public int enqueue(int messageNo, IMessage message, MessageFuture future) throws IOException {
QueueEntry qe = new QueueEntry();
qe.messageNo = messageNo;
qe.score = computeMessageScore(messageNo, message);
qe.messageClass = message.getClass();
qe.messageStream = messenger.serializeMessage(message);
qe.future = future;
if (LogUtil.isLogAvailable()) {
// precompute the expected queue size...this is because the writer thread may quickly pick
// up the queue item which, while swell, means the debug output may be confusing
int newExpectedQueueSize = queue.size() + 1;
Log.i(
TAG,
"Message "
+ qe.messageNo
+ " enqueued, it's a "
+ qe.messageClass.getSimpleName()
+ ", "
+ qe.messageStream.available()
+ " bytes in length, "
+ newExpectedQueueSize
+ " entries in the queue");
}
queue.add(qe);
return qe.messageNo;
}
/**
* Write one message (or part of a message) to the connected output stream.
*
* <p>This may write a partial message, if the message is bigger than our output buffer. If this
* is the case, the queue entry is readded to the priority queue and given another chance to write
* more data. This is repeated until the message is completely sent. Note that this means other,
* higher priority messages may jump the line while this message is in the middle of sending its
* data. This is ok, and how we allow the system to send command messages when long transfer
* messages are in progress.
*
* @throws IOException
*/
public void writeOne() throws IOException {
// process canceled entires first
processCanceled();
// then process the next entry to be sent
QueueEntry qe = nextQueueEntry();
if (qe != null) {
int read = qe.messageStream.read(outBytes);
if (LogUtil.isLogAvailable()) {
Log.d(
TAG,
"Message "
+ qe.messageNo
+ " written, it's a "
+ qe.messageClass.getSimpleName()
+ ", "
+ read
+ " bytes in length");
}
outStream.write(outBytes, 0, read);
int left = qe.messageStream.available();
// if there are bytes left to write, add this message back into the queue
// to write at the next opportunity
if (left > 0) {
if (LogUtil.isLogAvailable()) {
Log.d(TAG, "Message " + qe.messageNo + ", " + left + " bytes left to write");
}
queue.add(qe);
} else {
qe.future.setFinished(true);
// otherwise, we're done
if (LogUtil.isLogAvailable()) {
Log.i(TAG, "Message " + qe.messageNo + " finished writing");
}
}
}
}
private void processCanceled() throws IOException {
Set<Integer> canceled = new HashSet<Integer>();
synchronized (queueLock) {
canceled.addAll(this.canceled);
this.canceled.clear();
}
for (int messageNo : canceled) {
QueueEntry found = removeQueueEntry(messageNo);
if (found != null) {
if (LogUtil.isLogAvailable()) {
Log.d(TAG, "Message " + messageNo + " canceled");
}
PacketFormat cancelPacket = new PacketFormat(messageNo, new byte[0]);
cancelPacket.addControlCode(ControlCode.Cancelled);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
cancelPacket.serialize(baos);
found.messageStream = new ByteArrayInputStream(baos.toByteArray());
found.score = messageNo * CANCEL_TRANSFER_SCORE_MULTIPLIER;
queue.add(found);
}
}
}