/**
* Return a control message per an encoded status code
*
* @param encoded
* @return
*/
static ControlMessage mkMessage(short encoded) {
for (ControlMessage cm : ControlMessage.values()) {
if (encoded == cm.code) return cm;
}
return null;
}
/*
* Each ControlMessage is encoded as: code (<0) ... short(2) Each
* TaskMessage is encoded as: task (>=0) ... short(2) len ... int(4) payload
* ... byte[] *
*/
protected Object decode(ChannelHandlerContext ctx, Channel channel, ChannelBuffer buf)
throws Exception {
// Make sure that we have received at least a short
long available = buf.readableBytes();
// Length of control message is 10.
// Minimum length of a task message is 6(short taskId, int length).
if (available < 10) {
// need more data
return null;
}
Long startTime = null;
if (isServer) {
startTime = System.nanoTime();
}
try {
// Mark the current buffer position before reading task/len field
// because the whole frame might not be in the buffer yet.
// We will reset the buffer position to the marked position if
// there's not enough bytes in the buffer.
buf.markReaderIndex();
// read the short field
short code = buf.readShort();
available -= 2;
// case 1: Control message
ControlMessage ctrl_msg = ControlMessage.mkMessage(code);
if (ctrl_msg != null) {
if (available < 12) {
// The time stamp bytes were not received yet - return null.
buf.resetReaderIndex();
return null;
}
long timeStamp = buf.readLong();
int clientPort = buf.readInt();
available -= 12;
if (ctrl_msg == ControlMessage.EOB_MESSAGE) {
long interval = System.currentTimeMillis() - timeStamp;
if (interval > 0) {
Histogram netTransTime = getTransmitHistogram(channel, clientPort);
if (netTransTime != null) {
netTransTime.update(interval);
}
}
recvSpeed.update(Double.valueOf(ControlMessage.encodeLength()));
}
return ctrl_msg;
}
// case 2: task Message
short task = code;
// Make sure that we have received at least an integer (length)
if (available < 8) {
// need more data
buf.resetReaderIndex();
return null;
}
// Read the length field.
int length = buf.readInt();
if (length <= 0) {
LOG.info("Receive one message whose TaskMessage's message length is {}", length);
return new TaskMessage(task, null);
}
int headerLength = buf.readInt();
if (headerLength <= 0) {
LOG.info("Receive one message whose TaskMessage's message header length is {}", length);
}
// Make sure if there's enough bytes in the buffer.
available -= 8;
if (available < length + headerLength) {
// The whole bytes were not received yet - return null.
buf.resetReaderIndex();
return null;
}
String component = null;
String stream = null;
if (headerLength > 0) {
ChannelBuffer header = buf.readBytes(headerLength);
String headerValue = new String(header.array());
String splits[] = headerValue.split(" ");
stream = splits[0];
component = splits[1];
}
// There's enough bytes in the buffer. Read it.
ChannelBuffer payload = buf.readBytes(length);
// Successfully decoded a frame.
// Return a TaskMessage object
byte[] rawBytes = payload.array();
// @@@ TESTING CODE
// LOG.info("Receive task:{}, length: {}, data:{}",
// task, length, JStormUtils.toPrintableString(rawBytes));
TaskMessage ret = new TaskMessage(task, rawBytes, component, stream);
recvSpeed.update(Double.valueOf(rawBytes.length + 6));
return ret;
} finally {
if (isServer) {
Long endTime = System.nanoTime();
timer.update((endTime - startTime) / 1000000.0d);
}
}
}