Data retourneren met Jackson

ListResource.java

package week4.college7.bigshopper.shopping.webservices;

import week4.college7.bigshopper.shopping.helpers.SimpleShoppingListResponse;
import week4.college7.bigshopper.shopping.model.Shop;
import week4.college7.bigshopper.shopping.model.ShoppingList;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import javax.ws.rs.core.Response;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.stream.Collectors;

@Path("list")
public class ListResource {

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getShoppingLists()
    {
        // Pak alle shopping lists
        List<ShoppingList> shoppingLists = Shop.getShop().getAllShoppingLists();
        
        // Return error response met Map.of()
        if(shoppingLists.isEmpty()) {

            // https://stackoverflow.com/questions/6802483/how-to-directly-initialize-a-hashmap-in-a-literal-way
            Map<String, String> errorObject = Map.of("error", "no lists present");

            return Response.ok(errorObject).build();
        }
        
        // Return de shopping lists
        return Response.ok(shoppingLists).build();
        
        // ... of:

        // Mapping met map() naar SimpleShoppingListResponse
        List<SimpleShoppingListResponse> responseObjects = shoppingLists.stream().map(
                shoppingList -> SimpleShoppingListResponse.fromShoppingList(shoppingList)
        ).collect(Collectors.toUnmodifiableList());

        return Response.ok(responseObjects).build();
    }

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    @Path("{name}")
    public Response getShoppingListByName(@PathParam("name") String name)
    {
        ShoppingList list = Shop.getShop().getShoppingListByName(name);

        if(list == null) {
            return Response.ok(Map.of("error", "no list by that name")).build();
        }

        return Response.ok(list).build();
    }
}

PersonResource.java

// ...

@Path("shopper")
public class PersonResource {

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public List<Shopper> getShoppers() {
        return Shop.getShop().getAllPersons();
    }

    // ...
}

ProductResource.java

// ...

@Path("product")
public class ProductResource {

    @GET
    @Produces(MediaType.APPLICATION_JSON)
    public Response getProducts() {
        List<Product> products = Shop.getShop().getAllProducts();

        if(products.isEmpty()) {
            return Response.ok(Map.of("error", "no products available")).build();
        }

        // Transformeer lijst van objecten naar lijst van strings met map()
        List<String> productNames = products.stream().map(product -> product.getName()).collect(Collectors.toList());
        return Response.ok(productNames).build();
    }
}

SimpleShoppingListResponse.java

package week4.college7.bigshopper.shopping.helpers;

import javassist.Loader;
import week4.college7.bigshopper.shopping.model.Item;
import week4.college7.bigshopper.shopping.model.ShoppingList;

import java.util.List;

public class SimpleShoppingListResponse {
    public String name;
    public String owner;
    public List<Item> listItems;

    private SimpleShoppingListResponse(String name, String owner, List<Item> listItems) {
        this.name = name;
        this.owner = owner;
        this.listItems = listItems;
    }

    public static SimpleShoppingListResponse fromShoppingList(ShoppingList shoppingList) {
        SimpleShoppingListResponse responseObject = new SimpleShoppingListResponse(
                shoppingList.getName(),
                shoppingList.getOwner().getName(),
                shoppingList.getListItems()
        );

        return responseObject;
    }
}