tuwien.auto.calimero.internal.UdpSocketLooper Maven / Gradle / Ivy
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/*
Calimero 2 - A library for KNX network access
Copyright (c) 2010, 2011 B. Malinowsky
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
Linking this library statically or dynamically with other modules is
making a combined work based on this library. Thus, the terms and
conditions of the GNU General Public License cover the whole
combination.
As a special exception, the copyright holders of this library give you
permission to link this library with independent modules to produce an
executable, regardless of the license terms of these independent
modules, and to copy and distribute the resulting executable under terms
of your choice, provided that you also meet, for each linked independent
module, the terms and conditions of the license of that module. An
independent module is a module which is not derived from or based on
this library. If you modify this library, you may extend this exception
to your version of the library, but you are not obligated to do so. If
you do not wish to do so, delete this exception statement from your
version.
*/
package tuwien.auto.calimero.internal;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.net.DatagramPacket;
import java.net.DatagramSocket;
import java.net.InetSocketAddress;
import java.net.SocketTimeoutException;
/**
* @author B. Malinowsky
*/
public abstract class UdpSocketLooper
{
/**
* The socket on which to loop. It must be initialized during construction, either by
* supplying an already initialized socket using a constructor of this class, or
* directly assigning it in a constructor of a derived class
*/
protected DatagramSocket s;
/**
* The socket timeout, set 0 for no timeout.
*/
private final int timeout;
private final int maxRcvBuf;
private final int total;
private final boolean closeSocket;
private volatile boolean quit;
/**
* Creates a socket looper for the supplied UDP socket.
*
*
* @param socket the UDP socket to loop on
* @param closeSocket true to close the socket on {@link #quit()},
* false otherwise
*/
public UdpSocketLooper(final DatagramSocket socket, final boolean closeSocket)
{
this(socket, closeSocket, 512, 0, 0);
}
/**
* Creates a socket looper for the supplied UDP socket and timeout parameters.
*
*
* @param socket the UDP socket to loop on
* @param closeSocket true to close the socket on {@link #quit()},
* false otherwise
* @param receiveBufferSize sets the maximum size of the socket receive buffer
* @param socketTimeout the socket's receive method shall time out after a maximum of
* socketTimeout milliseconds
* @param loopTimeout this looper shall quit after loopTimeout milliseconds
*/
public UdpSocketLooper(final DatagramSocket socket, final boolean closeSocket,
final int receiveBufferSize, final int socketTimeout, final int loopTimeout)
{
s = socket;
maxRcvBuf = receiveBufferSize;
timeout = socketTimeout;
total = loopTimeout;
this.closeSocket = closeSocket;
}
/**
* Runs the looper.
*
*
* @throws IOException
*/
public void loop() throws IOException
{
final long start = System.currentTimeMillis();
final byte[] buf = new byte[maxRcvBuf];
try {
if (timeout > 0)
s.setSoTimeout(timeout);
while (!quit) {
if (total > 0) {
final long now = System.currentTimeMillis();
int to = (int) (start + total - now);
if (to <= 0)
break;
// query socket timeout directly from socket since subtypes might
// have modified the timeout during looping
final int sto = s.getSoTimeout();
if (sto > 0)
to = Math.min(to, sto);
s.setSoTimeout(to);
}
try {
final DatagramPacket p = new DatagramPacket(buf, buf.length);
s.receive(p);
final byte[] data = p.getData();
onReceive((InetSocketAddress) p.getSocketAddress(), data, p.getOffset(),
p.getLength());
}
catch (final SocketTimeoutException e) {
if (total == 0 || start + total > System.currentTimeMillis())
onTimeout();
}
}
}
catch (final InterruptedIOException e) {
Thread.currentThread().interrupt();
}
catch (final IOException e) {
if (!quit)
throw e;
}
finally {
quit();
}
}
/**
* Invoked on socket timeout.
*
*/
protected void onTimeout()
{}
/**
* Invoked on receiving a datagram over the socket.
*
*
* @param source the sender's address, where the data is coming from
* @param data the received data
* @param offset offset of the data (see {@link DatagramPacket#getOffset()})
* @param length length of the data (see {@link DatagramPacket#getLength()})
* @throws IOException on communication errors while processing the received data
*/
protected abstract void onReceive(InetSocketAddress source, byte[] data, int offset, int length)
throws IOException;
/**
* Quits the looper.
*
* If closing the socket was requested during construction of this looper, the socket
* is closed.
*/
public void quit()
{
// On platforms with non-interruptible network sockets, the receiver
// might not handle the interrupt flag for a longer period of time.
// That's why the closeSocket option can be set during construction.
quit = true;
if (closeSocket)
s.close();
}
}