    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 *      https://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 */
    017package org.apache.commons.net.io;
    018
    019import java.util.EventListener;
    020
    021/**
    022 * Accepts {@link CopyStreamEvent}s to track the progress of a stream copying operation. However, it is currently not used that way within Net for performance
    023 * reasons. Rather, the bytesTransferred(long, int) method is called directly rather than passing an event to bytesTransferred(CopyStreamEvent), saving the
    024 * creation of a CopyStreamEvent instance. Also, the only place where CopyStreamListener is currently used within Net is in the static methods of the
    025 * uninstantiable org.apache.commons.io.Util class, which would preclude the use of addCopyStreamListener and removeCopyStreamListener methods. However, future
    026 * additions may use the JavaBean event model, which is why the hooks have been included from the beginning.
    027 *
    028 * @see CopyStreamEvent
    029 * @see CopyStreamAdapter
    030 * @see Util
    031 */
    032public interface CopyStreamListener extends EventListener {
    033    /**
    034     * Accepts a source event after copying a block of bytes from a stream. The CopyStreamEvent will contain the total number of bytes transferred so far and
    035     * the number of bytes transferred in the last write.
    036     *
    037     * @param event The CopyStreamEvent fired by the copying of a block of bytes.
    038     */
    039    void bytesTransferred(CopyStreamEvent event);
    040
    041    /**
    042     * 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
    043     * after a block of bytes to inform the listener of the transfer.
    044     *
    045     * @param totalBytesTransferred The total number of bytes transferred so far by the copy operation.
    046     * @param bytesTransferred      The number of bytes copied by the most recent write.
    047     * @param streamSize            The number of bytes in the stream being copied. This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if the size is
    048     *                              unknown.
    049     */
    050    void bytesTransferred(long totalBytesTransferred, int bytesTransferred, long streamSize);
    051}