Implement Service Layer

Overview

The service layer performs business logic on the RequestData and prepares the Response to be returned back to the client.

Steps

Follow the steps below to create the service layer.

1. Create a new package called Service.

2. Create a new class in this folder by the name BirthRegistrationService.

3. Annotate the class with @Service annotation.

4. Add the following content to the class -

package digit.service;


import digit.enrichment.BirthApplicationEnrichment;
import digit.kafka.Producer;
import digit.repository.BirthRegistrationRepository;
import digit.validators.BirthApplicationValidator;
import digit.web.models.BirthApplicationSearchCriteria;
import digit.web.models.BirthRegistrationApplication;
import digit.web.models.BirthRegistrationRequest;
import digit.web.models.FatherApplicant;
import lombok.extern.slf4j.Slf4j;
import org.egov.common.contract.request.RequestInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.util.CollectionUtils;

import java.util.ArrayList;
import java.util.Collections;
import java.util.List;

@Service
@Slf4j
public class BirthRegistrationService {

    @Autowired
    private BirthApplicationValidator validator;

    @Autowired
    private BirthApplicationEnrichment enrichmentUtil;

    @Autowired
    private UserService userService;

    @Autowired
    private WorkflowService workflowService;

    @Autowired
    private BirthRegistrationRepository birthRegistrationRepository;

    @Autowired
    private Producer producer;

    public List<BirthRegistrationApplication> registerBtRequest(BirthRegistrationRequest birthRegistrationRequest) {
        // Validate applications
        validator.validateBirthApplication(birthRegistrationRequest);

        // Enrich applications
        enrichmentUtil.enrichBirthApplication(birthRegistrationRequest);

        // Enrich/Upsert user in upon birth registration
        userService.callUserService(birthRegistrationRequest);

        // Initiate workflow for the new application
        workflowService.updateWorkflowStatus(birthRegistrationRequest);

        // Push the application to the topic for persister to listen and persist
        producer.push("save-bt-application", birthRegistrationRequest);

        // Return the response back to user
        return birthRegistrationRequest.getBirthRegistrationApplications();
    }

    public List<BirthRegistrationApplication> searchBtApplications(RequestInfo requestInfo, BirthApplicationSearchCriteria birthApplicationSearchCriteria) {
        // Fetch applications from database according to the given search criteria
        List<BirthRegistrationApplication> applications = birthRegistrationRepository.getApplications(birthApplicationSearchCriteria);

        // If no applications are found matching the given criteria, return an empty list
        if(CollectionUtils.isEmpty(applications))
            return new ArrayList<>();

        // Enrich mother and father of applicant objects
        applications.forEach(application -> {
            enrichmentUtil.enrichFatherApplicantOnSearch(application);
            enrichmentUtil.enrichMotherApplicantOnSearch(application);
        });

        // Otherwise return the found applications
        return applications;
    }

    public BirthRegistrationApplication updateBtApplication(BirthRegistrationRequest birthRegistrationRequest) {
        // Validate whether the application that is being requested for update indeed exists
        BirthRegistrationApplication existingApplication = validator.validateApplicationExistence(birthRegistrationRequest.getBirthRegistrationApplications().get(0));
        existingApplication.setWorkflow(birthRegistrationRequest.getBirthRegistrationApplications().get(0).getWorkflow());
        log.info(existingApplication.toString());
        birthRegistrationRequest.setBirthRegistrationApplications(Collections.singletonList(existingApplication));

        // Enrich application upon update
        enrichmentUtil.enrichBirthApplicationUponUpdate(birthRegistrationRequest);

        workflowService.updateWorkflowStatus(birthRegistrationRequest);

        // Just like create request, update request will be handled asynchronously by the persister
        producer.push("update-bt-application", birthRegistrationRequest);

        return birthRegistrationRequest.getBirthRegistrationApplications().get(0);
    }
}

NOTE: At this point, your IDE must be showing a lot of errors but do not worry we will add all dependent layers as we progress through this guide and the errors will go away.