String Tokenizer Problem

[Anne Buena]

Hi! I have some confusion with StringTokenizer. I have this line of text in file:

1012012*8:00*12:00*

The problem is this file is being updated. For short, the number of tokens is unknown because it is updated always.
What code should I use? Do I need to use array or what?

Thank you for the response

[Stephan van Hulst]

We can't really give you an answer. What's the format of the data? How will it be updated? What information do you want to extract? In short, TellTheDetails.

I can already give you one tip. Don't use StringTokenizer. It's obsolete. Use a Scanner instead.

[Anne Buena]

The data is int.

1012012*8:00*12:00*

I want to get the first token then the second and so on for computation. My only problem is that I don't know what action should I do if the number of tokens are not defined or unknown.

Thank you for that tip. What should be my algorithm/steps for scanner?

[Stephan van Hulst]

Obviously the format is not int, because there are characters like '*' and ':'. How should we deal with them?

Anyway, if you know how to delimit the input, then you can create a Scanner instance on the input, and set the delimiter. Then all you have to do is perform a while loop in which you check Scanner.hasNextInt() and in the body you read Scanner.nextInt().

[Campbell Ritchie]

Anne Buena wrote:The data is int. . . .

No, it isn’t. I can see no way to get an int out of that expression, not even if : means divide. That is a String with various numbers in. It should be easy enough to work out a regular expression for, but beware ^ is a meta-character in regular expressions.

[Saurabh Pillai]

Stephan van Hulst wrote:Don't use StringTokenizer. It's obsolete. Use a Scanner instead.

... or String.split() method.

[Stephan van Hulst]

I think it would be pretty cumbersome to load an entire file into a String before working on it

[Saurabh Pillai]

Stephan van Hulst wrote:I think it would be pretty cumbersome to load an entire file into a String before working on it

Actually, I read the text file line by line (using BufferedReader & FileReader) in while loop and split contents of each line using split method. I have not tried Scanner yet.

[Campbell Ritchie]

A Scanner only works on a text file. It is easier than a buffered reader. If you click the link on the top line, you will find code similar to this:

import java.io.File;
import java.util.List;
import java.util.Scanner;
 . . .
List<Integer> myList = new ???List<>(); // Diamond only works in Java7
try (Scanner inScan = new Scanner(new File("myfile.txct")) // Look up try-with-resources. Only works in Java7
{
   inScan.useDelimiter("RegularExpressionFor ^:");
   while(inScan.hasNextInt())
   {
       myList.add(inScan.nextInt());
   }
}
catch (java.io.fileNotFoundException fnf)
{
   ...
}