Added Product mapping and validation

src/main/java/de/rwu/easydrop/service/mapping/ProductMapper.java

@@ -1,14 +1,44 @@
 package de.rwu.easydrop.service.mapping;
 
+import de.rwu.easydrop.api.dto.ProductDTO;
+import de.rwu.easydrop.model.Product;
+
 /**
  * Maps between Product, ProductDAO and ProductDTO.
  *
- * TODO implement
+ * @since 0.2.0
  *
  * @see Product
  * @see ProductDTO
  * @see ProductDAO
  */
-public class ProductMapper {
+public final class ProductMapper {
 
+    /**
+     * Private constructor to prevent unwanted instantiation.
+     *
+     * @throws UnsupportedOperationException always
+     */
+    private ProductMapper() throws UnsupportedOperationException {
+        throw new UnsupportedOperationException("This is a mapping class, don't instantiate it.");
+    }
+
+    /**
+     * Creates a Product object from a corresponding DTO.
+     *
+     * @param dto Product Data Transfer Object
+     * @return Product
+     */
+    public static Product mapProductFromDTO(final ProductDTO dto) {
+        Product product = new Product();
+
+        product.setAvailable(dto.isAvailable());
+        product.setCurrentPrice(dto.getCurrentPrice());
+        product.setDataOrigin(dto.getDataOrigin());
+        product.setDeliveryPrice(dto.getDeliveryPrice());
+        product.setMerchant(dto.getMerchant());
+        product.setProductId(dto.getProductId());
+
+        return product;
+    }
 }

src/main/java/de/rwu/easydrop/service/mapping/package-info.java

@@ -1,6 +1,6 @@
 /**
  * Maps different formats of corresponding objects.
  *
- * TODO implement
+ * @since 0.2.0
  */
 package de.rwu.easydrop.service.mapping;