OPC UA adapter creation fails in case of nodes with StatusCode "good", but Null Value

[curichan]

Hi all,
while defining an OPC UA adapter I noticed that this fails when the node selection includes one or more nodes which report a StatusCode of "good", but have a Value of "Null". See an example here:

This prevents the creation of the adapter, although some of the nodes are actually fine. I think it'd be an improvement if the adapter could be created anyway as the problematic nodes may report "Null" only temporarily.
The relevant stacktrace is:
org.apache.streampipes.extensions.api.connect.exception.WorkerAdapterException: Could not guess schema for opc node: Cannot invoke "Object.getClass()" because "value" is null
at org.apache.streampipes.connect.management.management.GuessManagement.guessSchema(GuessManagement.java:77)
at org.apache.streampipes.rest.impl.connect.GuessResource.guessSchema(GuessResource.java:60)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.base/java.lang.reflect.Method.invoke(Unknown Source)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:52)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:134)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:177)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:176)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:81)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:478)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:400)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:81)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:261)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:248)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:244)
at org.glassfish.jersey.internal.Errors.process(Errors.java:292)
at org.glassfish.jersey.internal.Errors.process(Errors.java:274)
at org.glassfish.jersey.internal.Errors.process(Errors.java:244)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:265)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:240)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:697)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:394)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:346)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:357)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:311)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:205)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:223)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:53)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.springframework.security.web.FilterChainProxy.lambda$doFilterInternal$3(FilterChainProxy.java:231)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:365)
at org.springframework.security.web.access.intercept.AuthorizationFilter.doFilter(AuthorizationFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:126)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:120)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:131)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:85)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:179)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.apache.streampipes.rest.filter.TokenAuthenticationFilter.doFilterInternal(TokenAuthenticationFilter.java:86)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:107)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:93)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.web.filter.CorsFilter.doFilterInternal(CorsFilter.java:91)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:82)
at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:69)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:62)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.session.DisableEncodeUrlFilter.doFilterInternal(DisableEncodeUrlFilter.java:42)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:233)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:191)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:351)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.springframework.web.filter.FormContentFilter.doFilterInternal(FormContentFilter.java:93)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:185)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:158)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:177)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:97)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:542)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:119)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:92)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:78)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:357)
at org.apache.coyote.http11.Http11Processor.service(Http11Processor.java:400)
at org.apache.coyote.AbstractProcessorLight.process(AbstractProcessorLight.java:65)
at org.apache.coyote.AbstractProtocol$ConnectionHandler.process(AbstractProtocol.java:859)
at org.apache.tomcat.util.net.NioEndpoint$SocketProcessor.doRun(NioEndpoint.java:1734)
at org.apache.tomcat.util.net.SocketProcessorBase.run(SocketProcessorBase.java:52)
at org.apache.tomcat.util.threads.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1191)
at org.apache.tomcat.util.threads.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:659)
at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
at java.base/java.lang.Thread.run(Unknown Source)
Caused by: java.lang.Throwable: Could not guess schema for opc node: Cannot invoke "Object.getClass()" because "value" is null
at org.apache.streampipes.connect.iiot.adapters.opcua.utils.OpcUaUtil.getSchema(OpcUaUtil.java:125)
at org.apache.streampipes.connect.iiot.adapters.opcua.OpcUaAdapter.getSchema(OpcUaAdapter.java:272)
at org.apache.streampipes.connect.iiot.adapters.opcua.OpcUaAdapter.getSchema(OpcUaAdapter.java:62)
at org.apache.streampipes.extensions.management.connect.GuessManagement.guessSchema(GuessManagement.java:44)
at org.apache.streampipes.rest.extensions.connect.GuessResource.guessSchema(GuessResource.java:61)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.glassfish.jersey.server.model.internal.ResourceMethodInvocationHandlerFactory.lambda$static$0(ResourceMethodInvocationHandlerFactory.java:52)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher$1.run(AbstractJavaResourceMethodDispatcher.java:134)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.invoke(AbstractJavaResourceMethodDispatcher.java:177)
at org.glassfish.jersey.server.model.internal.JavaResourceMethodDispatcherProvider$ResponseOutInvoker.doDispatch(JavaResourceMethodDispatcherProvider.java:176)
at org.glassfish.jersey.server.model.internal.AbstractJavaResourceMethodDispatcher.dispatch(AbstractJavaResourceMethodDispatcher.java:81)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:478)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:400)
