Count the bytes written to file via BufferedWriter formed by GZIPOutputStream

Question

I have a BufferedWriter as shown below:

BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(
        new GZIPOutputStream( hdfs.cr         


        

Answer 1

This is similar to the response by Olaseni, but I moved the counting into the BufferedOutputStream rather than the GZIPOutputStream, and this is more robust, since def.getBytesRead() in Olaseni's answer is not available after the stream has been closed.

With the implementation below, you can supply your own AtomicLong to the constructor so that you can assign the CountingBufferedOutputStream in a try-with-resources block, but still retrieve the count after the block has exited (i.e. after the file is closed).

public static class CountingBufferedOutputStream extends BufferedOutputStream {
    private final AtomicLong bytesWritten;

    public CountingBufferedOutputStream(OutputStream out) throws IOException {
        super(out);
        this.bytesWritten = new AtomicLong();
    }

    public CountingBufferedOutputStream(OutputStream out, int bufSize) throws IOException {
        super(out, bufSize);
        this.bytesWritten = new AtomicLong();
    }

    public CountingBufferedOutputStream(OutputStream out, int bufSize, AtomicLong bytesWritten)
            throws IOException {
        super(out, bufSize);
        this.bytesWritten = bytesWritten;
    }

    @Override
    public void write(byte[] b) throws IOException {
        super.write(b);
        bytesWritten.addAndGet(b.length);
    }

    @Override
    public void write(byte[] b, int off, int len) throws IOException {
        super.write(b, off, len);
        bytesWritten.addAndGet(len);
    }

    @Override
    public synchronized void write(int b) throws IOException {
        super.write(b);
        bytesWritten.incrementAndGet();
    }

    public long getBytesWritten() {
        return bytesWritten.get();
    }
}