Fix desktop ProductSupplier to use composite keys

- Remove id field from ProductSupplierResponse
- Rename supplierPrice to cost in ProductSupplierResponse and ProductSupplierRequest
- Update ProductSupplierApi to use composite keys (productId, supplierId) for update and delete
- Update ProductSupplierController delete logic to iterate and delete with composite keys
- Update ProductSupplierController mapping to use getCost() instead of getSupplierPrice()
- Update ProductSupplierDialogController to pass both productId and supplierId to update
- Update ProductSupplierDialogController to use setCost() instead of setSupplierPrice()
- Remove unused selectedId field from ProductSupplierDialogController

src/main/java/org/example/petshopdesktop/api/dto/adoption/AdoptionRequest.java

@@ -8,6 +8,9 @@ public class AdoptionRequest {
     private LocalDate adoptionDate;
     private String adoptionStatus;
 
+    public AdoptionRequest() {
+    }
+
     public Long getPetId() {
         return petId;
     }

src/main/java/org/example/petshopdesktop/api/dto/adoption/AdoptionResponse.java

@@ -9,6 +9,9 @@ public class AdoptionResponse {
     private LocalDate adoptionDate;
     private String adoptionStatus;
 
+    public AdoptionResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/analytics/DailySales.java

@@ -7,6 +7,9 @@ public class DailySales {
     private LocalDate date;
     private BigDecimal totalSales;
 
+    public DailySales() {
+    }
+
     public LocalDate getDate() {
         return date;
     }

src/main/java/org/example/petshopdesktop/api/dto/analytics/DashboardResponse.java

@@ -11,6 +11,9 @@ public class DashboardResponse {
     private List<DailySales> dailySales;
     private List<TopProduct> topProducts;
 
+    public DashboardResponse() {
+    }
+
     public BigDecimal getTotalRevenue() {
         return totalRevenue;
     }

src/main/java/org/example/petshopdesktop/api/dto/analytics/TopProduct.java

@@ -7,6 +7,9 @@ public class TopProduct {
     private Integer quantitySold;
     private BigDecimal totalRevenue;
 
+    public TopProduct() {
+    }
+
     public String getProductName() {
         return productName;
     }

src/main/java/org/example/petshopdesktop/api/dto/appointment/AppointmentRequest.java

@@ -12,6 +12,9 @@ public class AppointmentRequest {
     private LocalTime appointmentTime;
     private String appointmentStatus;
 
+    public AppointmentRequest() {
+    }
+
     public List<Long> getPetIds() {
         return petIds;
     }

src/main/java/org/example/petshopdesktop/api/dto/appointment/AppointmentResponse.java

@@ -12,6 +12,9 @@ public class AppointmentResponse {
     private LocalTime appointmentTime;
     private String appointmentStatus;
 
+    public AppointmentResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/auth/LoginResponse.java

@@ -5,6 +5,9 @@ public class LoginResponse {
     private String username;
     private String role;
 
+    public LoginResponse() {
+    }
+
     public String getToken() {
         return token;
     }

src/main/java/org/example/petshopdesktop/api/dto/auth/UserInfoResponse.java

@@ -5,6 +5,9 @@ public class UserInfoResponse {
     private String username;
     private String role;
 
+    public UserInfoResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/common/DropdownOption.java

@@ -4,6 +4,9 @@ public class DropdownOption {
     private Long id;
     private String label;
 
+    public DropdownOption() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/common/PageResponse.java

@@ -1,15 +1,27 @@
 package org.example.petshopdesktop.api.dto.common;
 
+import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
 import java.util.List;
 
+@JsonIgnoreProperties(ignoreUnknown = true)
 public class PageResponse<T> {
     private List<T> content;
+
+    @JsonProperty("number")
     private int pageNumber;
+
+    @JsonProperty("size")
     private int pageSize;
+
     private long totalElements;
     private int totalPages;
     private boolean last;
 
