/*
* Copyright 2012-2015, the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.flipkart.phantom.thrift.impl;
import org.apache.thrift.TApplicationException;
import org.apache.thrift.TBase;
import org.apache.thrift.TException;
import org.apache.thrift.TServiceClient;
import org.apache.thrift.protocol.TMessage;
import org.apache.thrift.protocol.TMessageType;
import org.apache.thrift.protocol.TProtocol;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
/**
* <code>ProxyServiceClient</code> is a sub-type of the Thrift {@link org.apache.thrift.TServiceClient} that retains the sequence ID of the calling message when
* invoking the target thrift service. It additionally writes the TBase result from a call invocation into the invoking client's {@link org.apache.thrift.protocol.TProtocol} instance
* i.e. relays the service response to the client as is in the Thrift protocol format.
*
* @author devashishshankar
* @author Regunath B
* @version 1.0, 28 Mar 2013
*/
@SuppressWarnings("rawtypes")
public class ProxyServiceClient extends TServiceClient {
/** Logger for this class*/
private static final Logger LOGGER = LoggerFactory.getLogger(ProxyServiceClient.class);
/** The client's TProtocol instance to relay the response to*/
private TProtocol clientProtocol;
/**
* Constructor for this class
* @param clientProtocol the client's TProtocol instance to relay the service response to
* @param iprot the incoming TProtocol from the service
* @param oprot the outgoing TProtocol to the service
*/
public ProxyServiceClient(TProtocol clientProtocol, TProtocol iprot, TProtocol oprot) {
super(iprot, oprot);
this.clientProtocol = clientProtocol;
}
/**
* Overriden super class method. Simply delegates the call to super type implementation
* @see org.apache.thrift.TServiceClient#sendBase(String, org.apache.thrift.TBase)
*/
public void sendBase(String methodName, TBase args, int sequenceId) throws TException {
this.seqid_ = sequenceId;
oprot_.writeMessageBegin(new TMessage(methodName, TMessageType.CALL, this.seqid_));
args.write(oprot_);
oprot_.writeMessageEnd();
oprot_.getTransport().flush();
}
/**
* Overriden super class method. Receives the service response and relays it back to the client
* @see org.apache.thrift.TServiceClient#receiveBase(org.apache.thrift.TBase, String)
*/
public void receiveBase(TBase result, String methodName) throws TException {
// Read the service response - same as in TServiceClient#receiveBase
TMessage msg = iprot_.readMessageBegin();
if (msg.type == TMessageType.EXCEPTION) {
TApplicationException x = TApplicationException.read(iprot_);
iprot_.readMessageEnd();
throw x;
}
if (msg.seqid != this.seqid_) {
throw new TApplicationException(TApplicationException.BAD_SEQUENCE_ID, methodName + " failed: out of sequence response");
}
result.read(iprot_);
iprot_.readMessageEnd();
// now relay the response to the client
clientProtocol.writeMessageBegin(msg);
result.write(clientProtocol);
clientProtocol.writeMessageEnd();
clientProtocol.getTransport().flush();
LOGGER.debug("Relayed thrift response to client. Seq Id : " + msg.seqid + ", Method : " +msg.name + ", value : " + result);
}
}