It there a complete example of how to create CustomCollectionDatasource

Is there a good example of how to create CustomCollectionDatasource.
I have looked at the 4.5.3.1.3. Custom Implementation Classes and created my own implementation from this example


class VbPartticipantDs extends CustomCollectionDatasource{

        @Override
        protected Collection<VbhParticipant> getEntities(Map params) {
            LoadContext loadContext = LoadContext.create(VbhParticipant.class)
                    .setQuery(LoadContext.createQuery("select vp from titanium$VbhParticipant vp"))
                    .setView("vbhParticipant-browser");
            return dataManager.loadList(loadContext);
        }
    }

I got this exception


java.lang.NullPointerException
	at com.haulmont.cuba.core.global.MetadataTools.resolveMetaPropertyPath(MetadataTools.java:657)
	at com.haulmont.cuba.core.sys.SecurityImpl.isEntityAttrReadPermitted(SecurityImpl.java:104)
	at com.haulmont.cuba.web.gui.components.WebAbstractTable.getPropertyColumns(WebAbstractTable.java:1034)
	at com.haulmont.cuba.web.gui.components.WebAbstractTable.setDatasource(WebAbstractTable.java:819)
	at com.dirdalit.titanium.web.test.TestEdit.onButtonClick(TestEdit.java:45)
	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.haulmont.cuba.gui.xml.DeclarativeAction.actionPerform(DeclarativeAction.java:84)
	at com.haulmont.cuba.web.gui.components.WebButton.performAction(WebButton.java:44)
	at com.haulmont.cuba.web.gui.components.WebButton.lambda$new$61446b05$1(WebButton.java:36)
	at sun.reflect.GeneratedMethodAccessor187.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.vaadin.event.ListenerMethod.receiveEvent(ListenerMethod.java:508)
	at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:198)
	at com.vaadin.event.EventRouter.fireEvent(EventRouter.java:161)
	at com.vaadin.server.AbstractClientConnector.fireEvent(AbstractClientConnector.java:1030)
	at com.vaadin.ui.Button.fireClick(Button.java:377)
	at com.haulmont.cuba.web.toolkit.ui.CubaButton.fireClick(CubaButton.java:54)
	at com.vaadin.ui.Button$1.click(Button.java:54)
	at sun.reflect.GeneratedMethodAccessor186.invoke(Unknown Source)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:498)
	at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:158)
	at com.vaadin.server.ServerRpcManager.applyInvocation(ServerRpcManager.java:118)
	at com.vaadin.server.communication.ServerRpcHandler.handleInvocations(ServerRpcHandler.java:414)
	at com.vaadin.server.communication.ServerRpcHandler.handleRpc(ServerRpcHandler.java:274)
	at com.vaadin.server.communication.UidlRequestHandler.synchronizedHandleRequest(UidlRequestHandler.java:79)
	at com.haulmont.cuba.web.sys.CubaVaadinServletService$CubaUidlRequestHandler.lambda$synchronizedHandleRequest$107(CubaVaadinServletService.java:314)
	at com.haulmont.cuba.web.sys.CubaVaadinServletService.withUserSession(CubaVaadinServletService.java:196)
	at com.haulmont.cuba.web.sys.CubaVaadinServletService$CubaUidlRequestHandler.synchronizedHandleRequest(CubaVaadinServletService.java:314)
	at com.vaadin.server.SynchronizedRequestHandler.handleRequest(SynchronizedRequestHandler.java:41)
	at com.vaadin.server.VaadinService.handleRequest(VaadinService.java:1409)
	at com.vaadin.server.VaadinServlet.service(VaadinServlet.java:369)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.serviceAppRequest(CubaApplicationServlet.java:278)
	at com.haulmont.cuba.web.sys.CubaApplicationServlet.service(CubaApplicationServlet.java:187)
	at javax.servlet.http.HttpServlet.service(HttpServlet.java:729)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:292)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at com.haulmont.cuba.web.sys.CubaHttpFilter.handleNotFiltered(CubaHttpFilter.java:108)
	at com.haulmont.cuba.web.sys.CubaHttpFilter.doFilter(CubaHttpFilter.java:95)
	at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:240)
	at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:207)
	at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:212)
	at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:106)
	at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
	at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:141)
	at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:79)
	at org.apache.catalina.valves.AbstractAccessLogValve.invoke(AbstractAccessLogValve.java:616)
	at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:88)
	at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:528)
	at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1099)
	at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:672)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1520)
	at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.run(NioEndpoint.java:1476)
	at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
	at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
	at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
	at java.lang.Thread.run(Thread.java:745)

1 Like

Hi,

in fact, there is. Aleksey created one a few weeks ago: https://github.com/aleksey-stukalov/custom-datasource

Bye,
Mario

I was also looking for a good example of Customer Datasource. The link takes to an example that is nice but I was looking for something similar to the question here…

Your custom datasource should work, just make sure you have specified also the class of entity in your XML descriptor:

<dsContext>
    <collectionDatasource id="myDs"
                          class="com.company.sample.entity.MyEntity"
                          datasourceClass="com.company.sample.web.screens.MyDatasource">
    </collectionDatasource>
</dsContext>