package org.xbib.files.ftp;

import java.util.EventObject;

/**
 * A CopyStreamEvent is triggered after every write performed by a
 * stream copying operation.  The event stores the number of bytes
 * transferred by the write triggering the event as well as the total
 * number of bytes transferred so far by the copy operation.
 *
 * @see CopyStreamListener
 * @see CopyStreamAdapter
 * @see Util
 */
public class CopyStreamEvent extends EventObject {
    /**
     * Constant used to indicate the stream size is unknown.
     */
    public static final long UNKNOWN_STREAM_SIZE = -1;
    private static final long serialVersionUID = -964927635655051867L;
    private final int bytesTransferred;
    private final long totalBytesTransferred;
    private final long streamSize;

    /**
     * Creates a new CopyStreamEvent instance.
     *
     * @param source                The source of the event.
     * @param totalBytesTransferred The total number of bytes transferred so
     *                              far during a copy operation.
     * @param bytesTransferred      The number of bytes transferred during the
     *                              write that triggered the CopyStreamEvent.
     * @param streamSize            The number of bytes in the stream being copied.
     *                              This may be set to <code>UNKNOWN_STREAM_SIZE</code> if the
     *                              size is unknown.
     */
    public CopyStreamEvent(Object source, long totalBytesTransferred,
                           int bytesTransferred, long streamSize) {
        super(source);
        this.bytesTransferred = bytesTransferred;
        this.totalBytesTransferred = totalBytesTransferred;
        this.streamSize = streamSize;
    }

    /**
     * Returns the number of bytes transferred by the write that triggered
     * the event.
     *
     * @return The number of bytes transferred by the write that triggered
     * the vent.
     */
    public int getBytesTransferred() {
        return bytesTransferred;
    }

    /**
     * Returns the total number of bytes transferred so far by the copy
     * operation.
     *
     * @return The total number of bytes transferred so far by the copy
     * operation.
     */
    public long getTotalBytesTransferred() {
        return totalBytesTransferred;
    }

    /**
     * Returns the size of the stream being copied.
     * This may be set to <code>UNKNOWN_STREAM_SIZE</code> if the
     * size is unknown.
     *
     * @return The size of the stream being copied.
     */
    public long getStreamSize() {
        return streamSize;
    }

    /**
     */
    @Override
    public String toString() {
        return getClass().getName() + "[source=" + source
                + ", total=" + totalBytesTransferred
                + ", bytes=" + bytesTransferred
                + ", size=" + streamSize
                + "]";
    }
}
