/**
* Sends an RPC request to the given {@link InetSocketAddress}.
*
* @param remoteSocketAddress the remote address to send the request to
* @param request the RPC request to send
* @return the return value of the RPC call, possibly <code>null</code>
* @throws Throwable any exception that is thrown by the remote receiver of the RPC call
*/
Object sendRPCRequest(final InetSocketAddress remoteSocketAddress, final RPCRequest request)
throws Throwable {
if (this.shutdownRequested.get())
throw new IOException("Shutdown of RPC service has already been requested");
final long start = System.currentTimeMillis();
final DatagramPacket[] packets = this.messageToPackets(remoteSocketAddress, request);
final Integer messageID = Integer.valueOf(request.getMessageID());
final RPCRequestMonitor requestMonitor = new RPCRequestMonitor();
this.pendingRequests.put(messageID, requestMonitor);
RPCResponse rpcResponse = null;
int numberOfRetries;
try {
numberOfRetries = this.networkThread.send(packets);
// Wait for the response
synchronized (requestMonitor) {
while (true) {
if (requestMonitor.rpcResponse != null) {
rpcResponse = requestMonitor.rpcResponse;
break;
}
final long sleepTime = RPC_TIMEOUT - (System.currentTimeMillis() - start);
if (sleepTime > 0L) requestMonitor.wait(sleepTime);
else break;
}
}
} finally {
// Request is no longer pending
this.pendingRequests.remove(messageID);
}
if (rpcResponse == null)
throw new IOException(
"Unable to complete RPC of method "
+ request.getMethodName()
+ " on "
+ remoteSocketAddress);
// Report the successful call to the statistics module
final String methodName = request.getMethodName();
this.statistics.reportSuccessfulTransmission(methodName, packets.length, numberOfRetries);
this.statistics.reportRTT(methodName, (int) (System.currentTimeMillis() - start));
// TODO: Send clean up message
if (rpcResponse instanceof RPCReturnValue) return ((RPCReturnValue) rpcResponse).getRetVal();
throw ((RPCThrowable) rpcResponse).getThrowable();
}
private void processIncomingRPCRequest(
final InetSocketAddress remoteSocketAddress, final RPCRequest rpcRequest) {
final Integer messageID = Integer.valueOf(rpcRequest.getMessageID());
if (this.requestsBeingProcessed.putIfAbsent(messageID, rpcRequest) != null) {
Log.debug(
"Request " + rpcRequest.getMessageID() + " is already being processed at the moment");
return;
}
final CachedResponse cachedResponse = this.cachedResponses.get(messageID);
if (cachedResponse != null) {
try {
final int numberOfRetries = this.networkThread.send(cachedResponse.packets);
this.statistics.reportSuccessfulTransmission(
rpcRequest.getMethodName() + " (Response)",
cachedResponse.packets.length,
numberOfRetries);
} catch (final Exception e) {
Log.error("Caught exception while trying to send RPC response: ", e);
} finally {
this.requestsBeingProcessed.remove(messageID);
}
return;
}
final RPCProtocol callbackHandler = this.callbackHandlers.get(rpcRequest.getInterfaceName());
if (callbackHandler == null) {
Log.error("Cannot find callback handler for protocol " + rpcRequest.getInterfaceName());
this.requestsBeingProcessed.remove(messageID);
return;
}
try {
final Method method =
callbackHandler
.getClass()
.getMethod(rpcRequest.getMethodName(), rpcRequest.getParameterTypes());
RPCResponse rpcResponse = null;
try {
final Object retVal = method.invoke(callbackHandler, rpcRequest.getArgs());
rpcResponse = new RPCReturnValue(rpcRequest.getMessageID(), retVal);
} catch (final InvocationTargetException ite) {
Throwable targetException = ite.getTargetException();
// Make sure the stack trace is correctly filled
targetException.getStackTrace();
if (!this.isThrowableRegistered(targetException.getClass()))
targetException = wrapInIOException(rpcRequest, targetException);
rpcResponse = new RPCThrowable(rpcRequest.getMessageID(), targetException);
}
final DatagramPacket[] packets = this.messageToPackets(remoteSocketAddress, rpcResponse);
this.cachedResponses.put(messageID, new CachedResponse(System.currentTimeMillis(), packets));
final int numberOfRetries = this.networkThread.send(packets);
this.statistics.reportSuccessfulTransmission(
rpcRequest.getMethodName() + " (Response)", packets.length, numberOfRetries);
} catch (final Exception e) {
Log.error("Caught processing RPC request: ", e);
} finally {
this.requestsBeingProcessed.remove(messageID);
}
}
