1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache License, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the License for the specific language governing permissions and 15 * limitations under the License. 16 */ 17 18 package org.apache.commons.net.io; 19 20 import java.util.EventListener; 21 22 import org.apache.commons.net.util.ListenerList; 23 24 /** 25 * The CopyStreamAdapter will relay CopyStreamEvents to a list of listeners 26 * when either of its bytesTransferred() methods are called. Its purpose 27 * is to facilitate the notification of the progress of a copy operation 28 * performed by one of the static copyStream() methods in 29 * org.apache.commons.io.Util to multiple listeners. The static 30 * copyStream() methods invoke the 31 * bytesTransfered(long, int) of a CopyStreamListener for performance 32 * reasons and also because multiple listeners cannot be registered given 33 * that the methods are static. 34 * <p> 35 * <p> 36 * @see CopyStreamEvent 37 * @see CopyStreamListener 38 * @see Util 39 * @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a> 40 * @version $Id: CopyStreamAdapter.java 489397 2006-12-21 16:28:51Z rwinston $ 41 */ 42 public class CopyStreamAdapter implements CopyStreamListener 43 { 44 private ListenerList internalListeners; 45 46 /** 47 * Creates a new copyStreamAdapter. 48 */ 49 public CopyStreamAdapter() 50 { 51 internalListeners = new ListenerList(); 52 } 53 54 /** 55 * This method is invoked by a CopyStreamEvent source after copying 56 * a block of bytes from a stream. The CopyStreamEvent will contain 57 * the total number of bytes transferred so far and the number of bytes 58 * transferred in the last write. The CopyStreamAdapater will relay 59 * the event to all of its registered listeners, listing itself as the 60 * source of the event. 61 * @param event The CopyStreamEvent fired by the copying of a block of 62 * bytes. 63 */ 64 public void bytesTransferred(CopyStreamEvent event) 65 { 66 bytesTransferred(event.getTotalBytesTransferred(), 67 event.getBytesTransferred(), 68 event.getStreamSize()); 69 } 70 71 /** 72 * This method is not part of the JavaBeans model and is used by the 73 * static methods in the org.apache.commons.io.Util class for efficiency. 74 * It is invoked after a block of bytes to inform the listener of the 75 * transfer. The CopyStreamAdapater will create a CopyStreamEvent 76 * from the arguments and relay the event to all of its registered 77 * listeners, listing itself as the source of the event. 78 * @param totalBytesTransferred The total number of bytes transferred 79 * so far by the copy operation. 80 * @param bytesTransferred The number of bytes copied by the most recent 81 * write. 82 * @param streamSize The number of bytes in the stream being copied. 83 * This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if 84 * the size is unknown. 85 */ 86 public void bytesTransferred(long totalBytesTransferred, 87 int bytesTransferred, long streamSize) 88 { 89 CopyStreamEvent event; 90 91 event = new CopyStreamEvent(this, 92 totalBytesTransferred, 93 bytesTransferred, 94 streamSize); 95 96 for (EventListener listener : internalListeners) 97 { 98 ((CopyStreamListener) (listener)).bytesTransferred(event); 99 } 100 } 101 102 /** 103 * Registers a CopyStreamListener to receive CopyStreamEvents. 104 * Although this method is not declared to be synchronized, it is 105 * implemented in a thread safe manner. 106 * @param listener The CopyStreamlistener to register. 107 */ 108 public void addCopyStreamListener(CopyStreamListener listener) 109 { 110 internalListeners.addListener(listener); 111 } 112 113 /** 114 * Unregisters a CopyStreamListener. Although this method is not 115 * synchronized, it is implemented in a thread safe manner. 116 * @param listener The CopyStreamlistener to unregister. 117 */ 118 public void removeCopyStreamListener(CopyStreamListener listener) 119 { 120 internalListeners.removeListener(listener); 121 } 122 }