Receiving a search intent based on product name and sending a list of items that match the name (Java)

In this use case, the user types the name of a product on a search bar and expects a list of items that match his search. This usually happens when there is just a single seller catalog published a BPP

Code snippets

BPP receives protocol search

/*
Example Request JSON:
{
    "context": {
        "domain": "local_retail",
        "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" : "Bread and Milk"
                }
            },
            "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": "local_retail",
        "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": "2021-06-23T09:53:38.872Z"
    },
    "message": {
        "catalog": {
            "bpp/descriptor": {
                "name": "Shop EZ"
            },
            "bpp/providers": [
                {
                    "id": "./retail.kirana/ind.blr/[email protected]",
                    "descriptor" : {
                        "name": "Pooja Stores"
                    },
                    "locations": [
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]_location",
                            "gps": "12.9349377,77.6055586"
                        }
                    ],
                    "categories": [
                        {
                            "id": "/local-retail.kirana/ind.blr/[email protected]_category",
                            "descriptor": {
                                "name": "Breads"
                            }
                        },
                        {
                            "id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "descriptor": {
                                "name": "Diary"
                            }
                        }
                    ],
                    "items": [
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]",
                            "descriptor" : {
                                "name" : "Brown Bread 400 gm"
                            },
                            "category_id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "location_id": "./retail.kirana/ind.blr/[email protected]_location",
                            "price" : {
                                "currency": "INR",
                                "value": "40"
                            },
                            "matched": true
                        },
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]",
                            "descriptor" : {
                                "name" : "Good Life Toned Milk 1L"
                            },
                            "category_id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "location_id": "./retail.kirana/ind.blr/[email protected]_location",
                            "price" : {
                                "currency": "INR",
                                "value": "60"
                            },
                            "matched": true
                        }
                    ]
                },
                {
                    "id": "./retail.kirana/ind.blr/[email protected]",
                    "descriptor": {
                        "name": "Food Mall"
                    },
                    "locations": [
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]_location",
                            "gps": "12.9349377,77.6055586"
                        }
                    ],
                    "categories": [
                        {
                            "id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "descriptor": {
                                "name": "Packed goods"
                            }
                        }
                    ],
                    "items": [
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]",
                            "descriptor" : {
                                "name" : "Brown Bread 400 gm"
                            },
                            "category_id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "location_id": "./retail.kirana/ind.blr/[email protected]_location",
                            "price" : {
                                "currency": "INR",
                                "value": "40"
                            },
                            "matched": true
                        },
                        {
                            "id": "./retail.kirana/ind.blr/[email protected]",
                            "descriptor" : {
                                "name" : "Good Life Toned Milk 1L"
                            },
                            "category_id": "./local-retail.kirana/ind.blr/[email protected]_category",
                            "location_id": "./retail.kirana/ind.blr/[email protected]_location",
                            "price" : {
                                "currency": "INR",
                                "value": "60"
                            },
                            "matched": true
                        }
                    ]
                }
            ]
        }
    }
}
*/
    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);
        }
    }