* track handshake status of connection. */
public List<ByteBuffer> respond(List<ByteBuffer> buffers,
Transceiver connection) throws IOException {
Decoder in = DecoderFactory.get().binaryDecoder(
new ByteBufferInputStream(buffers), null);
ByteBufferOutputStream bbo = new ByteBufferOutputStream();
BinaryEncoder out = EncoderFactory.get().binaryEncoder(bbo, null);
Exception error = null;
RPCContext context = new RPCContext();
List<ByteBuffer> payload = null;
List<ByteBuffer> handshake = null;
boolean wasConnected = connection != null && connection.isConnected();
try {
Protocol remote = handshake(in, out, connection);
out.flush();
if (remote == null) // handshake failed
return bbo.getBufferList();
handshake = bbo.getBufferList();
// read request using remote protocol specification
context.setRequestCallMeta(META_READER.read(null, in));
String messageName = in.readString(null).toString();
Message rm = remote.getMessages().get(messageName);
if (rm == null)
throw new AvroRuntimeException("No such remote message: "+messageName);
Message m = getLocal().getMessages().get(messageName);
if (m == null)
throw new AvroRuntimeException("No message named "+messageName
+" in "+getLocal());
Object request = readRequest(rm.getRequest(), m.getRequest(), in);
context.setMessage(rm);
for (RPCPlugin plugin : rpcMetaPlugins) {
plugin.serverReceiveRequest(context);
}
// create response using local protocol specification
if ((m.isOneWay() != rm.isOneWay()) && wasConnected)
throw new AvroRuntimeException("Not both one-way: "+messageName);
Object response = null;
try {
REMOTE.set(remote);
response = respond(m, request);
context.setResponse(response);
} catch (Exception e) {
error = e;
context.setError(error);
LOG.warn("user error", e);
} finally {
REMOTE.set(null);
}
if (m.isOneWay() && wasConnected) // no response data
return null;
out.writeBoolean(error != null);
if (error == null)
writeResponse(m.getResponse(), response, out);
else
try {
writeError(m.getErrors(), error, out);
} catch (UnresolvedUnionException e) { // unexpected error
throw error;
}
} catch (Exception e) { // system error
LOG.warn("system error", e);
context.setError(e);
bbo = new ByteBufferOutputStream();
out = EncoderFactory.get().binaryEncoder(bbo, null);
out.writeBoolean(true);
writeError(Protocol.SYSTEM_ERRORS, new Utf8(e.toString()), out);
if (null == handshake) {
handshake = new ByteBufferOutputStream().getBufferList();
}
}
out.flush();
payload = bbo.getBufferList();
// Grab meta-data from plugins
context.setResponsePayload(payload);
for (RPCPlugin plugin : rpcMetaPlugins) {
plugin.serverSendResponse(context);
}
META_WRITER.write(context.responseCallMeta(), out);
out.flush();
// Prepend handshake and append payload
bbo.prepend(handshake);
bbo.append(payload);
return bbo.getBufferList();
}