1. Overview

EzyMosquitto (Easy going to Mosquitto Interaction) is a framework support to interact to Apache Mosquitto, It supports:

RPC (Remote procedure call)
Publish and consume message
Serialize and Deserialize to map message's data in byte array to POJO
Annotation driven

2. Structure of EzyMosquitto

EzyMosquittoProxy: Manages producers, consumers, topics and data serializers.
EzyMosquittoProducer: Supports to send messages and RPC.
EzyMosquittoProducer: Supports to receive, consume the messages and response the RPC result
EzyMosquittoTopic: Supports to send and consume messages via topic

3. Install EzyMosquitto

1. To create EzyMosquitto we need add dependency

<dependency>
    <groupId>com.tvd12</groupId>
    <artifactId>ezymq-mosquitto</artifactId>
    <version>1.2.5</version>
</dependency>

The latest version can be found in the Maven Central repository. You can configure EzyMosquitto like this:

    EzyMosquittoProxy proxy = EzyMosquittoProxy.builder()
        .scan("com.tvd12.ezymq.mosquitto.test")
        .build();

2. You can add to your configuration file like this:

    # for application.yaml
    mosquitto:
      producers:
        test: default
      consumers:
        test: default
      topics:
        hello:
          producer: default
          consumer: default

    # for application.properties
    mosquitto.producers.test=default
    mosquitto.consumers.test=default
    mosquitto.topics.hello.producer=default
    mosquitto.topics.hello.consumer=default

4. Example

Let’s say we need consume a message to sum 2 integer numbers and get the result, we can do it with EzyMosquitto follow by bellow steps.

4.1 Create request/response classes

We need create a request class has 2 fields: a and b:

    package com.tvd12.ezymq.mosquitto.test.request;
    import com.tvd12.ezyfox.message.annotation.EzyMessage;
    import lombok.AllArgsConstructor;
    import lombok.Data;
    import lombok.NoArgsConstructor;
    @Data
    @EzyMessage
    @AllArgsConstructor
    @NoArgsConstructor
    public class SumRequest {
        private int a;
        private int b;
    }

And a response class has 1 field sum:

    package com.tvd12.ezymq.mosquitto.test.response;
    import com.tvd12.ezyfox.message.annotation.EzyMessage;
    import lombok.AllArgsConstructor;
    import lombok.Getter;
    import lombok.ToString;
    @Getter
    @EzyMessage
    @ToString
    @AllArgsConstructor
    public class SumResponse {
        private int sum;
    }

4.2 Create message handler class

Now we need create a handler class to handle the message:

    package com.tvd12.ezymq.mosquitto.test.handler;
    import com.tvd12.ezymq.mosquitto.annotation.EzyMosquittoHandler;
    import com.tvd12.ezymq.mosquitto.handler.EzyMosquittoRequestHandler;
    import com.tvd12.ezymq.mosquitto.test.request.SumRequest;
    import com.tvd12.ezymq.mosquitto.test.response.SumResponse;
    @EzyMosquittoHandler("sum")
    public class SumRequestHandler implements EzyMosquittoRequestHandler {
        @Override
        public Object handle(SumRequest request) {
            return new SumResponse(
                request.getA() + request.getB()
            );
        }
    }

4.3 Create a program for rpc client

We need create a class has main method to start a rpc client:

    package com.tvd12.ezymq.mosquitto.test;
    import com.tvd12.ezymq.mosquitto.EzyMosquittoProxy;
    import com.tvd12.ezymq.mosquitto.EzyMosquittoRpcProducer;
    import com.tvd12.ezymq.mosquitto.test.request.SumRequest;
    import com.tvd12.ezymq.mosquitto.test.response.SumResponse;
    public final class SumRpcClientProgram {
        public static void main(String[] args) {
            final EzyMosquittoProxy proxy = EzyMosquittoProxy
                .builder()
                .scan("com.tvd12.ezymq.mosquitto.test")
                .build();
            final EzyMosquittoRpcProducer producer = proxy.getRpcProducer("test");
            SumResponse sumResponse = producer.call(
                "sum",
                new SumRequest(1, 2),
                SumResponse.class
            );
            System.out.println("sum result: " + sumResponse);
        }
    }

With configration like this:

    # for application.yaml
    mosquitto:
      producers:
        test: default

4.4 Create a program for rpc server

We need create a class has main method to start consumers:

    package com.tvd12.ezymq.mosquitto.test;
    import com.tvd12.ezymq.mosquitto.EzyMosquittoProxy;
    public final class SumRpcServerProgram {
        public static void main(String[] args) {
            EzyMosquittoProxy
                .builder()
                .scan("com.tvd12.ezymq.mosquitto.test")
                .build();
        }
    }

With configration like this:

    # for application.yaml
    mosquitto:
      consumers:
        test: default

4.5 Run the program

Please make sure you have downloaded, installed, and started the Mosquitto broker.

Now run the both SumRpcServerProgram and SumRpcClientProgram programs separately, we will see the log in the SumRpcClientProgram:

sum result: SumResponse(sum=3)

Next step

You can see how to configure.

Introduce EzyMosquitto