TSK-1355: Adjust all single() methods to use mybatis selectOne

history/taskana-simplehistory-provider/src/main/java/pro/taskana/simplehistory/impl/ClassificationHistoryQueryImpl.java

@@ -493,14 +493,10 @@ public class ClassificationHistoryQueryImpl implements ClassificationHistoryQuer
     LOGGER.debug("entry to single(), this = {}", this);
     ClassificationHistoryEvent result = null;
     try {
+
       taskanaHistoryEngine.openConnection();
-      List<ClassificationHistoryEvent> results =
+      result = taskanaHistoryEngine.getSqlSession().selectOne(LINK_TO_MAPPER, this);
-          taskanaHistoryEngine.getSqlSession().selectList(LINK_TO_MAPPER, this);
+
-      if (results.isEmpty()) {
-        return result;
-      } else {
-        result = results.get(0);
-      }
       return result;
     } catch (SQLException e) {
       LOGGER.error(SQL_EXCEPTION_MESSAGE, e.getCause());

history/taskana-simplehistory-provider/src/main/java/pro/taskana/simplehistory/impl/TaskHistoryQueryImpl.java

@@ -702,14 +702,10 @@ public class TaskHistoryQueryImpl implements TaskHistoryQuery {
     TaskHistoryEvent result = null;
     try {
       taskanaHistoryEngine.openConnection();
-      List<TaskHistoryEvent> results =
+      result = taskanaHistoryEngine.getSqlSession().selectOne(LINK_TO_MAPPER, this);
-          taskanaHistoryEngine.getSqlSession().selectList(LINK_TO_MAPPER, this);
+
-      if (results.isEmpty()) {
-        return result;
-      } else {
-        result = results.get(0);
-      }
       return result;
+
     } catch (SQLException e) {
       LOGGER.error(SQL_EXCEPTION_MESSAGE, e.getCause());
       return result;

history/taskana-simplehistory-provider/src/main/java/pro/taskana/simplehistory/impl/WorkbasketHistoryQueryImpl.java

@@ -546,13 +546,8 @@ public class WorkbasketHistoryQueryImpl implements WorkbasketHistoryQuery {
     WorkbasketHistoryEvent result = null;
     try {
       taskanaHistoryEngine.openConnection();
-      List<WorkbasketHistoryEvent> results =
+      result = taskanaHistoryEngine.getSqlSession().selectOne(LINK_TO_MAPPER, this);
-          taskanaHistoryEngine.getSqlSession().selectList(LINK_TO_MAPPER, this);
+
-      if (results.isEmpty()) {
-        return result;
-      } else {
-        result = results.get(0);
-      }
       return result;
     } catch (SQLException e) {
       LOGGER.error(SQL_EXCEPTION_MESSAGE, e.getCause());

history/taskana-simplehistory-provider/src/test/java/acceptance/query/QueryClassificationHistoryAccTest.java

@@ -1,11 +1,13 @@
 package acceptance.query;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import acceptance.AbstractAccTest;
 import java.time.Instant;
 import java.util.Collections;
 import java.util.List;
+import org.apache.ibatis.exceptions.TooManyResultsException;
 import org.junit.jupiter.api.Test;
 
 import pro.taskana.classification.api.ClassificationCustomField;
@@ -96,17 +98,31 @@ class QueryClassificationHistoryAccTest extends AbstractAccTest {
   @Test
   void should_ReturnSingleHistoryEvent_When_UsingSingleMethod() {
     ClassificationHistoryEvent single =
-        historyService.createClassificationHistoryQuery().userIdIn("peter").single();
+        historyService
+            .createClassificationHistoryQuery()
+            .userIdIn("peter")
+            .classificationIdIn("CLI:000000000000000000000000000000000001")
+            .single();
     assertThat(single.getEventType()).isEqualTo(ClassificationHistoryEventType.CREATED.getName());
 
     single =
         historyService
             .createClassificationHistoryQuery()
             .eventTypeIn(ClassificationHistoryEventType.CREATED.getName(), "xy")
+            .classificationIdIn("CLI:000000000000000000000000000000000001")
             .single();
     assertThat(single.getUserId()).isEqualTo("peter");
   }
 
