}

Loop through the incoming data. If the time doesn't match the current TransactionsPerSecond object then create a new one, otherwise add 1 to the transactions count for the current one.

// For you to do, create results arraylist.

TransactionsPerSecond current = null;

for (String str: inputData) {

   // for you to do - parse str into a Date d.
   Date d = ???;

   if (current == null || d.getTime() != current.time) {
      current = new TransactionsPerSecond();
      current.time = d.getTime();
      results.add(current);
   } else {
      current.transactions++;
   }
}

Upvotes: 1

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