OO-2840: allow to delete list of items with an already deleted item within

src/main/java/org/olat/modules/qpool/manager/QuestionItemDAO.java

@@ -36,6 +36,8 @@ import org.olat.basesecurity.SecurityGroupMembershipImpl;
 import org.olat.core.commons.persistence.DB;
 import org.olat.core.commons.services.mark.impl.MarkImpl;
 import org.olat.core.id.Identity;
+import org.olat.core.logging.OLog;
+import org.olat.core.logging.Tracing;
 import org.olat.core.util.StringHelper;
 import org.olat.group.BusinessGroup;
 import org.olat.modules.qpool.QuestionItem;
@@ -60,6 +62,8 @@ import org.springframework.stereotype.Service;
 @Service("questionDao")
 public class QuestionItemDAO {
 	
+	private static final OLog log = Tracing.createLoggerFor(QuestionItemDAO.class);
+	
 	@Autowired
 	private DB dbInstance;
 	@Autowired
@@ -222,14 +226,42 @@ public class QuestionItemDAO {
 		return query.getResultList();
 	}
 	
-	public void delete(List<QuestionItemShort> items) {
+	public void delete(List<? extends QuestionItemShort> items) {
 		EntityManager em = dbInstance.getCurrentEntityManager();
 		for(QuestionItemShort item:items) {
-			QuestionItem refItem = em.getReference(QuestionItemImpl.class, item.getKey());
-			em.remove(refItem);
+			QuestionItem refItem = loadLazyReferenceId(item.getKey());
+			if(refItem != null) {
+				em.remove(refItem);
+			}
 		}
 	}
 	
+	/**
+	 * The method only load the question item and doesn't fetch
+	 * anything.
+	 * 
+	 * @param key The primary key of the item
+	 * @return The question item or null if not found
+	 */
+	private QuestionItem loadLazyReferenceId(Long key) {
+		StringBuilder sb = new StringBuilder();
+		sb.append("select item from questionitem item")
+		  .append(" where item.key=:key");
+		List<QuestionItem> items = dbInstance.getCurrentEntityManager()
+				.createQuery(sb.toString(), QuestionItem.class)
+				.setParameter("key", key)
+				.getResultList();
+		return items == null || items.isEmpty() ? null : items.get(0);
+	}
+	
+	/**
+	 * The method loads the question item and fetch
+	 * the taxonomy level, license, item type and
+	 * educational context.
+	 * 
+	 * @param key The primary key of the item
+	 * @return The question item or null if not found
+	 */
 	public QuestionItemImpl loadById(Long key) {
 		StringBuilder sb = new StringBuilder();
 		sb.append("select item from questionitem item")

src/test/java/org/olat/modules/qpool/manager/QuestionDAOTest.java

@@ -20,6 +20,7 @@
 package org.olat.modules.qpool.manager;
 
 import java.math.BigDecimal;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
 import java.util.Locale;
@@ -451,4 +452,41 @@ public class QuestionDAOTest extends OlatTestCase {
 		Assert.assertEquals(1, count);
 		dbInstance.commit();//make sure that changes are committed
 	}
+	
+	@Test
+	public void deleteQuestion() {
+		QItemType fibType = qItemTypeDao.loadByType(QuestionType.FIB.name());
+		QuestionItem item = questionDao.createAndPersist(null, "To delete 1", QTIConstants.QTI_12_FORMAT, Locale.ENGLISH.getLanguage(), null, null, null, fibType);
+		dbInstance.commitAndCloseSession();
+		
+		List<QuestionItem> itemsToDelete = Collections.singletonList(item);
+		questionDao.delete(itemsToDelete);
+		dbInstance.commitAndCloseSession();
+		
+		QuestionItem deletedItem = questionDao.loadById(item.getKey());
+		Assert.assertNull(deletedItem);
+	}
+	
+	@Test
+	public void deleteQuestion_alreadyDeletedQuestions() {
+		QItemType fibType = qItemTypeDao.loadByType(QuestionType.FIB.name());
+		QuestionItem item1 = questionDao.createAndPersist(null, "To delete 1", QTIConstants.QTI_12_FORMAT, Locale.ENGLISH.getLanguage(), null, null, null, fibType);
+		QuestionItem item2 = questionDao.createAndPersist(null, "To delete 2", QTIConstants.QTI_12_FORMAT, Locale.ENGLISH.getLanguage(), null, null, null, fibType);
+		dbInstance.commitAndCloseSession();
+		
+		// delete item 1
+		questionDao.delete(Collections.singletonList(item1));
+		dbInstance.commitAndCloseSession();
+		
+		List<QuestionItem> itemsToDelete = new ArrayList<>();
+		itemsToDelete.add(item1);
+		itemsToDelete.add(item2);
+		questionDao.delete(itemsToDelete);
+		dbInstance.commitAndCloseSession();
+		
+		QuestionItem deletedItem1 = questionDao.loadById(item1.getKey());
+		Assert.assertNull(deletedItem1);
+		QuestionItem deletedItem2 = questionDao.loadById(item2.getKey());
+		Assert.assertNull(deletedItem2);
+	}
 }
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