+  @Test
+  void should_ThrowException_When_SingleMethodRetrievesMoreThanOneEventFromDatabase() {
+
+    ClassificationHistoryQuery query =
+        getHistoryService().createClassificationHistoryQuery().userIdIn("peter");
+
+    assertThatThrownBy(() -> query.single()).isInstanceOf(TooManyResultsException.class);
+  }
+
   @Test
   void should_ReturnCountOfEvents_When_UsingCountMethod() {
     long count = historyService.createClassificationHistoryQuery().userIdIn("peter").count();

history/taskana-simplehistory-provider/src/test/java/acceptance/query/QueryTaskHistoryAccTest.java

@@ -2,11 +2,13 @@ package acceptance.query;
 
 import static java.lang.String.CASE_INSENSITIVE_ORDER;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import acceptance.AbstractAccTest;
 import java.time.Instant;
 import java.util.Collections;
 import java.util.List;
+import org.apache.ibatis.exceptions.TooManyResultsException;
 import org.junit.jupiter.api.Test;
 
 import pro.taskana.common.api.BaseQuery.SortDirection;
@@ -86,17 +88,31 @@ class QueryTaskHistoryAccTest extends AbstractAccTest {
   @Test
   void should_ReturnSingleHistoryEvent_When_UsingSingleMethod() {
     TaskHistoryEvent single =
-        getHistoryService().createTaskHistoryQuery().userIdIn("peter").single();
+        getHistoryService()
+            .createTaskHistoryQuery()
+            .userIdIn("peter")
+            .taskIdIn("TKI:000000000000000000000000000000000036")
+            .single();
+
     assertThat(single.getEventType()).isEqualTo(TaskHistoryEventType.CREATED.getName());
 
     single =
         getHistoryService()
             .createTaskHistoryQuery()
             .eventTypeIn(TaskHistoryEventType.CREATED.getName(), "xy")
+            .idIn("THI:000000000000000000000000000000000003")
             .single();
     assertThat(single.getUserId()).isEqualTo("peter");
   }
 
+  @Test
+  void should_ThrowException_When_SingleMethodRetrievesMoreThanOneEventFromDatabase() {
+
+    TaskHistoryQuery query = getHistoryService().createTaskHistoryQuery().userIdIn("peter");
+
+    assertThatThrownBy(() -> query.single()).isInstanceOf(TooManyResultsException.class);
+  }
+
   @Test
   void should_ReturnCountOfEvents_When_UsingCountMethod() {
     long count = getHistoryService().createTaskHistoryQuery().userIdIn("peter").count();

history/taskana-simplehistory-provider/src/test/java/acceptance/query/QueryWorkbasketHistoryAccTest.java

@@ -1,11 +1,13 @@
 package acceptance.query;
 
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.assertThatThrownBy;
 
 import acceptance.AbstractAccTest;
 import java.time.Instant;
 import java.util.Collections;
 import java.util.List;
+import org.apache.ibatis.exceptions.TooManyResultsException;
 import org.junit.jupiter.api.Test;
 
 import pro.taskana.common.api.BaseQuery.SortDirection;
@@ -96,17 +98,31 @@ class QueryWorkbasketHistoryAccTest extends AbstractAccTest {
   @Test
   void should_ReturnSingleHistoryEvent_When_UsingSingleMethod() {
     WorkbasketHistoryEvent single =
-        historyService.createWorkbasketHistoryQuery().userIdIn("peter").single();
+        historyService
+            .createWorkbasketHistoryQuery()
+            .userIdIn("peter")
+            .idIn("WHI:000000000000000000000000000000000000")
+            .single();
     assertThat(single.getEventType()).isEqualTo(WorkbasketHistoryEventType.CREATED.getName());
 
     single =
         historyService
             .createWorkbasketHistoryQuery()
             .eventTypeIn(WorkbasketHistoryEventType.CREATED.getName(), "xy")
+            .idIn("WHI:000000000000000000000000000000000000")
             .single();
     assertThat(single.getUserId()).isEqualTo("peter");
   }
 
+  @Test
+  void should_ThrowException_When_SingleMethodRetrievesMoreThanOneEventFromDatabase() {
+
+    WorkbasketHistoryQuery query =
+        getHistoryService().createWorkbasketHistoryQuery().userIdIn("peter");
+
+    assertThatThrownBy(() -> query.single()).isInstanceOf(TooManyResultsException.class);
+  }
+
   @Test
   void should_ReturnCountOfEvents_When_UsingCountMethod() {
     long count = historyService.createWorkbasketHistoryQuery().userIdIn("peter").count();