DEVX-640: keyResolver for not null

Author: ShipilA

commercetools/commercetools-importapi-utils/src/main/java/com/commercetools/sdk/ExpandObjResolverService.java

@@ -0,0 +1,11 @@
+package com.commercetools.sdk;
+
+import com.commercetools.api.models.IdentifiableObjHolder;
+import com.commercetools.api.models.WithKey;
+
+public class ExpandObjResolverService<T extends IdentifiableObjHolder<TResource>, TResource extends WithKey> implements KeyResolverService<T> {
+
+    public String resolveKey(T identifiable) {
+        return identifiable.getObj().getKey();
+    }
+}

commercetools/commercetools-importapi-utils/src/main/java/com/commercetools/sdk/KeyResolverService.java

@@ -0,0 +1,5 @@
+package com.commercetools.sdk;
+
+public interface KeyResolverService<T> {
+    public String resolveKey(T identifiable);
+}

commercetools/commercetools-importapi-utils/src/main/java/com/commercetools/sdk/ProductUtil.java

@@ -1,11 +1,11 @@
-
 package com.commercetools.sdk;
 
 import java.time.LocalDate;
 import java.time.ZonedDateTime;
 import java.util.*;
 import java.util.stream.Collectors;
 
+import com.commercetools.api.models.category.CategoryReference;
 import com.commercetools.api.models.common.CentPrecisionMoney;
 import com.commercetools.api.models.common.LocalizedString;
 import com.commercetools.api.models.common.Money;
@@ -26,7 +26,11 @@
 import com.commercetools.importapi.models.productvariants.NumberAttribute;
 
 public final class ProductUtil {
+    private static KeyResolverService<CategoryReference> catKeyResolverService;
 
+    public ProductUtil() {
+        catKeyResolverService = new ExpandObjResolverService<>();
+    }
     public static ProductDraftImport toProductDraftImport(ProductProjection product) {
         var draft = ProductDraftImport.builder()
                 .key(product.getKey())
@@ -151,7 +155,7 @@ private static List<com.commercetools.importapi.models.common.Asset> importAsset
     private static List<CategoryKeyReference> extractCategoryKeyReference(ProductProjection product) {
         return product.getCategories()
                 .stream()
-                .map(c -> CategoryKeyReference.builder().key(c.getObj().getKey()).build())
+                .map(c -> CategoryKeyReference.builder().key(catKeyResolverService.resolveKey(c)).build())
                 .collect(Collectors.toList());
     }