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     * @version $Id: CopyStreamListener.java 1088720 2011-04-04 18:52:00Z dfs $
041     */
042    public interface CopyStreamListener extends EventListener
043    {
044        /**
045         * This method is invoked by a CopyStreamEvent source after copying
046         * a block of bytes from a stream.  The CopyStreamEvent will contain
047         * the total number of bytes transferred so far and the number of bytes
048         * transferred in the last write.
049         * @param event The CopyStreamEvent fired by the copying of a block of
050         *              bytes.
051         */
052        public void bytesTransferred(CopyStreamEvent event);
053    
054    
055        /**
056         * This method is not part of the JavaBeans model and is used by the
057         * static methods in the org.apache.commons.io.Util class for efficiency.
058         * It is invoked after a block of bytes to inform the listener of the
059         * transfer.
060         * @param totalBytesTransferred  The total number of bytes transferred
061         *         so far by the copy operation.
062         * @param bytesTransferred  The number of bytes copied by the most recent
063         *          write.
064         * @param streamSize The number of bytes in the stream being copied.
065         *        This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
066         *        the size is unknown.
067         */
068        public void bytesTransferred(long totalBytesTransferred,
069                                     int bytesTransferred,
070                                     long streamSize);
071    }