+    public PageResponse() {
+    }
+
     public List<T> getContent() {
         return content;
     }

src/main/java/org/example/petshopdesktop/api/dto/inventory/InventoryRequest.java

@@ -6,6 +6,9 @@ public class InventoryRequest {
     private Integer stockQuantity;
     private Integer reorderLevel;
 
+    public InventoryRequest() {
+    }
+
     public Long getProductId() {
         return productId;
     }

src/main/java/org/example/petshopdesktop/api/dto/inventory/InventoryResponse.java

@@ -8,6 +8,9 @@ public class InventoryResponse {
     private Integer stockQuantity;
     private Integer reorderLevel;
 
+    public InventoryResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/pet/PetRequest.java

@@ -13,6 +13,9 @@ public class PetRequest {
     private BigDecimal price;
     private String petStatus;
 
+    public PetRequest() {
+    }
+
     public String getPetName() {
         return petName;
     }

src/main/java/org/example/petshopdesktop/api/dto/pet/PetResponse.java

@@ -14,6 +14,9 @@ public class PetResponse {
     private BigDecimal price;
     private String petStatus;
 
+    public PetResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/product/ProductRequest.java

@@ -8,6 +8,9 @@ public class ProductRequest {
     private BigDecimal price;
     private String description;
 
+    public ProductRequest() {
+    }
+
     public String getProductName() {
         return productName;
     }

src/main/java/org/example/petshopdesktop/api/dto/product/ProductResponse.java

@@ -9,6 +9,9 @@ public class ProductResponse {
     private BigDecimal price;
     private String description;
 
+    public ProductResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/productsupplier/ProductSupplierRequest.java

@@ -5,7 +5,10 @@ import java.math.BigDecimal;
 public class ProductSupplierRequest {
     private Long productId;
     private Long supplierId;
-    private BigDecimal supplierPrice;
+    private BigDecimal cost;
+
+    public ProductSupplierRequest() {
+    }
 
     public Long getProductId() {
         return productId;
@@ -23,11 +26,11 @@ public class ProductSupplierRequest {
         this.supplierId = supplierId;
     }
 
-    public BigDecimal getSupplierPrice() {
-        return supplierPrice;
+    public BigDecimal getCost() {
+        return cost;
     }
 
-    public void setSupplierPrice(BigDecimal supplierPrice) {
-        this.supplierPrice = supplierPrice;
+    public void setCost(BigDecimal cost) {
+        this.cost = cost;
     }
 }

src/main/java/org/example/petshopdesktop/api/dto/productsupplier/ProductSupplierResponse.java

@@ -3,19 +3,13 @@ package org.example.petshopdesktop.api.dto.productsupplier;
 import java.math.BigDecimal;
 
 public class ProductSupplierResponse {
-    private Long id;
     private Long productId;
     private Long supplierId;
     private String productName;
     private String supplierName;
-    private BigDecimal supplierPrice;
+    private BigDecimal cost;
 
-    public Long getId() {
-        return id;
-    }
-
-    public void setId(Long id) {
-        this.id = id;
+    public ProductSupplierResponse() {
     }
 
     public Long getProductId() {
@@ -50,11 +44,11 @@ public class ProductSupplierResponse {
         this.supplierName = supplierName;
     }
 
-    public BigDecimal getSupplierPrice() {
-        return supplierPrice;
+    public BigDecimal getCost() {
+        return cost;
     }
 
-    public void setSupplierPrice(BigDecimal supplierPrice) {
-        this.supplierPrice = supplierPrice;
+    public void setCost(BigDecimal cost) {
+        this.cost = cost;
     }
 }

src/main/java/org/example/petshopdesktop/api/dto/purchaseorder/PurchaseOrderResponse.java

@@ -11,6 +11,9 @@ public class PurchaseOrderResponse {
     private String orderStatus;
     private BigDecimal totalAmount;
 
+    public PurchaseOrderResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/sale/SaleItemRequest.java

