When editing an updating Grid, I get exception..

I’ve been trying to figure out, what is wrong in my code. When I go to edit some of the data in grid, I get this exception…

10:03:03.833 [qtp279680875-909] ERROR c.vaadin.server.DefaultErrorHandler - 
java.lang.IllegalStateException: Duplicate key Person(firstName=matti222, lastName=meikalainen22, sotu=111111)
        at java.util.stream.Collectors.lambda$throwingMerger$0(Collectors.java:133)
        at java.util.HashMap.merge(HashMap.java:1245)
        at java.util.stream.Collectors.lambda$toMap$58(Collectors.java:1320)
        at java.util.stream.ReduceOps$3ReducingSink.accept(ReduceOps.java:169)
        at java.util.stream.ReferencePipeline$3$1.accept(ReferencePipeline.java:193)
        at java.util.HashMap$KeySpliterator.forEachRemaining(HashMap.java:1540)
        at java.util.stream.AbstractPipeline.copyInto(AbstractPipeline.java:481)
        at java.util.stream.AbstractPipeline.wrapAndCopyInto(AbstractPipeline.java:471)
        at java.util.stream.ReduceOps$ReduceOp.evaluateSequential(ReduceOps.java:708)
        at java.util.stream.AbstractPipeline.evaluate(AbstractPipeline.java:234)
        at java.util.stream.ReferencePipeline.collect(ReferencePipeline.java:499)
        at com.vaadin.data.provider.DataCommunicator$ActiveDataHandler.getActiveData(DataCommunicator.java:165)
        at com.vaadin.data.provider.DataCommunicator.refresh(DataCommunicator.java:521)
        at com.vaadin.ui.AbstractListing$AbstractListingExtension.refresh(AbstractListing.java:122)
        at com.vaadin.ui.components.grid.EditorImpl.save(EditorImpl.java:250)
        at com.vaadin.ui.components.grid.EditorImpl$1.save(EditorImpl.java:133)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:155)
        at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:116)
        at com.vaadin.server.communication.ServerRpcHandler.handleInvocation(ServerRpcHandler.java:445)
        at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:410)
        at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:274)
        at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:90)
        at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
        at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1577)
        at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:381)
        at javax.servlet.http.HttpServlet.service(HttpServlet.java:790)
        at org.eclipse.jetty.servlet.ServletHolder.handle(ServletHolder.java:812)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1669)
        at org.eclipse.jetty.websocket.server.WebSocketUpgradeFilter.doFilter(WebSocketUpgradeFilter.java:224)
        at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1652)
        at org.eclipse.jetty.servlet.ServletHandler.doHandle(ServletHandler.java:585)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:143)
        at org.eclipse.jetty.security.SecurityHandler.handle(SecurityHandler.java:577)
        at org.eclipse.jetty.server.session.SessionHandler.doHandle(SessionHandler.java:223)
        at org.eclipse.jetty.server.handler.ContextHandler.doHandle(ContextHandler.java:1127)
        at org.eclipse.jetty.servlet.ServletHandler.doScope(ServletHandler.java:515)
        at org.eclipse.jetty.server.session.SessionHandler.doScope(SessionHandler.java:185)
        at org.eclipse.jetty.server.handler.ContextHandler.doScope(ContextHandler.java:1061)
        at org.eclipse.jetty.server.handler.ScopedHandler.handle(ScopedHandler.java:141)
        at org.eclipse.jetty.server.handler.ContextHandlerCollection.handle(ContextHandlerCollection.java:215)
        at org.eclipse.jetty.server.handler.HandlerWrapper.handle(HandlerWrapper.java:97)
        at org.eclipse.jetty.server.Server.handle(Server.java:499)
        at org.eclipse.jetty.server.HttpChannel.handle(HttpChannel.java:311)
        at org.eclipse.jetty.server.HttpConnection.onFillable(HttpConnection.java:257)
        at org.eclipse.jetty.io.AbstractConnection$2.run(AbstractConnection.java:544)
        at org.eclipse.jetty.util.thread.QueuedThreadPool.runJob(QueuedThreadPool.java:635)
        at org.eclipse.jetty.util.thread.QueuedThreadPool$3.run(QueuedThreadPool.java:555)
        at java.lang.Thread.run(Thread.java:745)

