Skip Reading several Lines using BufferedReader

[Stanley Mungai]

Hi guys I am reading a text file but I do not want to read the whole of it. Is there a way I can make the Buffered Reader ignore or skip reading the lines between 57 and 88 and also the lines between 129 and 160?

Here is the code I am using

String line = "";
FileInputStream fs6 = new FileInputStream("C:/Statements/" + filenames[i]);
         BufferedReader br6 = new BufferedReader(new InputStreamReader(fs6));
while((line = br.readLine())!= null){
line = br6.readLine();
}
System.out.printIn(line)

[Campbell Ritchie]

No, I don’t think you can. You can count the lines and simply ignore those with the inappropriate numbers.

line = br.nextLine();
lineNumber++;
/* One of the few places you can actually use ; after if ;-) */
if (lineNumber >= 57 && lineNumber <=88 || lineNumber >= 129 && lineNumber <= 160); //What dreadful code style!
else
{
 ...
}

But hard-coding such numbers and ranges is very error-prone, leading to brittle code if there are any changes in the format of your file.

[Stanley Mungai]

Thank you Ritchie for that insight. The lines I want to Skip have similar content. I am wondering whether we can have a code for :
if line starts with "STATEMENT OF ACCOUNT"
then
Skip 12 lines above it.
Is there anything like that?

[Campbell Ritchie]

You could do that easily if you had the lines in a List<String>. You can simply remove the last 12 lines before adding the next line. But be very careful that you really need to remove 12 lines, not 11 or 13 sometimes.

[Stanley Mungai]

Ritchie, am very new to Java so I would not know how to do that. A sample code please?

[Jeff Verdegan]

Stanley Mungai wrote:Ritchie, am very new to Java so I would not know how to do that. A sample code please?

Look at the documentation for java.util.List, and if you can't figure anything out, google for java collecitons tutorial.

[fred rosenberger]

Stanley Mungai wrote:Ritchie, am very new to Java so I would not know how to do that. A sample code please?

We don't provide code for you here. We feel it works best when you write the code and then come back with questions about why it does or doesn't work how you expect. So, give it a shot yourself, then come back and let us know where you get stuck.

[Randall Twede]

you might want to try Campbells original suggestion first(even though i agree the style sucks) that can get it "working" then try making it better. i have compared to "starts with" before

[Winston Gutkowski]

Stanley Mungai wrote:Hi guys I am reading a text file but I do not want to read the whole of it. Is there a way I can make the Buffered Reader ignore or skip reading the lines between 57 and 88 and also the lines between 129 and 160?

Java is an Object-Oriented language, so here's a thought: create a Class that does it for you.

I suspect mine might look something like this (I've only included the basics):

public final class IgnoreLines
   extends LineNumberReader {
   private final Range[] toIngore;

   IgnoreLines(Reader r, Range... toIgnore) {
      super(r);
      this.toIgnore = toIgnore;
   }

   private boolean isVisible() {
      int lineNumber = getLineNumber();
      for (Range r : toIgnore) {
         if (r.contains(lineNumber))
           return false;
      }
      return true;
   }

   public final String readLine() {
      // I leave you to implement, but it will involve a call to isVisible()
   }
}

and there's probably several ways to improve performance as well.
I leave the Range class up to you (me, I'd probably just extend java.awt.Point and add a contains() method; but I'm lazy )

HIH

Winston

[Edit] Actually, Point is a bad choice. It's inherently unsafe. But a wrapper to a Point...