How can I recognize a special delimiter string when reading from a file of strings?

Question

I want to read strings from a file. When a certain string (><) is found, I want to start reading integers instead, and convert them to binary strings.

My program is reading the strings in and saving them in an ArrayList successfully, but it does not recognise the >< symbol and therefore the reading of the binary strings is not successful.

The Code

try {
    FileInputStream fstream = new FileInputStream(fc.getSelectedFile().getPath());
    // Get the object of DataInputStream
    DataInputStream ino = new DataInputStream(fstream);
    BufferedReader br = new BufferedReader(new InputStreamReader(ino));
    String ln;
    String str, next;
    int line, c =0;

    while ((ln = br.readLine()) != null) {
        character = ln;
        System.out.println(character);
        iname.add(ln); // arraylist that holds the strings
        if (iname.get(c).equals("><")) {
            break; // break and moves
            // on with the following while loop to start reading binary strings instead.

        }
        c++;
    }

    String s = "";
    // System.out.println("SEQUENCE of bytes");

    while ((line = ino.read()) != -1) {
        String temp = Integer.toString(line, 2);
        arrayl.add(temp);
        System.out.println("telise? oxii");
        System.out.println(line);
    }

    ino.close();

} catch (Exception exc) { }

The file I'm trying to read is for example:

 T 
 E 
 a
 v 
 X 
 L 
 A 
 . 
 x 
 "><" 
 sequence of bytes.

Where the last part is saved as bytes and in the textfile appears like that. no worries this bit works. all the strings are saved in a new line.

Is the "><" going to be in a line by itself? Because otherwise what you've written is not going to work. Are there maybe any additional characters in that line (spaces, etc.)? — Christina, Mar 18 '11 at 15:29
Can you give an example of the format you are trying to read? — Peter Lawrey, Mar 18 '11 at 15:31
@Christina yes the "><" its in a line by itself. nothing else is written in that line. — elena, Mar 18 '11 at 15:34
Always read the spec of the methods you are using. [`read()`](http://download.oracle.com/javase/6/docs/api/java/io/BufferedReader.html#read()) doesn't do what you expect it to do. Don't assume what it does just based on the return type. — Mark Peters, Mar 18 '11 at 15:38
The thing is that only the first loop is actually done. and reads all the strings and the binaries as strings too — elena, Mar 18 '11 at 15:43

Hari · Answer 1 · 2011-03-18T15:49:05.390

0

Could you not do something like:

while ((ln = br.readLine()) != null){
            character=ln;
            System.out.println(character);

            //
            // Look for magic characters >< and stop reading if found
            //

            if (character.indexOf("><") >= 0) {
               break;
            }

            iname.add(ln);
    }

This would work if you didn't want to add the magic symbol to your ArrayList. Your code sample is incomplete - if you're still having trouble you'd need to post the whole class.

edited Mar 18 '11 at 15:49

answered Mar 18 '11 at 15:30

Hari

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you meant >= 0... < 0 will break at every line except the one he needs. – amit Mar 18 '11 at 15:44
Oops. You're right. Thanks for pointing that out, it's fixed. – Hari Mar 18 '11 at 15:49

score 0 · Answer 2 · answered Mar 18 '11 at 15:30

0

< is two characters and iname.get(c) is only one character.

What u should do is test if ln equals > and then another test if the next character equals < . If both test pass then break out of the loop.

you will have to becarefull

answered Mar 18 '11 at 15:30

molleman

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score 0 · Answer 3 · answered Mar 18 '11 at 15:47

0

Use a Scanner. It allows you to specify a delimiter, and has methods for reading input tokens as String or int.

answered Mar 18 '11 at 15:47

Sam Barnum

10,559
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How can I recognize a special delimiter string when reading from a file of strings?

3 Answers3