And here is the code I’m using:

data class Person(var firstName: String, var lastName: String, var sotu: String)


/**
 * Person View
 */


@AutoView("")
class TestView: VerticalLayout(), View {


    private lateinit  var personGrid: Grid<Person>
    private lateinit  var firstNameFilter: TextField
    var persons = listOf<Person>(Person("matti", "meikalainen", "111111"), Person("teppo", "testaajaa", "2222222"))

    companion object {
        fun navigateTo() = navigateToView<WelcomeView>()
    }

    init {

        var personsListProvider = ListDataProvider<Person>(persons).withConfigurableFilter()


        isMargin = false
        label("Vaadin On Kotlin testview") {
            w = fillParent
            addStyleNames(ValoTheme.LABEL_H1, ValoTheme.LABEL_COLORED)
        }


        personGrid = grid(Person::class, "List of Persons", dataProvider = personsListProvider) {
            expandRatio = 1f;
            setSizeFull()

            val binder: Binder<Person> = getEditor().getBinder()

            column(Person::firstName) {
                caption="firstname"
                setEditorComponent(TextField("firstname"), Person::firstName.setter)
               isEditable = true
                isHidden = false
            }




            column(Person::lastName) {
                setEditorComponent(TextField("lastname"), Person::lastName.setter)
                isEditable = true
            }

            column(Person::sotu) {
                setEditorComponent(TextField("sotu"), Person::sotu.setter)
                isEditable = true

            }

            editor.addCancelListener( { event -> Notification.show("Editing Cancelled...")
            } )
            editor.addSaveListener({ event ->
                Notification.show("Saving ${event.bean.firstName} - ${event.bean.lastName} - ${event.bean.sotu} -...")
                binder.writeBean(event.bean)

                personsListProvider.refreshAll()

                // just for debugging to see what's in the provider now..
                personsListProvider.getAll().forEach(
                        {
                            println("${it.firstName} - ${it.lastName} - ${it.sotu}")
                        }
                )

                refresh()

            })

            editor.setSaveCaption("Tallenna")
            editor.setCancelCaption("Peruuta")

            editor.setEnabled(true)

            addColumn({ "Show" }, ButtonRenderer<Person>({ event -> personGrid.refresh() }))
            addColumn({ "Edit" }, ButtonRenderer<Person>({ event -> null }))
            addColumn({ "Delete" }, ButtonRenderer<Person>({ event -> null }))

            // automatically create filters, based on the types of values present in particular columns.
            appendHeaderRow().generateFilterComponents(this, Person::class)


        }

        personGrid.addItemClickListener({ event -> Notification.show("Value: " + event.getItem()) })

    }


    override fun enter(event: ViewChangeListener.ViewChangeEvent?) {
        personGrid.dataProvider.refreshAll()
    }

}

Even if I leave the whole ListDataProvider out of it, I still get the same duplicate key error. So I’m starting to wonder, is this a bug in Vaadin, or am I just doing something wrong? Is the problem with ListDataProvider, or with the Binder? I’m just not getting it how to use this properly through the docs…

[DALDEI]

I have hit similar but not identical symptoms – may or may not be the same. My case, the grid started behaving very strangely but didn’t always crash – I debuged/resolved it by following the hints in the docs about unique ID’s. The DataProvider getId() uses Object.equals() in some places - basically the same rules for ‘identity’ for Java collections. Depending on the specifics of the object – in kotlin - variants on interface/class/data class, @JvmField, @JvmStatic , extension properties etc can lead to 2 objects being ‘the same’ even if they are not (or visa-versa). I solved it with a derived DataProvider with a custom getId()

NOTE: the object in question came from vok-db , where “id” is a special property that’s required for data binding and DB access. For a while I was confused that this was what was being used by DataProvider.
Note: I’ve found the ‘safest’ classes to use for Grid are ‘pure’ ‘data class’ kotlin classes with nothihng fancy. Vaadin does a ‘very good’ job at discovering properties - often ‘too good’ for kotlin - finding functions or extension properties not intended for UI puproses. I havent yet found a clean way to ignore these in general to the point that I often dynamically generate classes at runtime just to put in a grid in a reproducible/reliably way with consistent naming.

[skoude]

Here’s the link to the bug: https://github.com/vaadin/framework/issues/9678