ProgressMonitorInputStream.java

package edu.colostate.vchill;

import javax.swing.*;
import java.io.BufferedInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * A <code>BufferedInputStream</code> that allows for easy monitoring of read progress with a <code>JProgressBar</code>.
 *
 * @author Jochen Deyke
 * @version 2007-05-24
 */
public class ProgressMonitorInputStream extends BufferedInputStream {
    protected JProgressBar progress;

    public ProgressMonitorInputStream(final InputStream in, final JProgressBar progress) {
        super(in);
        this.progress = progress;
    }

    public int read() throws IOException {
        int b = super.read();
        if (this.progress != null) progress.setValue(progress.getValue() + 1);
        return b;
    }

    public int read(final byte[] b) throws IOException {
        int numRead = super.read(b);
        if (this.progress != null) progress.setValue(progress.getValue() + numRead);
        return numRead;
    }

    public int read(final byte[] b, final int off, final int len) throws IOException {
        int numRead = super.read(b, off, len);
        if (this.progress != null) progress.setValue(progress.getValue() + numRead);
        return numRead;
    }

    public void reset() throws IOException {
        int before = in.available();
        super.reset();
        int after = in.available();
        if (this.progress != null) progress.setValue(progress.getValue() + before - after);
    }

    public long skip(final long n) throws IOException {
        long skipped = super.skip(n);
        if (this.progress != null) progress.setValue(progress.getValue() + (int) skipped);
        return skipped;
    }
}