/*
* Copyright 2001-2004 The Apache Software Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.commons.net.io;
import java.util.Enumeration;
import org.apache.commons.net.util.ListenerList;
/**
* The CopyStreamAdapter will relay CopyStreamEvents to a list of listeners
* when either of its bytesTransferred() methods are called. Its purpose
* is to facilitate the notification of the progress of a copy operation
* performed by one of the static copyStream() methods in
* org.apache.commons.io.Util to multiple listeners. The static
* copyStream() methods invoke the
* bytesTransfered(long, int) of a CopyStreamListener for performance
* reasons and also because multiple listeners cannot be registered given
* that the methods are static.
* <p>
* <p>
* @see CopyStreamEvent
* @see CopyStreamListener
* @see Util
* @author <a href="mailto:savarese@apache.org">Daniel F. Savarese</a>
* @version $Id: CopyStreamAdapter.java,v 1.9 2004/02/29 10:26:55 scolebourne Exp $
*/
public class CopyStreamAdapter implements CopyStreamListener
{
private ListenerList internalListeners;
/**
* Creates a new copyStreamAdapter.
*/
public CopyStreamAdapter()
{
internalListeners = new ListenerList();
}
/**
* 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 bytes transferred so far and the number of bytes
* transferred in the last write. The CopyStreamAdapater will relay
* the event to all of its registered listeners, listing itself as the
* source of the event.
* @param event The CopyStreamEvent fired by the copying of a block of
* bytes.
*/
public void bytesTransferred(CopyStreamEvent event)
{
bytesTransferred(event.getTotalBytesTransferred(),
event.getBytesTransferred(),
event.getStreamSize());
}
/**
* 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 after a block of bytes to inform the listener of the
* transfer. The CopyStreamAdapater will create a CopyStreamEvent
* from the arguments and relay the event to all of its registered
* listeners, listing itself as the source of the event.
* @param totalBytesTransferred The total number of bytes transferred
* so far by the copy operation.
* @param bytesTransferred The number of bytes copied by the most recent
* write.
* @param streamSize The number of bytes in the stream being copied.
* This may be equal to CopyStreamEvent.UNKNOWN_STREAM_SIZE if
* the size is unknown.
*/
public void bytesTransferred(long totalBytesTransferred,
int bytesTransferred, long streamSize)
{
Enumeration listeners;
CopyStreamEvent event;
listeners = internalListeners.getListeners();
event = new CopyStreamEvent(this,
totalBytesTransferred,
bytesTransferred,
streamSize);
while (listeners.hasMoreElements())
{
((CopyStreamListener) (listeners.nextElement())).
bytesTransferred(event);
}
}
/**
* Registers a CopyStreamListener to receive CopyStreamEvents.
* Although this method is not declared to be synchronized, it is
* implemented in a thread safe manner.
* @param listener The CopyStreamlistener to register.
*/
public void addCopyStreamListener(CopyStreamListener listener)
{
internalListeners.addListener(listener);
}
/**
* Unregisters a CopyStreamListener. Although this method is not
* synchronized, it is implemented in a thread safe manner.
* @param listener The CopyStreamlistener to unregister.
*/
public void removeCopyStreamListener(CopyStreamListener listener)
{
internalListeners.removeListener(listener);
}
}