For my project, I am using the UDP library to communicate with 3 Arduinos via Wifly modules. Everything is working fine, except receive listener seems to be blocked after a couple of minutes. If a udp message is not sent to an arduino after a while, processing will stop receiving messages from the address.  I've been using Wireshark to view the network activity and there haven't been any dropped packets.

Anyone else have the same issue? Below is how I have setup the udp communication. I could just send a random message if nothing has been sent for a certain amount of time, but I was wondering if there was an easy way to turn off the blocking.

1. //works with udp  test for send/receive, 2 way comm.
2. // import UDP library
3. import hypermedia.net.*;
4. 
   
5. UDP udp;  // define the UDP object
6. boolean sendMsg = false;
7. boolean send = false;
8. int currentTime = 0;
9. int prevTime = 0;
10. int interval = 2000; //no buffer overrun on arduino
11. 
    
12. /**
13.  * init
14.  */
15. void setup() {
16. 
    
17.   // create a new datagram connection on port 4001
18.   // and wait for incoming message
19.   udp = new UDP( this, 4001 );
20.   //udp.log( true ); // <-- printout the connection activity
21.   udp.listen( true );
22. }
23. 
    
24. //process events
25. void draw() {
26. 
    
27.   currentTime = millis();
28.   if((currentTime - prevTime) > interval)
29.   {
30.     prevTime = currentTime;
31.     if(sendMsg == true)
32.     {
33.       if(send == true)
34.       {
35.         String ip = "172.16.2.4";  // the remote IP address
36.         int port = 4000;    // the destination port
37.         String message = "225;255;255;h;@";
38.         udp.send( message, ip, port );
39.                 
40.         println( "send: \""+message+"\" to "+ip+" on port "+port );
41.         
42.         String ip2 = "172.16.2.3";  // the remote IP address
43.         udp.send( message, ip2, port );
44.                 
45.         println( "send: \""+message+"\" to "+ip2+" on port "+port );
46.         
47.         send = false;
48.       }
49.       else
50.       {
51.         String ip = "172.16.2.4";  // the remote IP address
52.         int port = 4000;    // the destination port
53.         String message = "0;0;0;l;@";
54.         udp.send( message, ip, port );
55. 
    
56.         println( "send: \""+message+"\" to "+ip+" on port "+port );
57.          
58.         String ip2 = "172.16.2.3";  // the remote IP address
59.         udp.send( message, ip2, port );
60.         
61.         println( "send: \""+message+"\" to "+ip2+" on port "+port );
62.          
63.         send = true;
64.       }
65.     }
66.   }
67. 
    
68. }
69. 
    
70. /** 
71.  * on key pressed event:
72.  * send the current key value over the network
73.  */
74. void keyPressed() {
75.     
76.     String message  = str( key ); // the message to send
77.     String ip       = "172.16.2.4"; // the remote IP address
78.     int port        = 4000; // the destination port
79.     
80.     println( "send: \""+message+"\" to "+ip+" on port "+port );
81.     
82.     // formats the message for Pd
83.     message = "225;255;255;" + message + ";@";
84.     //message = "hello";
85.     // send the message
86.     udp.send( message, ip, port );
87.   
88. }
89. 
    
90. /**
91.  * To perform any action on datagram reception, you need to implement this 
92.  * handler in your code. This method will be automatically called by the UDP 
93.  * object each time he receive a nonnull message.
94.  * By default, this method have just one argument (the received message as 
95.  * byte[] array), but in addition, two arguments (representing in order the 
96.  * sender IP address and his port) can be set like below.
97.  */
98. // void receive( byte[] data ) { // <-- default handler
99. void receive( byte[] data, String ip, int port ) { // <-- extended handler
100.   
101.   
102.   // get the "real" message =
103.   // forget the ";\n" at the end <-- !!! only for a communication with Pd !!!
104.   data = subset(data, 0, data.length-2);
105.   String message = new String( data );
106.   
107.   // print the result
108.   println( "receive: \""+message+"\" from "+ip+" on port "+port );
109. }