Add tests for IdentityLinkInterceptors and enhance SaveTaskCmds to ha… (flowable#4119)

* Add tests for IdentityLinkInterceptors and enhance SaveTaskCmds to handle assignee and owner changes

* Do not trigger IdentityLinkInterceptors when assignee or owner is removed

Author: roumn

modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/cmd/SaveTaskCmd.java

@@ -18,6 +18,7 @@
 import org.flowable.cmmn.engine.CmmnEngineConfiguration;
 import org.flowable.cmmn.engine.impl.task.TaskHelper;
 import org.flowable.cmmn.engine.impl.util.CommandContextUtil;
+import org.flowable.cmmn.engine.interceptor.CmmnIdentityLinkInterceptor;
 import org.flowable.common.engine.api.FlowableIllegalArgumentException;
 import org.flowable.common.engine.api.delegate.event.FlowableEngineEventType;
 import org.flowable.common.engine.impl.history.HistoryLevel;
@@ -76,6 +77,11 @@ public Void execute(CommandContext commandContext) {
 
             if (!StringUtils.equals(originalAssignee, task.getAssignee())) {
 
+                CmmnIdentityLinkInterceptor identityLinkInterceptor = cmmnEngineConfiguration.getIdentityLinkInterceptor();
+                if (identityLinkInterceptor != null && task.getAssignee() != null) {
+                    identityLinkInterceptor.handleAddAssigneeIdentityLinkToTask(task, task.getAssignee());
+                }
+
                 cmmnEngineConfiguration.getListenerNotificationHelper().executeTaskListeners(task, TaskListener.EVENTNAME_ASSIGNMENT);
 
                 if (CommandContextUtil.getEventDispatcher() != null && CommandContextUtil.getEventDispatcher().isEnabled()) {
@@ -84,6 +90,15 @@ public Void execute(CommandContext commandContext) {
                 }
 
             }
+
+            String originalOwner = originalTaskEntity.getOwner();
+
+            if (!StringUtils.equals(originalOwner, task.getOwner()) && task.getOwner() != null) {
+                CmmnIdentityLinkInterceptor identityLinkInterceptor = cmmnEngineConfiguration.getIdentityLinkInterceptor();
+                if (identityLinkInterceptor != null) {
+                    identityLinkInterceptor.handleAddOwnerIdentityLinkToTask(task, task.getOwner());
+                }
+            }
         }
 
         return null;

modules/flowable-cmmn-engine/src/main/java/org/flowable/cmmn/engine/impl/task/TaskHelper.java

@@ -166,12 +166,18 @@ public static void changeTaskOwner(TaskEntity taskEntity, String owner, CmmnEngi
     }
 
     protected static void addAssigneeIdentityLinks(TaskEntity taskEntity, CmmnEngineConfiguration cmmnEngineConfiguration) {
+        if (taskEntity.getAssignee() == null) {
+            return;
+        }
         if (cmmnEngineConfiguration.getIdentityLinkInterceptor() != null) {
             cmmnEngineConfiguration.getIdentityLinkInterceptor().handleAddAssigneeIdentityLinkToTask(taskEntity, taskEntity.getAssignee());
         }
     }
 
     protected static void addOwnerIdentityLink(TaskEntity taskEntity, CmmnEngineConfiguration cmmnEngineConfiguration) {
+        if (taskEntity.getOwner() == null) {
+            return;
+        }
         if (cmmnEngineConfiguration.getIdentityLinkInterceptor() != null) {
             cmmnEngineConfiguration.getIdentityLinkInterceptor().handleAddOwnerIdentityLinkToTask(taskEntity, taskEntity.getOwner());
         }