json-api-invoker

Backgroud

Many services have expose some specific JSON messages as the API protocol.

1. One service/client send a JSON message to another service for RPC.

2. The other serice receives a JSON message to invoke some specific logic inside the service.

Motivation

To avoid parse the JSON message each time manually:

1. Create a framework that can parse the JSON message according the some specific model.

2. The framework can parse the JSON message, and invoke a specific logic inside the service.

3. Implement something just the Spring annotation framework(@Controller, @Component, etc).

Design

1. Message model definition:

In common designs, the message contain two parts: Header and Body.

--The Header contains the information like 'requestId', 'sourceId', 'originalId' which are used to identify the caller, the source and sender.

--The Body contains the message data, that the service will used to invoke a specific logic.

So, the lib provided the annotations below for model definition:

@APIComponentDefinition, @APIDefinition, @APIParametersDefinition, @APIParameterDefinition, @APIHeaderDefinition

A sample message model might be:

  public class MessageModel {

    @APIHeaderDefinition

    private String requestId;      

    private MessageBody body;

    // getters for each field

    private class MessageBody {

      @APIComponentDefinition

      private String command;

      private MessageContent content;

      // getters for each field

      private class MessageContent {
      
        @APIDefinition
        
        private String actionName;

        @APIParametersDefinition

        private Map<String, Object> paramterMap;

        @APIParametersDefinition

        private ParametersSampeModel paramterModel;

        @APIParameterDefinition

        private SingleParameterModel singleParameterModel;

        // getters for the fields

      }
    }  
  }

2. Invoke strategy:

1. The framework will parse the message model, and find the @APIComponentDefintion, @APIDefinition, @APIParametersDefintion, etc.

2. Then it will scan a basepackage to find the compoents with the annotation: @APIComponent,

3. It will invoke the most match @API, inside each @APICompoent.

3. Work flow

   

Demo

Check a details demo under the package **.Sample