Java Reference
In-Depth Information
Example 5•9: Server.java (continued)
ThreadGroup threadGroup;
// The threadgroup for all our threads
PrintWriter logStream;
// Where we send our logging output to
/**
* This is the Server() constructor. It must be passed a stream
* to send log output to (may be null), and the limit on the number of
* concurrent connections.
**/
public Server(OutputStream logStream, int maxConnections) {
setLogStream(logStream);
log("Starting server");
threadGroup = new ThreadGroup(Server.class.getName());
this.maxConnections = maxConnections;
services = new HashMap();
connections = new HashSet(maxConnections);
}
/**
* A public method to set the current logging stream. Pass null
* to turn logging off
**/
public synchronized void setLogStream(OutputStream out) {
if (out != null) logStream = new PrintWriter(out);
else logStream = null;
}
/** Write the specified string to the log */
protected synchronized void log(String s) {
if (logStream != null) {
logStream.println("[" + new Date() + "] " + s);
logStream.flush();
}
}
/** Write the specified object to the log */
protected void log(Object o) { log(o.toString()); }
/**
* This method makes the server start providing a new service.
* It runs the specified Service object on the specified port.
**/
public synchronized void addService(Service service, int port)
throws IOException
{
Integer key = new Integer(port); // the hashtable key
// Check whether a service is already on that port
if (services.get(key) != null)
throw new IllegalArgumentException("Port " + port +
" already in use.");
// Create a Listener object to listen for connections on the port
Listener listener = new Listener(threadGroup, port, service);
// Store it in the hashtable
services.put(key, listener);
// Log it
log("Starting service " + service.getClass().getName() +
" on port " + port);
// Start the listener running.
listener.start();
}
