    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
    018package org.apache.commons.net.io;
    019
    020import 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 *
    036 *
    037 * @see CopyStreamEvent
    038 * @see CopyStreamAdapter
    039 * @see Util
    040 */
    041public interface CopyStreamListener extends EventListener
    042{
    043    /**
    044     * This method is invoked by a CopyStreamEvent source after copying
    045     * a block of bytes from a stream.  The CopyStreamEvent will contain
    046     * the total number of bytes transferred so far and the number of bytes
    047     * transferred in the last write.
    048     * @param event The CopyStreamEvent fired by the copying of a block of
    049     *              bytes.
    050     */
    051    void bytesTransferred(CopyStreamEvent event);
    052
    053
    054    /**
    055     * This method is not part of the JavaBeans model and is used by the
    056     * static methods in the org.apache.commons.io.Util class for efficiency.
    057     * It is invoked after a block of bytes to inform the listener of the
    058     * transfer.
    059     * @param totalBytesTransferred  The total number of bytes transferred
    060     *         so far by the copy operation.
    061     * @param bytesTransferred  The number of bytes copied by the most recent
    062     *          write.
    063     * @param streamSize The number of bytes in the stream being copied.
    064     *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
    065     *        the size is unknown.
    066     */
    067    void bytesTransferred(long totalBytesTransferred,
    068                                 int bytesTransferred,
    069                                 long streamSize);
    070}