I'm currently developing an application with Vaadin Flow (v11.0.0) and Spring Boot (v2.0.4) using the MVP pattern. The application works fine, as long as it's only open in a single tab. When reloading the whole page is refreshed, which is totally fine. Also opening it in a second tab or window (doesn't matter if incognito or not) works fine. But when I click something in one window and then in the other one the following error occures:
java.lang.IllegalStateException: Cannot access state in VaadinSession or UI without locking the session.
at com.vaadin.flow.server.VaadinSession.checkHasLock(VaadinSession.java:515) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.server.VaadinSession.checkHasLock(VaadinSession.java:529) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.StateTree.checkHasLock(StateTree.java:390) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.StateTree.markAsDirty(StateTree.java:258) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.StateNode.markAsDirty(StateNode.java:326) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.nodefeature.NodeValue.markAsDirty(NodeValue.java:85) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.nodefeature.NodeValue.setValue(NodeValue.java:78) ~[flow-server-1.0.5.jar:na]
at com.vaadin.flow.internal.nodefeature.TextNodeMap.setText(TextNodeMap.java:52) ~[flow-server-1.0.5.jar:na]
I only have a single view (and therefore also presenter) which I annotate like that:
@Route(value = LogAnalysis.route)
@PageTitle(LogAnalysis.name)
class LogAnalysisView(val presenter: LogAnalysis.ViewPresenter) : VerticalLayout(), LogAnalysis.View, BeforeEnterObserver { ... }
@Component
@UIScope
@VaadinSessionScope
class LogAnalysisPresenter(val service: LogAnalysis.Service) : LogAnalysis.ServicePresenter, LogAnalysis.ViewPresenter { ... }
I managed to solve the issue by adding the @UIScope annotation to the Service (model) as well.
I assumed that the service can be a singleton, as it is only fetching and preparing data from the database, but the service holds a reference to the presenter which gets overwritten every time a new Session is created.