/*
* This file is part of muCommander, http://www.mucommander.com
* Copyright (C) 2002-2016 Maxence Bernard
*
* muCommander is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* muCommander is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
package com.mucommander.commons.io;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Enumeration;
import java.util.Vector;
/**
* <code>MultiOutputStream</code> 'multiplies' a stream by forwarding the data that is written to it to several
* registered output streams. Similarly, {@link #flush()} and {@link #close()} call the same method on all registered
* output streams.
* Until one or more OutputStream is registered, this stream acts as a sink: all OutputStream operations are no-ops.
*
* @author Maxence Bernard
*/
public class MultiOutputStream extends OutputStream {
/** Registered OutputStreams */
protected Vector<OutputStream> streams = new Vector<OutputStream>();
/**
* Creates a new MultiOutputStream that initially contains no OutputStream. * Until one or more OutputStream is
* registered, this stream acts as a sink: all OutputStream operations are no-ops.
*/
public MultiOutputStream() {
}
/**
* Adds an <code>OutputStream</code> to the list of destination output streams. This method doesn't check whether
* the specified stream already exists in the list, so the same output stream may be added several times.
*
* @param out the OutputStream to add
*/
public synchronized void addOutputStream(OutputStream out) {
streams.add(out);
}
/**
* Removes the first occurrence of the given <code>OutputStream</code> from the list of destination output streams.
* If the same stream was added several times, this method has to be called that many times to remove it entirely.
*
* @param out the OutputStream to add
*/
public synchronized void removeOutputStream(OutputStream out) {
streams.remove(out);
}
/**
* Returns <code>true</code> if the specified stream is present in the list of destination output streams.
*
* @param out the OutputStream to look for
* @return <code>true</code> if the specified stream is present in the list of destination output streams
*/
public synchronized boolean containsOutputStream(OutputStream out) {
return streams.contains(out);
}
/**
* Returns an {@link java.util.Enumeration} of the destination output streams. This instance should be synchronized
* externally to ensure that the list of streams is not modified while it is being enumerated.
*
* @return an {@link java.util.Enumeration} of the destination output streams
*/
public synchronized Enumeration<OutputStream> enumOutputStream() {
return streams.elements();
}
/////////////////////////////////
// OutputStream implementation //
/////////////////////////////////
/**
* Calls <code>write(b)</code> with the specified byte on each of the destination output streams.
* <p>
* Any IOException thrown by any of the destination output stream is immediately re-thrown, aborting the write
* as a whole.
* </p>
*/
@Override
public synchronized void write(int b) throws IOException {
Enumeration<OutputStream> elements = streams.elements();
while(elements.hasMoreElements())
elements.nextElement().write(b);
}
/**
* Calls <code>write(b,off,len)</code> with the specified parameters on each of the destination output streams.
* <p>
* Any IOException thrown by any of the destination output stream is immediately re-thrown, aborting the operation
* as a whole.
* </p>
*/
@Override
public synchronized void write(byte b[], int off, int len) throws IOException {
Enumeration<OutputStream> elements = streams.elements();
while(elements.hasMoreElements())
elements.nextElement().write(b, off, len);
}
/**
* Calls <code>write(b)</code> with the specified parameter on each of the destination output streams.
* <p>
* Any IOException thrown by any of the destination output stream is immediately re-thrown, aborting the operation
* as a whole.
* </p>
*/
@Override
public synchronized void write(byte b[]) throws IOException {
Enumeration<OutputStream> elements = streams.elements();
while(elements.hasMoreElements())
elements.nextElement().write(b);
}
/**
* Calls <code>flush</code> on each of the destination output streams.
* <p>
* Any IOException thrown by any of the destination output stream is immediately re-thrown, aborting the operation
* as a whole.
* </p>
*/
@Override
public synchronized void flush() throws IOException {
Enumeration<OutputStream> elements = streams.elements();
while(elements.hasMoreElements())
elements.nextElement().flush();
}
/**
* Calls <code>close</code> on each of the destination output streams.
* <p>
* Any IOException thrown by any of the destination output stream is immediately re-thrown, aborting the operation
* as a whole.
* </p>
*/
@Override
public void close() throws IOException {
Enumeration<OutputStream> elements = streams.elements();
while(elements.hasMoreElements())
elements.nextElement().close();
}
}