/**
* Creates a new entry if not yet present. Adds the fragment. If all fragements for a given
* message have been received, an entire message is reassembled and returned. Otherwise null is
* returned.
*
* @param id - the message ID, unique for a sender
* @param frag_id the index of this fragmentation (0..tot_frags-1)
* @param tot_frags the total number of fragmentations expected
* @param fragment - the byte buffer for this fragment
*/
public synchronized byte[] add(long id, int frag_id, int tot_frags, byte[] fragment) {
byte[] retval = null; // initialize the return value to default not complete
FragEntry e = table.get(id);
if (e == null) { // Create new entry if not yet present
e = new FragEntry(id, tot_frags);
table.put(id, e);
}
e.set(frag_id, fragment);
if (e.isComplete()) {
retval = e.assembleBuffer();
table.remove(id);
}
return retval;
}
/**
* 1. Get all the fragment buffers 2. When all are received -> Assemble them into one big buffer
* 3. Read headers and byte buffer from big buffer 4. Set headers and buffer in msg 5. Pass msg up
* the stack
*/
private void unfragment(Message msg, FragHeader hdr) {
Address sender = msg.getSrc();
Message assembled_msg = null;
ConcurrentMap<Long, FragEntry> frag_table = fragment_list.get(sender);
if (frag_table == null) {
frag_table = Util.createConcurrentMap(16, .075f, 16);
ConcurrentMap<Long, FragEntry> tmp = fragment_list.putIfAbsent(sender, frag_table);
if (tmp != null) // value was already present
frag_table = tmp;
}
num_received_frags.incrementAndGet();
FragEntry entry = frag_table.get(hdr.id);
if (entry == null) {
entry = new FragEntry(hdr.num_frags);
FragEntry tmp = frag_table.putIfAbsent(hdr.id, entry);
if (tmp != null) entry = tmp;
}
entry.lock();
try {
entry.set(hdr.frag_id, msg);
if (entry.isComplete()) {
assembled_msg = entry.assembleMessage();
frag_table.remove(hdr.id);
}
} finally {
entry.unlock();
}
// assembled_msg=frag_table.add(hdr.id, hdr.frag_id, hdr.num_frags, msg);
if (assembled_msg != null) {
try {
if (log.isTraceEnabled()) log.trace("assembled_msg is " + assembled_msg);
assembled_msg.setSrc(sender); // needed ? YES, because fragments have a null src !!
num_received_msgs.incrementAndGet();
up_prot.up(new Event(Event.MSG, assembled_msg));
} catch (Exception e) {
if (log.isErrorEnabled()) log.error("unfragmentation failed", e);
}
}
}