@@ -7,6 +7,9 @@ public class SaleItemRequest {
     private Integer quantity;
     private BigDecimal unitPrice;
 
+    public SaleItemRequest() {
+    }
+
     public Long getProductId() {
         return productId;
     }

src/main/java/org/example/petshopdesktop/api/dto/sale/SaleItemResponse.java

@@ -9,6 +9,9 @@ public class SaleItemResponse {
     private BigDecimal unitPrice;
     private BigDecimal lineTotal;
 
+    public SaleItemResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/sale/SaleRequest.java

@@ -9,6 +9,9 @@ public class SaleRequest {
     private Boolean isRefund;
     private Long originalSaleId;
 
+    public SaleRequest() {
+    }
+
     public Long getStoreId() {
         return storeId;
     }

src/main/java/org/example/petshopdesktop/api/dto/sale/SaleResponse.java

@@ -15,6 +15,9 @@ public class SaleResponse {
     private Long originalSaleId;
     private List<SaleItemResponse> items;
 
+    public SaleResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/service/ServiceRequest.java

@@ -7,6 +7,9 @@ public class ServiceRequest {
     private BigDecimal price;
     private String description;
 
+    public ServiceRequest() {
+    }
+
     public String getServiceName() {
         return serviceName;
     }

src/main/java/org/example/petshopdesktop/api/dto/service/ServiceResponse.java

@@ -8,6 +8,9 @@ public class ServiceResponse {
     private BigDecimal price;
     private String description;
 
+    public ServiceResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/supplier/SupplierRequest.java

@@ -7,6 +7,9 @@ public class SupplierRequest {
     private String email;
     private String address;
 
+    public SupplierRequest() {
+    }
+
     public String getSupplierName() {
         return supplierName;
     }

src/main/java/org/example/petshopdesktop/api/dto/supplier/SupplierResponse.java

@@ -8,6 +8,9 @@ public class SupplierResponse {
     private String email;
     private String address;
 
+    public SupplierResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/dto/user/UserRequest.java

@@ -8,6 +8,9 @@ public class UserRequest {
     private String role;
     private Boolean active;
 
+    public UserRequest() {
+    }
+
     public String getUsername() {
         return username;
     }

src/main/java/org/example/petshopdesktop/api/dto/user/UserResponse.java

@@ -10,6 +10,9 @@ public class UserResponse {
     private Boolean active;
     private LocalDateTime createdAt;
 
+    public UserResponse() {
+    }
+
     public Long getId() {
         return id;
     }

src/main/java/org/example/petshopdesktop/api/endpoints/ProductSupplierApi.java

@@ -43,11 +43,11 @@ public class ProductSupplierApi {
         return apiClient.post("/api/v1/product-suppliers", request, ProductSupplierResponse.class);
     }
 
-    public ProductSupplierResponse updateProductSupplier(Long id, ProductSupplierRequest request) throws Exception {
-        return apiClient.put("/api/v1/product-suppliers/" + id, request, ProductSupplierResponse.class);
+    public ProductSupplierResponse updateProductSupplier(Long productId, Long supplierId, ProductSupplierRequest request) throws Exception {
+        return apiClient.put("/api/v1/product-suppliers/" + productId + "/" + supplierId, request, ProductSupplierResponse.class);
     }
 
-    public void deleteProductSuppliers(List<Long> ids) throws Exception {
-        apiClient.deleteWithBody("/api/v1/product-suppliers", new BulkDeleteRequest(ids));
+    public void deleteProductSupplier(Long productId, Long supplierId) throws Exception {
+        apiClient.delete("/api/v1/product-suppliers/" + productId + "/" + supplierId);
     }
 }

src/main/java/org/example/petshopdesktop/controllers/ProductSupplierController.java

