Question

I watched the HttpClient progress code but I still have questions I couldn’t find answer
Where to get this ProgressListener to put the constructor parameter? And how to use the code correctly? Please help

Here is the code

import java.io.FilterOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.charset.Charset;
import org.apache.http.entity.mime.HttpMultipartMode;
import org.apache.http.entity.mime.MultipartEntity;

public class CountingMultipartEntity extends MultipartEntity {

    private final ProgressListener listener;

    public CountingMultipartEntity(final ProgressListener listener) {
        super();
        this.listener = listener;
    }

    public CountingMultipartEntity(final HttpMultipartMode mode, final ProgressListener listener) {
        super(mode);
        this.listener = listener;
    }

    public CountingMultipartEntity(HttpMultipartMode mode, final String boundary,
            final Charset charset, final ProgressListener listener) {
        super(mode, boundary, charset);
        this.listener = listener;
    }

    @Override
    public void writeTo(final OutputStream outstream) throws IOException {
        super.writeTo(new CountingOutputStream(outstream, this.listener));
    }

    public static interface ProgressListener {
        void transferred(long num);
    }

    public static class CountingOutputStream extends FilterOutputStream {

        private final ProgressListener listener;
        private long transferred;

        public CountingOutputStream(final OutputStream out,
                final ProgressListener listener) {
            super(out);
            this.listener = listener;
            this.transferred = 0;
        }


        public void write(byte[] b, int off, int len) throws IOException {
            out.write(b, off, len);
            this.transferred += len;
            this.listener.transferred(this.transferred);
        }

        public void write(int b) throws IOException {
            out.write(b);
            this.transferred++;
            this.listener.transferred(this.transferred);
        }
    }
}

---

Can I implement the interface like this?

...
public static interface ProgressListener {
        void transferred(long num);
    }
    public static class Progress implements ProgressListener
    {

      public void transferred(long num) {
//            // update the progress bar or whatever else you might want to do

        }

    }
...

But how can I init the ProgressListener as for this outer class which contains HttpClient then?

CountingMultiPartEntity entity = new CountingMultiPartEntity(new ProgressListener() {

        public void transferred(long num) {
            // update the progress bar or whatever else you might want to do
        }
    });

Answer 1

You’ll need to construct an implementation of the ProgressListener interface yourself if you don’t have any classes that implement it already. For things like listeners, this is commonly done with an anonymous inner class.

CountingMultipartEntity entity = new CountingMultipartEntity(new ProgressListener() {
    @Override
    public void transferred(long num) {
        // update the progress bar or whatever else you might want to do
    }
});