/**
* Register a particular listener for a particular message type. More than one listener can be
* registered for each message type.
*
* @param m specify message type and template we're listening for
* @param listener destination for received messages
*/
public void registerListener(Message template, MessageListener listener) {
Integer amType = new Integer(template.amType());
Vector vec = (Vector) templateTbl.get(amType);
if (vec == null) {
vec = new Vector();
}
vec.addElement(new msgTemplate(template, listener));
templateTbl.put(amType, vec);
}
/**
* Stop listening for messages of the given type with the given listener.
*
* @param m specify message type and template we're listening for
* @param listener destination for received messages
*/
public void deregisterListener(Message template, MessageListener listener) {
Integer amType = new Integer(template.amType());
Vector vec = (Vector) templateTbl.get(amType);
if (vec == null) {
throw new IllegalArgumentException(
"No listeners registered for message type "
+ template.getClass().getName()
+ " (AM type "
+ template.amType()
+ ")");
}
msgTemplate mt = new msgTemplate(template, listener);
// Remove all occurrences
while (vec.removeElement(mt)) ;
if (vec.size() == 0) templateTbl.remove(amType);
}
public void packetReceived(byte[] packet) {
// XXX: hack: with the new packetsource format, packet does not
// contain a crc field, so numElements_data() will be wrong. But we
// access the data area via dataSet/dataGet, so we're ok.
// this is where the source comes in to create the correct packet
final TOSMsg msg = messageFactory.createTOSMsg(packet);
if (DEBUG) Dump.dump("Received message", packet);
if (drop_bad_crc && msg.get_crc() != 0x01) {
// Drop message
if (DISPLAY_ERROR_MSGS) Dump.dump("Dropping packet with bad CRC", packet);
return;
}
if (groupId == MoteIF.ANY_GROUP_ID || msg.get_group() == groupId) {
Integer type = new Integer(msg.get_type());
Vector vec = (Vector) templateTbl.get(type);
if (vec == null) {
if (DEBUG)
Dump.dump(
"Received packet with type " + msg.get_type() + ", but no listeners registered",
packet);
return;
}
int length = msg.get_length();
Enumeration en = vec.elements();
while (en.hasMoreElements()) {
msgTemplate temp = (msgTemplate) en.nextElement();
Message received;
// Erk - end up cloning the message multiple times in case
// different templates used for different listeners
try {
received = temp.template.clone(length);
received.dataSet(msg.dataGet(), msg.offset_data(0), 0, length);
} catch (ArrayIndexOutOfBoundsException e) {
/*
* Note: this will not catch messages whose length is
* incorrect, but less than DATA_LENGTH (see AM.h) + 2
*/
error(temp, "invalid length message received (too long)");
continue;
} catch (Exception e) {
error(temp, "couldn't clone message!");
continue;
}
/*
* Messages that are longer than the template might have a
* variable-sized array at their end
*/
if (temp.template.dataGet().length > length) {
error(temp, "invalid length message received (too short)");
continue;
}
temp.listener.messageReceived(msg.get_addr(), received);
}
} else {
if (DISPLAY_ERROR_MSGS) Dump.dump("Dropping packet with bad group ID", packet);
}
}