at org.glassfish.jersey.server.model.ResourceMethodInvoker.apply(ResourceMethodInvoker.java:81)
at org.glassfish.jersey.server.ServerRuntime$1.run(ServerRuntime.java:261)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:248)
at org.glassfish.jersey.internal.Errors$1.call(Errors.java:244)
at org.glassfish.jersey.internal.Errors.process(Errors.java:292)
at org.glassfish.jersey.internal.Errors.process(Errors.java:274)
at org.glassfish.jersey.internal.Errors.process(Errors.java:244)
at org.glassfish.jersey.process.internal.RequestScope.runInScope(RequestScope.java:265)
at org.glassfish.jersey.server.ServerRuntime.process(ServerRuntime.java:240)
at org.glassfish.jersey.server.ApplicationHandler.handle(ApplicationHandler.java:697)
at org.glassfish.jersey.servlet.WebComponent.serviceImpl(WebComponent.java:394)
at org.glassfish.jersey.servlet.WebComponent.service(WebComponent.java:346)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:357)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:311)
at org.glassfish.jersey.servlet.ServletContainer.service(ServletContainer.java:205)
at io.undertow.servlet.handlers.ServletHandler.handleRequest(ServletHandler.java:74)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:129)
at org.springframework.web.filter.RequestContextFilter.doFilterInternal(RequestContextFilter.java:100)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:67)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.security.web.FilterChainProxy.lambda$doFilterInternal$3(FilterChainProxy.java:231)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:365)
at org.springframework.security.web.access.intercept.AuthorizationFilter.doFilter(AuthorizationFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:126)
at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:120)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:131)
at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:85)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:100)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:179)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:63)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:107)
at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:93)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.header.HeaderWriterFilter.doHeadersAfter(HeaderWriterFilter.java:90)
at org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:75)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:82)
at org.springframework.security.web.context.SecurityContextHolderFilter.doFilter(SecurityContextHolderFilter.java:69)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:62)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.session.DisableEncodeUrlFilter.doFilterInternal(DisableEncodeUrlFilter.java:42)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:374)
at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:233)
at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:191)
at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:351)
at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:267)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:67)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at org.springframework.web.filter.CharacterEncodingFilter.doFilterInternal(CharacterEncodingFilter.java:201)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:116)
at io.undertow.servlet.core.ManagedFilter.doFilter(ManagedFilter.java:67)
at io.undertow.servlet.handlers.FilterHandler$FilterChainImpl.doFilter(FilterHandler.java:131)
at io.undertow.servlet.handlers.FilterHandler.handleRequest(FilterHandler.java:84)
at io.undertow.servlet.handlers.security.ServletSecurityRoleHandler.handleRequest(ServletSecurityRoleHandler.java:62)
at io.undertow.servlet.handlers.ServletChain$1.handleRequest(ServletChain.java:68)
at io.undertow.servlet.handlers.ServletDispatchingHandler.handleRequest(ServletDispatchingHandler.java:36)
at io.undertow.servlet.handlers.RedirectDirHandler.handleRequest(RedirectDirHandler.java:68)
at io.undertow.servlet.handlers.security.SSLInformationAssociationHandler.handleRequest(SSLInformationAssociationHandler.java:117)
at io.undertow.servlet.handlers.security.ServletAuthenticationCallHandler.handleRequest(ServletAuthenticationCallHandler.java:57)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.security.handlers.AbstractConfidentialityHandler.handleRequest(AbstractConfidentialityHandler.java:46)
at io.undertow.servlet.handlers.security.ServletConfidentialityConstraintHandler.handleRequest(ServletConfidentialityConstraintHandler.java:64)
at io.undertow.security.handlers.AuthenticationMechanismsHandler.handleRequest(AuthenticationMechanismsHandler.java:60)
at io.undertow.servlet.handlers.security.CachedAuthenticatedSessionHandler.handleRequest(CachedAuthenticatedSessionHandler.java:77)
at io.undertow.security.handlers.AbstractSecurityContextAssociationHandler.handleRequest(AbstractSecurityContextAssociationHandler.java:43)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.SendErrorPageHandler.handleRequest(SendErrorPageHandler.java:52)
at io.undertow.server.handlers.PredicateHandler.handleRequest(PredicateHandler.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.handleFirstRequest(ServletInitialHandler.java:276)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:135)
at io.undertow.servlet.handlers.ServletInitialHandler$2.call(ServletInitialHandler.java:132)
at io.undertow.servlet.core.ServletRequestContextThreadSetupAction$1.call(ServletRequestContextThreadSetupAction.java:48)
at io.undertow.servlet.core.ContextClassLoaderSetupAction$1.call(ContextClassLoaderSetupAction.java:43)
at io.undertow.servlet.handlers.ServletInitialHandler.dispatchRequest(ServletInitialHandler.java:256)
at io.undertow.servlet.handlers.ServletInitialHandler$1.handleRequest(ServletInitialHandler.java:101)
at io.undertow.server.Connectors.executeRootHandler(Connectors.java:393)
at io.undertow.server.HttpServerExchange$1.run(HttpServerExchange.java:859)
at org.jboss.threads.ContextHandler$1.runWith(ContextHandler.java:18)
at org.jboss.threads.EnhancedQueueExecutor$Task.run(EnhancedQueueExecutor.java:2513)
at org.jboss.threads.EnhancedQueueExecutor$ThreadBody.run(EnhancedQueueExecutor.java:1538)
at org.xnio.XnioWorker$WorkerThreadFactory$1$1.run(XnioWorker.java:1282)
at java.lang.Thread.run(Unknown Source)
Caused by: java.lang.Throwable: Cannot invoke "Object.getClass()" because "value" is null
at org.apache.streampipes.connect.iiot.adapters.opcua.utils.OpcUaUtil.makeEventPreview(OpcUaUtil.java:149)
at org.apache.streampipes.connect.iiot.adapters.opcua.utils.OpcUaUtil.getSchema(OpcUaUtil.java:121)
... 108 more

