How to read input from a file that is constantly being appended to?

Question

Hi -
My problem is simple, yet very difficult to solve. There is a log file I want to read through, that is actively being written to by another program. I want to be able to block at the eof for more input, much like a network stream can block for more input. However, nothing works.
Here is my snippet so far:
            int ch = '0';
            while( !terminate ) {
                while( (char)ch != ']' ) {
                    ch = isr.read();
                    System.out.print((char)ch);
                System.out.print("\n");
            }Terminate is just a control variable. isr is an InputStreamReader.
The way the log file works is, the end of each line is denoted by a closing box-bracket. So I figured checking for that would be easy enough. The problem with that loop is, it keeps causing my IDE to hang when it runs... It will output the log file contents, but repeatedly, infinite times. I thought the read() method blocks when there is no more input?
Is there anything else I can do to capture new appended text to this file?
I've tried InputStreamReaders and FileInputStreams as well, and they all do the same thing.
Thanks!
-Josh

Answer 1

Yes, I more or less do this. Now I simply open the BufferedReader a few bytes short of the file size (to save on memory usage) and then keep the buffer open. Then I just have the thread sleep for 500ms to not throttle the CPU through the roof. Then I merely check if the buffer does not equal null, if it doesn't, that means there is more stuff to process.
I figure half a second delay maximum is practically realtime, and it is improv enough to do what I need to do.
Thanks for the help.
-Josh