001 /*
002 * Copyright 2001-2005 The Apache Software Foundation
003 *
004 * Licensed under the Apache License, Version 2.0 (the "License");
005 * you may not use this file except in compliance with the License.
006 * You may obtain a copy of the License at
007 *
008 * http://www.apache.org/licenses/LICENSE-2.0
009 *
010 * Unless required by applicable law or agreed to in writing, software
011 * distributed under the License is distributed on an "AS IS" BASIS,
012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
013 * See the License for the specific language governing permissions and
014 * limitations under the License.
015 */
016 package org.apache.commons.net.io;
017
018 import java.util.EventListener;
019
020 /**
021 * The CopyStreamListener class can accept CopyStreamEvents to keep track
022 * of the progress of a stream copying operation. However, it is currently
023 * not used that way within NetComponents for performance reasons. Rather
024 * the bytesTransferred(long, int) method is called directly rather than
025 * passing an event to bytesTransferred(CopyStreamEvent), saving the creation
026 * of a CopyStreamEvent instance. Also, the only place where
027 * CopyStreamListener is currently used within NetComponents is in the
028 * static methods of the uninstantiable org.apache.commons.io.Util class, which
029 * would preclude the use of addCopyStreamListener and
030 * removeCopyStreamListener methods. However, future additions may use the
031 * JavaBean event model, which is why the hooks have been included from the
032 * beginning.
033 * <p>
034 * <p>
035 * @see CopyStreamEvent
036 * @see CopyStreamAdapter
037 * @see Util
038 * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
039 * @version $Id: CopyStreamListener.java 165675 2005-05-02 20:09:55Z rwinston $
040 */
041 public 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 public 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 public void bytesTransferred(long totalBytesTransferred,
068 int bytesTransferred,
069 long streamSize);
070 }