Sean Chou wrote:
Hi,
I find there is a mismatch between the spec and the behavior of
java.io.FileOutputStream.getChannel().
The spec reads: "The initial position of the returned channel will be
equal to the number of bytes written to the file so far unless this
stream is in append mode, in which case it will be equal to the size
of the file. "
But we'll get size 0 in such situation. Here is the testcase:
//Testcase
import java.io.*;
public class FileOutputStreamTest{
public static void main(String args[]) throws Exception{
File tmpfile = File.createTempFile("FileOutputStream", "tmp");
tmpfile.deleteOnExit();
FileOutputStream fos = new FileOutputStream(tmpfile, false);
fos.write(new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 });
fos.close();
fos = new FileOutputStream(tmpfile, true);
long size = fos.getChannel().position();
if (10 != size){
// This return value is 0, mismatching the spec
System.out.println("Position Error Detected: except 10,
but was " + size);
}
fos.close();
}
}
// End of the testcase
Any comments?
This is a long standing issue, 6526860 but hasn't been high priority as
it probably isn't too common to query or change the file position when
opened for append.
-Alan.