@@ -192,24 +192,36 @@ public class ProductSupplierController {
 
         //if confirmed, start deletion
         if (result.isPresent() && result.get() == ButtonType.OK) {
-            List<Long> ids = selectedProductSuppliers.stream()
-                .map(ps -> (long) ps.getSupId())
-                .collect(Collectors.toList());
+            int deleteCount = 0;
+            Exception lastException = null;
 
-            try {
-                ProductSupplierApi.getInstance().deleteProductSuppliers(ids);
+            for (ProductSupplierDTO ps : selectedProductSuppliers) {
+                try {
+                    ProductSupplierApi.getInstance().deleteProductSupplier(
+                        (long) ps.getProdId(),
+                        (long) ps.getSupId()
+                    );
+                    deleteCount++;
+                } catch (Exception e) {
+                    lastException = e;
+                    ActivityLogger.getInstance().logException(
+                        "ProductSupplierController.btnDeleteClicked",
+                        e,
+                        "Deleting product-supplier with productId=" + ps.getProdId() + ", supplierId=" + ps.getSupId());
+                }
+            }
+
+            if (deleteCount > 0) {
                 Alert alert = new Alert(Alert.AlertType.INFORMATION);
                 alert.setHeaderText("Database Operation Confirmed");
-                alert.setContentText("Successfully deleted " + ids.size() + " product-supplier(s)");
+                alert.setContentText("Successfully deleted " + deleteCount + " product-supplier(s)");
                 alert.showAndWait();
-            } catch (Exception e) {
-                ActivityLogger.getInstance().logException(
-                    "ProductSupplierController.btnDeleteClicked",
-                    e,
-                    "Deleting product-suppliers");
+            }
+
+            if (lastException != null && deleteCount < selectedProductSuppliers.size()) {
                 Alert alert = new Alert(Alert.AlertType.ERROR);
-                alert.setHeaderText("Delete Operation Failed");
-                alert.setContentText(e.getMessage());
+                alert.setHeaderText("Delete Operation Partially Failed");
+                alert.setContentText("Deleted " + deleteCount + " of " + selectedProductSuppliers.size() + " product-supplier(s). Last error: " + lastException.getMessage());
                 alert.showAndWait();
             }
 
@@ -286,7 +298,7 @@ public class ProductSupplierController {
             response.getProductId().intValue(),
             response.getSupplierName(),
             response.getProductName(),
-            response.getSupplierPrice().doubleValue()
+            response.getCost().doubleValue()
         );
     }
 

src/main/java/org/example/petshopdesktop/controllers/dialogcontrollers/ProductSupplierDialogController.java

@@ -46,7 +46,6 @@ public class ProductSupplierDialogController {
     private String mode = null;
     private int selectedSupId = -1;
     private int selectedProdId = -1;
-    private Long selectedId = null;
 
     /**
      * add event listeners to buttons and set up combobox
@@ -169,7 +168,7 @@ public class ProductSupplierDialogController {
                     if (mode.equals("Add")) {
                         ProductSupplierApi.getInstance().createProductSupplier(request);
                     } else {
-                        ProductSupplierApi.getInstance().updateProductSupplier(selectedId, request);
+                        ProductSupplierApi.getInstance().updateProductSupplier((long) selectedProdId, (long) selectedSupId, request);
                     }
 
                     Platform.runLater(() -> {
@@ -209,7 +208,7 @@ public class ProductSupplierDialogController {
         request.setSupplierId(cbSupplier.getSelectionModel().getSelectedItem().getId());
         request.setProductId(cbProduct.getSelectionModel().getSelectedItem().getId());
         try {
-            request.setSupplierPrice(new BigDecimal(txtCost.getText()));
+            request.setCost(new BigDecimal(txtCost.getText()));
         } catch (NumberFormatException e) {
             throw new IllegalArgumentException("Invalid cost format");
         }
@@ -266,7 +265,6 @@ public class ProductSupplierDialogController {
     public void setSelectedIds(int supId, int prodId){
         this.selectedSupId = supId;
         this.selectedProdId = prodId;
-        this.selectedId = (long) supId;
     }
 
 }