Receiving a search intent based on product name and sending list of pharmacies that sell matching items (Java)

In this use case, the user types the name of a pharmaceutical product on a search bar and expects a list of stores that sell the items matching his search. This sort of result appears in the case of retail aggregator BPPs that have onboarded multiple pharmacys on their platform

Code snippets

BPP receives protocol search

/*
Example Request JSON:
{
    "context": {
        "domain": "nic2004:52311",
        "country": "IND",
        "city": "std:080",
        "action": "search",
        "core_version": "0.9.2",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "transaction_id": "1239890342",
        "message_id": "123793824",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "intent": {
            "item": {
                "descriptor": {
                    "name": "Antibiotics"
                }
            },
            "fulfillment": {
                "end": {
                    "location": {
                        "gps": "12.4535445,77.9283792"
                    }
                }
            }
        }
    }
}
*/
    // BPP Search endpoint
    @PostMapping("/bpp/search")
    public ResponseEntity search(
            @RequestHeader HttpHeaders headers,
            @RequestBody SearchRequest request) {
        var response = bppApplicationService.search(request, headers);
        return ResponseEntity.ok(response);
    }

BPP processes the search

    public Response search(SearchRequest request, HttpHeaders headers) {
        var searchResponse = new OnSearchRequest();
        // Validate the headers
        var isHeadersValid = validateHeaders(headers);
        // Construct and return error
        if (!isHeadersValid) return null;

        // Fetch the data based on the request
        var requestIntent = request.getMessage().getIntent();

        // Execute business logic here

        // Generate the response
        searchResponse = generateSearchResponse();

        //invoke on_search api
        return invokeOnSearch(searchResponse, headers);
    }
}

BPP generates response

/*
Example Response JSON:
{
    "context": {
        "domain": "nic2004:52311",
        "country": "IND",
        "city": "std:080",
        "action": "on_search",
        "core_version": "0.9.2",
        "bap_id": "https://mock_bap.com/",
        "bap_uri": "https://mock_bap.com/beckn/",
        "transaction_id": "1239890342",
        "message_id": "123793824",
        "timestamp": "2021-03-23T10:00:40.065Z"
    },
    "message": {
        "catalog": {
            "bpp/descriptor": {
                "name": "Pharma BPP"
            },
            "bpp/providers": [
                {
                    "id": "abc_medicines",
                    "descriptor": {
                        "name": "ABC Medicines"
                    },
                    "locations": [
                        {
                            "id": "abc_medicines_koramangala",
                            "gps": "12.9349377,77.6055586"
                        }
                    ]
                },
                {
                    "id": "good_health",
                    "descriptor": {
                        "name": "Good Health Pharmacy"
                    },
                    "locations": [
                        {
                            "id": "good_health_koramangala",
                            "gps": "12.9349406,77.6208795"
                        }
                    ]
                },
                {
                    "id": "medhealth_pharmacy",
                    "descriptor": {
                        "name": "MedHealth Pharmacy"
                    },
                    "locations": [
                        {
                            "id": "medhealth_pharmacy_koramangala"
                        }
                    ]
                }
            ]
        }
    }
}
*/
    public OnSearchRequest generateSearchResponse(List searchResult) {
        var searchResult = SearchResponseBuilder.builder.result(searchResult).build();
        // Convert response into protocol object similar to example above
        return searchResult;
    }

BPP calls protocol on_search

    public Response invokeOnSearch(OnSearchRequest searchResponse, HttpHeaders headers) {
        if(searchResponse.getError() == null) {
            // Call BAP on_search api with the search response
            var url = lookUp(headers);
            var response = apiClient.post(url[0] + Context.ActionEnum.on_search,
                    constructResponseHeaders(),
                    searchResponse,
                    OnSearchRequest.class);
            return Response.of("ACK", null);
        } else {
            return Response.of("NACK", null);
        }
    }