Tuesday, May 9, 2017

Lead Microservice - Add the service and controller

This post continues from the last one. I will try to complete the lead microservice in this post. I will be focusing primarily on the CRUD operation. In CRM applications, that is the primary set of operations.
I will start by creating the exception class. Later I would show how to use this exception class and Spring Rest exception handling and build a robust error handling around the API calls.
Listing 1 - BusinessException.java

Next step would be to introduce the service class. Since this is CRUD most of the functionality can be encapsulated in an abstract parent service class. Any specific feature like convert lead to opportunity can be implemented in the LeadService class.

Listing 2 - AbstractBaseBusinessDelegate.java
And then finally the LeadService implementation class is shown in Listing 3.

Listing 3 - LeadBusinessDelegate.java
Note that this code will not compile. In order to get this to compile, you will need to add 2 new dependencies for the Jodd libraries. Jodd is a popular micro framework which provides very useful utilities and lightweight framework to develop Java applications.

Listing 4 - build.gradle snippet

Now I am going to add the Spring Rest controller. This class is responsible for handling all microservices call. It then delegates to the business delegate to complete the business operation. As you must have already noted, the business delegate then calls repository to retrieve any data from the backing data store. In this series, I am using JPA store or my code is interacting with a relational database. Later I intend to add NoSQL store also and show if and how they can reside together.
Just like the business delegate most of the functionality is encapsulated in the base controller class as shown in Listing 5.

Listing 5 - AbstractBaseController.java
And finally here is the LeadController implementation class in Listing 6.

Listing 6 - LeadController.java

Thats all for now. The source code is available on Github repository

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