ceph/src/jaegertracing/thrift/lib/java/src/org/apache/thrift/protocol/TMultiplexedProtocol.java

   1 /*
   2  * Licensed to the Apache Software Foundation (ASF) under one
   3  * or more contributor license agreements. See the NOTICE file
   4  * distributed with this work for additional information
   5  * regarding copyright ownership. The ASF licenses this file
   6  * to you under the Apache License, Version 2.0 (the
   7  * "License"); you may not use this file except in compliance
   8  * with the License. You may obtain a copy of the License at
   9  *
  10  *   http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  * Unless required by applicable law or agreed to in writing,
  13  * software distributed under the License is distributed on an
  14  * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
  15  * KIND, either express or implied. See the License for the
  16  * specific language governing permissions and limitations
  17  * under the License.
  18  */
  19
  20 package org.apache.thrift.protocol;
  21
  22 import org.apache.thrift.TException;
  23
  24 /**
  25  * <code>TMultiplexedProtocol</code> is a protocol-independent concrete decorator
  26  * that allows a Thrift client to communicate with a multiplexing Thrift server,
  27  * by prepending the service name to the function name during function calls.
  28  *
  29  * <p>NOTE: THIS IS NOT USED BY SERVERS.  On the server, use {@link org.apache.thrift.TMultiplexedProcessor TMultiplexedProcessor} to handle requests
  30  * from a multiplexing client.
  31  *
  32  * <p>This example uses a single socket transport to invoke two services:
  33  *
  34  * <pre>
  35  * {@code
  36  *     TSocket transport = new TSocket("localhost", 9090);
  37  *     transport.open();
  38  *
  39  *     TBinaryProtocol protocol = new TBinaryProtocol(transport);
  40  *
  41  *     TMultiplexedProtocol mp = new TMultiplexedProtocol(protocol, "Calculator");
  42  *     Calculator.Client service = new Calculator.Client(mp);
  43  *
  44  *     TMultiplexedProtocol mp2 = new TMultiplexedProtocol(protocol, "WeatherReport");
  45  *     WeatherReport.Client service2 = new WeatherReport.Client(mp2);
  46  *
  47  *     System.out.println(service.add(2,2));
  48  *     System.out.println(service2.getTemperature());
  49  * }
  50  * </pre>
  51  *
  52  * @see org.apache.thrift.protocol.TProtocolDecorator
  53  */
  54 public class TMultiplexedProtocol extends TProtocolDecorator {
  55
  56     /** Used to delimit the service name from the function name */
  57     public static final String SEPARATOR = ":";
  58
  59     private final String SERVICE_NAME;
  60
  61     /**
  62      * Wrap the specified protocol, allowing it to be used to communicate with a
  63      * multiplexing server.  The <code>serviceName</code> is required as it is
  64      * prepended to the message header so that the multiplexing server can broker
  65      * the function call to the proper service.
  66      *
  67      * @param protocol Your communication protocol of choice, e.g. <code>TBinaryProtocol</code>.
  68      * @param serviceName The service name of the service communicating via this protocol.
  69      */
  70     public TMultiplexedProtocol(TProtocol protocol, String serviceName) {
  71         super(protocol);
  72         SERVICE_NAME = serviceName;
  73     }
  74
  75     /**
  76      * Prepends the service name to the function name, separated by TMultiplexedProtocol.SEPARATOR.
  77      *
  78      * @param tMessage The original message.
  79      * @throws TException Passed through from wrapped <code>TProtocol</code> instance.
  80      */
  81     @Override
  82     public void writeMessageBegin(TMessage tMessage) throws TException {
  83         if (tMessage.type == TMessageType.CALL || tMessage.type == TMessageType.ONEWAY) {
  84             super.writeMessageBegin(new TMessage(
  85                     SERVICE_NAME + SEPARATOR + tMessage.name,
  86                     tMessage.type,
  87                     tMessage.seqid
  88             ));
  89         } else {
  90             super.writeMessageBegin(tMessage);
  91         }
  92     }
  93 }