    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 of the progress of a stream copying operation. However, it is currently not used that
    024 * way within NetComponents for performance reasons. Rather the bytesTransferred(long, int) method is called directly rather than passing an event to
    025 * bytesTransferred(CopyStreamEvent), saving the creation of a CopyStreamEvent instance. Also, the only place where CopyStreamListener is currently used within
    026 * NetComponents is in the static methods of the uninstantiable org.apache.commons.io.Util class, which would preclude the use of addCopyStreamListener and
    027 * removeCopyStreamListener methods. However, future additions may use the JavaBean event model, which is why the hooks have been included from the beginning.
    028 *
    029 *
    030 * @see CopyStreamEvent
    031 * @see CopyStreamAdapter
    032 * @see Util
    033 */
    034public interface CopyStreamListener extends EventListener {
    035    /**
    036     * This method is invoked by a CopyStreamEvent source after copying a block of bytes from a stream. The CopyStreamEvent will contain the total number of
    037     * bytes transferred so far and the number of bytes transferred in the last write.
    038     *
    039     * @param event The CopyStreamEvent fired by the copying of a block of bytes.
    040     */
    041    void bytesTransferred(CopyStreamEvent event);
    042
    043    /**
    044     * This method is not part of the JavaBeans model and is used by the static methods in the org.apache.commons.io.Util class for efficiency. It is invoked
    045     * after a block of bytes to inform the listener of the transfer.
    046     *
    047     * @param totalBytesTransferred The total number of bytes transferred so far by the copy operation.
    048     * @param bytesTransferred      The number of bytes copied by the most recent write.
    049     * @param streamSize            The number of bytes in the stream being copied. This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if the size is
    050     *                              unknown.
    051     */
    052    void bytesTransferred(long totalBytesTransferred, int bytesTransferred, long streamSize);
    053}