Build The Web Layer

Implementing the controller layer in Spring

Overview

The web/controller layer handles all the incoming REST requests to a service.

Steps

The @RequestMapping("/v1") annotation is added on top of the controller class. This contains the version of the API (this becomes a part of the API endpoint URL).

Steps to setup the request handler in the controller layer

Follow the steps below to set up the request handler in the controller layer.

1. Make a call to the method in the Service Layer and get the response back from it.

2. Build the responseInfo.

3. Build the final response to be returned to the client.

Sample request handler in controller layer

The controller class here contains the below content -

package digit.web.controllers;

import com.fasterxml.jackson.databind.ObjectMapper;
import digit.service.BirthRegistrationService;
import digit.utils.ResponseInfoFactory;
import digit.web.models.*;
import io.swagger.annotations.ApiParam;
import io.swagger.annotations.Tag;
import lombok.ToString;
import lombok.extern.slf4j.Slf4j;
import org.egov.common.contract.response.ResponseInfo;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.http.HttpStatus;
import org.springframework.http.ResponseEntity;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.ModelAttribute;
import org.springframework.web.bind.annotation.RequestBody;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

import javax.servlet.http.HttpServletRequest;
import javax.validation.Valid;
import java.util.Collections;
import java.util.List;
@javax.annotation.Generated(value = "org.egov.codegen.SpringBootCodegen", date = "2022-07-26T12:39:05.988+05:30")
@Slf4j
@ToString
@Controller
@RequestMapping("/birth-services")
public class V1ApiController{

    private final ObjectMapper objectMapper;

    private final HttpServletRequest request;

    private BirthRegistrationService birthRegistrationService;

    @Autowired
    private ResponseInfoFactory responseInfoFactory;

    @Autowired
    public V1ApiController(ObjectMapper objectMapper, HttpServletRequest request, BirthRegistrationService birthRegistrationService) {
        this.objectMapper = objectMapper;
        this.request = request;
        this.birthRegistrationService = birthRegistrationService;
    }

    @RequestMapping(value="/v1/registration/_create", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationCreatePost(@ApiParam(value = "Details for the new Birth Registration Application(s) + RequestInfo meta data." ,required=true )  @Valid @RequestBody BirthRegistrationRequest birthRegistrationRequest) {
        List<BirthRegistrationApplication> applications = birthRegistrationService.registerBtRequest(birthRegistrationRequest);
        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(birthRegistrationRequest.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(applications).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response, HttpStatus.OK);
    }

    @RequestMapping(value="/v1/registration/_search", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationSearchPost(@RequestBody RequestInfoWrapper requestInfoWrapper, @Valid @ModelAttribute BirthApplicationSearchCriteria birthApplicationSearchCriteria) {
        List<BirthRegistrationApplication> applications = birthRegistrationService.searchBtApplications(requestInfoWrapper.getRequestInfo(), birthApplicationSearchCriteria);
        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(requestInfoWrapper.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(applications).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response,HttpStatus.OK);
    }

    @RequestMapping(value="/v1/registration/_update", method = RequestMethod.POST)
    public ResponseEntity<BirthRegistrationResponse> v1RegistrationUpdatePost(@ApiParam(value = "Details for the new (s) + RequestInfo meta data." ,required=true )  @Valid @RequestBody BirthRegistrationRequest birthRegistrationRequest) {
        BirthRegistrationApplication application = birthRegistrationService.updateBtApplication(birthRegistrationRequest);

        ResponseInfo responseInfo = responseInfoFactory.createResponseInfoFromRequestInfo(birthRegistrationRequest.getRequestInfo(), true);
        BirthRegistrationResponse response = BirthRegistrationResponse.builder().birthRegistrationApplications(Collections.singletonList(application)).responseInfo(responseInfo).build();
        return new ResponseEntity<>(response, HttpStatus.OK);
    }

}

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.

4. Since the Codegen jar creates the search API with search parameters annotated with @RequestParam rather than taking request parameters as a POJO. For this, we will create a POJO by the name of BirthApplicationSearchCriteria within the Models package. Insert the following content in POJO.

package digit.web.models;

import com.fasterxml.jackson.annotation.JsonProperty;
import lombok.*;

import java.util.List;

@Data
@Getter
@Setter
@AllArgsConstructor
@NoArgsConstructor
@Builder
@ToString
public class BirthApplicationSearchCriteria {

    @JsonProperty("tenantId")
    private String tenantId;

    @JsonProperty("status")
    private String status;

    @JsonProperty("ids")
    private List<String> ids;

    @JsonProperty("applicationNumber")
    private String applicationNumber;

}

The web layer is now setup.