Create placeholders for parent categories that have not been imported

when a child category is imported, and update them when that category is
imported.

ccm-core/src/main/java/org/libreccm/categorization/CategoryIdResolver.java

@@ -23,7 +23,9 @@ import com.fasterxml.jackson.annotation.ObjectIdResolver;
 import org.libreccm.cdi.utils.CdiUtil;
 
 import javax.enterprise.context.RequestScoped;
+
 import java.io.Serializable;
+import java.util.Optional;
 
 /**
  * Used by the {@link CategorizationImExporter} to resolve categories based on
@@ -49,18 +51,41 @@ public class CategoryIdResolver implements Serializable, ObjectIdResolver {
 
     @Override
     public Object resolveId(final ObjectIdGenerator.IdKey id) {
-        return CdiUtil
+        final Optional<Category> result = CdiUtil
             .createCdiUtil()
             .findBean(CategoryRepository.class)
-            .findByUuid(id.key.toString())
-            .orElseThrow(
-                () -> new IllegalArgumentException(
-                    String.format(
-                        "No Category with UUID %s in the database.",
-                        id.key.toString()
-                    )
+            .findByUuid(id.key.toString());
+        if (result.isPresent()) {
+            return result.get();
+        } else {
+            final Category category = new Category();
+            category.setUuid(id.key.toString());
+            category.setUniqueId(id.key.toString());
+            category.setName(
+                String.format(
+                    "placeholder-%s",
+                    id.key.toString()
                 )
             );
+            CdiUtil
+                .createCdiUtil()
+                .findBean(CategoryRepository.class)
+                .save(category);
+            return category;
+        }
+//
+//        return CdiUtil
+//            .createCdiUtil()
+//            .findBean(CategoryRepository.class)
+//            .findByUuid(id.key.toString())
+//            .orElseThrow(
+//                () -> new IllegalArgumentException(
+//                    String.format(
+//                        "No Category with UUID %s in the database.",
+//                        id.key.toString()
+//                    )
+//                )
+//            );
     }
 
     @Override

ccm-core/src/main/java/org/libreccm/categorization/CategoryImExporter.java

@@ -24,12 +24,15 @@ import org.libreccm.imexport.Processes;
 
 import java.util.HashSet;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.Set;
 
 import javax.enterprise.context.RequestScoped;
 import javax.inject.Inject;
 import javax.transaction.Transactional;
 
+import static com.ctc.wstx.shaded.msv_core.datatype.xsd.NumberType.save;
+
 /**
  * Exporter/Importer for {@link Category} entities.
  * 
@@ -58,7 +61,29 @@ public class CategoryImExporter extends AbstractEntityImExporter<Category> {
     @Override
     @Transactional(Transactional.TxType.REQUIRED)
     protected void saveImportedEntity(final Category entity) {
-        categoryRepository.save(entity);
+        final Optional<Category> result = categoryRepository.findByUuid(
+            entity.getUuid()
+        );
+        
+        final Category category;
+        if (result.isPresent()) {
+           category = result.get();
+           category.setAbstractCategory(entity.isAbstractCategory());
+           category.setCategoryOrder(entity.getCategoryOrder());
+           category.setDescription(entity.getDescription());
+           category.setDisplayName(entity.getDisplayName());
+           category.setEnabled(entity.isEnabled());
+           category.setName(entity.getName());
+           category.setObjects(entity.getObjects());
+           category.setParentCategory(entity.getParentCategory());
+           category.setSubCategories(entity.getSubCategories());
+           category.setTitle(entity.getTitle());
+           category.setUniqueId(entity.getUniqueId());
+           category.setVisible(entity.isVisible()); 
+        } else {
+            category = entity;
+        }
+        categoryRepository.save(category);
     }
 
     @Override