    001    /*
    002     * Licensed to the Apache Software Foundation (ASF) under one or more
    003     * contributor license agreements.  See the NOTICE file distributed with
    004     * this work for additional information regarding copyright ownership.
    005     * The ASF licenses this file to You under the Apache License, Version 2.0
    006     * (the "License"); you may not use this file except in compliance with
    007     * the License.  You may obtain a copy of the License at
    008     *
    009     *      http://www.apache.org/licenses/LICENSE-2.0
    010     *
    011     * Unless required by applicable law or agreed to in writing, software
    012     * distributed under the License is distributed on an "AS IS" BASIS,
    013     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    014     * See the License for the specific language governing permissions and
    015     * limitations under the License.
    016     */
    017
    018    package org.apache.commons.net.io;
    019
    020    import java.util.EventListener;
    021
    022    /**
    023     * The CopyStreamListener class can accept CopyStreamEvents to keep track
    024     * of the progress of a stream copying operation.  However, it is currently
    025     * not used that way within NetComponents for performance reasons.  Rather
    026     * the bytesTransferred(long, int) method is called directly rather than
    027     * passing an event to bytesTransferred(CopyStreamEvent), saving the creation
    028     * of a CopyStreamEvent instance.  Also, the only place where
    029     * CopyStreamListener is currently used within NetComponents is in the
    030     * static methods of the uninstantiable org.apache.commons.io.Util class, which
    031     * would preclude the use of addCopyStreamListener and
    032     * removeCopyStreamListener methods.  However, future additions may use the
    033     * JavaBean event model, which is why the hooks have been included from the
    034     * beginning.
    035     * <p>
    036     * <p>
    037     * @see CopyStreamEvent
    038     * @see CopyStreamAdapter
    039     * @see Util
    040     * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
    041     * @version $Id: CopyStreamListener.java 489397 2006-12-21 16:28:51Z rwinston $
    042     */
    043    public interface CopyStreamListener extends EventListener
    044    {
    045        /**
    046         * This method is invoked by a CopyStreamEvent source after copying
    047         * a block of bytes from a stream.  The CopyStreamEvent will contain
    048         * the total number of bytes transferred so far and the number of bytes
    049         * transferred in the last write.
    050         * @param event The CopyStreamEvent fired by the copying of a block of
    051         *              bytes.
    052         */
    053        public void bytesTransferred(CopyStreamEvent event);
    054
    055
    056        /**
    057         * This method is not part of the JavaBeans model and is used by the
    058         * static methods in the org.apache.commons.io.Util class for efficiency.
    059         * It is invoked after a block of bytes to inform the listener of the
    060         * transfer.
    061         * @param totalBytesTransferred  The total number of bytes transferred
    062         *         so far by the copy operation.
    063         * @param bytesTransferred  The number of bytes copied by the most recent
    064         *          write.
    065         * @param streamSize The number of bytes in the stream being copied.
    066         *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
    067         *        the size is unknown.
    068         */
    069        public void bytesTransferred(long totalBytesTransferred,
    070                                     int bytesTransferred,
    071                                     long streamSize);
    072    }