/**
* Examines the channel buffer and attempts to match the protocol of the request and invoke the
* matching {@link ProtocolInitiator}.
*
* @param ctx The channel handler context
* @param channel The channel
* @param bufferx The message buffer
* @param e The channel event
* @return The channel buffer to send upstream, or null if we need more bytes
*/
protected ChannelBuffer protocolSwitch(
ChannelHandlerContext ctx, Channel channel, ChannelBuffer bufferx, ChannelEvent e) {
ChannelBuffer cb = preSwitchedBuffer.get(channel);
if (cb != null) {
cb.writeBytes(bufferx);
cb.resetReaderIndex();
} else {
cb = bufferx;
}
// this guy will be set with a matching initiator
ProtocolInitiator selectedInitiator = null;
// this guy will be set to false if at least 1 initiator had insufficient bytes to match
boolean sufficientBytes = true;
// ths guy has the total bytes available in the buffer
final int bytesAvailable = cb.readableBytes();
for (ProtocolInitiator pi : initiators.values()) {
if (pi.requiredBytes() > bytesAvailable) {
sufficientBytes = false;
} else {
if (pi.match(cb)) {
selectedInitiator = pi;
break;
}
}
}
if (selectedInitiator == null) {
// we did not get a match
if (!sufficientBytes) {
// ok, we did not have enough bytes
DynamicChannelBuffer dcb = preSwitchedBuffer.get(channel);
if (dcb == null) {
dcb = new DynamicChannelBuffer(cb.order(), 1024, chanelBufferFactory);
preSwitchedBuffer.set(channel, dcb);
}
dcb.writeBytes(cb);
dcb.resetReaderIndex();
return null;
}
// darn, we have enough bytes for any of the inits,
// but none matched
throw new RuntimeException("Failed to match any protocol initiator");
}
preSwitchedBuffer.remove(channel);
// we matched on an initiator, so have it modify the pipeline
selectedInitiator.modifyPipeline(ctx, channel, cb);
return cb;
// if we get here, it means we did not find a protocol match
// so pass to the default protocol initiator.
}
@Override
protected Object encode(ChannelHandlerContext ctx, Channel channel, Object msg) throws Exception {
if (!(msg instanceof ChannelBuffer)) {
return msg;
}
ChannelBuffer body = (ChannelBuffer) msg;
ChannelBuffer header =
channel.getConfig().getBufferFactory().getBuffer(body.order(), lengthFieldLength);
int length =
lengthIncludesLengthFieldLength
? body.readableBytes() + lengthFieldLength
: body.readableBytes();
switch (lengthFieldLength) {
case 1:
if (length >= 256) {
throw new IllegalArgumentException("length does not fit into a byte: " + length);
}
header.writeByte((byte) length);
break;
case 2:
if (length >= 65536) {
throw new IllegalArgumentException("length does not fit into a short integer: " + length);
}
header.writeShort((short) length);
break;
case 3:
if (length >= 16777216) {
throw new IllegalArgumentException(
"length does not fit into a medium integer: " + length);
}
header.writeMedium(length);
break;
case 4:
header.writeInt(length);
break;
case 8:
header.writeLong(length);
break;
default:
throw new Error("should not reach here");
}
return wrappedBuffer(header, body);
}