Name: nt126004 Date: 06/25/2002


FULL PRODUCT VERSION :
C:\>java -version
java version "1.4.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.0-b92)
Java HotSpot(TM) Client VM (build 1.4.0-b92, mixed mode)

FULL OPERATING SYSTEM VERSION :

Microsoft Windows 2000 [Version 5.00.2195]

A DESCRIPTION OF THE PROBLEM :
In RandomAccessFile in the java.io package or FileChannel
class in the java.nio.channels package there is no facility
by which I can truncate the file beginning from the start.
The trimming of the file by giving a lower size to the
RandomAccessFile's setLength() or FileChannel's truncate()
always does truncate from the end.

But if I have a time series of data I want to be able to
easily drop the first line of data and add another at the
end. If it's provided in the API itself it would be cool.
For example a boolean switch, to truncate from end or from
the beginning.

Thanks

This bug can be reproduced often.

---------- BEGIN SOURCE ----------
public class Test {

public static void main(String [] args) {
RandomAccessFile raf = null;
        try
        {
raf = new RandomAccessFile("C:\\temp.txt","rw"); // ---
> Hardcode any file you have
long lengthOfFile = raf.length();
if(lengthOfFile != 0) {

raf.seek(0L);
raf.readLine(); // ---> I want to delete this
first line from input
long getCurrentPointer = raf.getFilePointer();
long offset = lengthOfFile - getCurrentPointer;

System.err.println("Length == '"+lengthOfFile+"'");
System.err.println("Offset == '"+getCurrentPointer+"'");
System.err.println("New Length == '"+offset+"'");
raf.setLength(offset);
raf.seek(raf.length());
}
}
catch(Exception e) {
e.printStackTrace();
}
finally {
try {
raf.close();
}
catch(Exception e) {
}
}

}
}
---------- END SOURCE ----------

CUSTOMER WORKAROUND :
Just code around this.
(Review ID: 147171)
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