[tenthe]

Hello @curichan,
thank you for the report.

Do I understand it correctly. In your example all metadata is present but the actual value is null right?
If this is the case, I would suggest that we define a complete strategy for this problem, as this can happen not only during the creation of the adapter, but also during runtime. So the question is what is the expected behavior.

In general, we don't allow incorrect values within the event because then downstream algorithms have to deal with all these cases. We could either remove the value from the event or add a default value.

What do the others think?

Cheers.
Philipp

[curichan]

Hi @tenthe,
yes, the metadata is as shown in the screenshot, simply the value is null.
My gut feeling would be that removing the value from the event is the way forward, as it simply is not available. Replacing it with a default value could cause confusion with steps down the line as it will be virtually impossible to use a general default value that is not used as a "meaningful" value in some context by someone... Unless there was some functionality that would allow users to choose their own default for missing values at creation time of the adapter?
Cheers,
Christian.

[tenthe]

I am also not in favor of introducing a default value.
I see two options:

• Option 1: Remove the property from the event schema
  • Disadvantage: We also need to check that the values are not null at runtime
  • Advantage: We know (at connection time) that all values are present
• Option 2: Remove the property during runtime.
  • Disadvantage: The downstream algorithms have to handle this case. The user might get errors in pipeline elements due to missing values in the data source.
  • Advantage: There are no restrictions for the user.