ProgressReportingInputStream.java

package bndtools.utils;

import java.io.IOException;
import java.io.InputStream;

import org.eclipse.core.runtime.IProgressMonitor;

public class ProgressReportingInputStream extends InputStream {

    private final InputStream stream;
    private final IProgressMonitor monitor;

    /**
     * Wrap an existing input stream with a progress-reporting input stream. Subsequently reading data from the wrapped
     * stream will cause progress to be shown on the supplied progress monitor. NB: It is the caller's responsibility to
     * call the {@code beginTask()} method of the progress monitor BEFORE any of the stream methods (e.g.
     * {@code #read()} etc) are accessed.
     * 
     * @param stream
     * @param monitor
     */
    public ProgressReportingInputStream(InputStream stream, IProgressMonitor monitor) {
        this.stream = stream;
        this.monitor = monitor;
    }

    @Override
    public int read() throws IOException {
        int result = stream.read();
        if (result > 0)
            monitor.worked(1);
        return result;
    }

    @Override
    public int read(byte[] b) throws IOException {
        int result = stream.read(b);
        if (result > 0)
            monitor.worked(result);
        return result;
    }

    @Override
    public int read(byte[] b, int off, int len) throws IOException {
        int result = stream.read(b, off, len);
        if (result > 0)
            monitor.worked(result);
        return result;
    }

    @Override
    public long skip(long n) throws IOException {
        long result = stream.skip(n);
        if (result > 0)
            monitor.worked((int) result);
        return result;
    }

    @Override
    public int available() throws IOException {
        return stream.available();
    }

    @Override
    public void close() throws IOException {
        stream.close();
        monitor.done();
    }

    @Override
    public synchronized void mark(int readlimit) {
        stream.mark(readlimit);
    }

    @Override
    public synchronized void reset() throws IOException {
        stream.reset();
    }

    @Override
    public boolean markSupported() {
        return stream.markSupported();
    }

}