generating xtext artifacts errors - eclipse

Question

I am trying to create a new DSL grammar, so I have developed an ecore model and imported to the xtext grammar file, the xtext file has generated and without errors. later on I have faced mainly 3 errors:
a noisy pop up error "An error has occurred. See error log for more details. java.lang.NullPointerException"
when I try to generate the xtext artifacts, it was terminated after a lot of errors, and the errors in below
++++++++++++++++++++++++++++++++++++++++++++++++++++++
0 [main] INFO lipse.emf.mwe.utils.StandaloneSetup - Registering platform uri 'C:\Users\MAISA\Desktop\eclipse-epsilon-1.2-win32-x86_64\workspace'
141 [main] ERROR mf.mwe2.launch.runtime.Mwe2Launcher - Problems instantiating module org.xtext.example.mydsl.WSNDSL:
java.lang.reflect.InvocationTargetException
java.lang.RuntimeException: Problems instantiating module org.xtext.example.mydsl.WSNDSL:
java.lang.reflect.InvocationTargetException
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Runner.run(Mwe2Runner.java:95)
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Runner.run(Mwe2Runner.java:62)
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Runner.run(Mwe2Runner.java:52)
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher.run(Mwe2Launcher.java:78)
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Launcher.main(Mwe2Launcher.java:36)
Caused by: org.eclipse.emf.common.util.WrappedException: java.lang.reflect.InvocationTargetException
at org.eclipse.emf.mwe2.language.factory.SettingProviderImpl$1$1.setValue(SettingProviderImpl.java:56)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.internalApplyAssignments
(Mwe2ExecutionEngine.java:143)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.inCase(Mwe2ExecutionEngine.java:114)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:296)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.internalSwitch(Mwe2ExecutionEngine.java:66)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.internalApplyAssignments
(Mwe2ExecutionEngine.java:142)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.inCase(Mwe2ExecutionEngine.java:114)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:296)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.internalSwitch(Mwe2ExecutionEngine.java:66)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.inCase(Mwe2ExecutionEngine.java:80)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.xtext.util.PolymorphicDispatcher.invoke(PolymorphicDispatcher.java:296)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.internalSwitch(Mwe2ExecutionEngine.java:66)
at org.eclipse.emf.mwe2.language.factory.Mwe2ExecutionEngine.create(Mwe2ExecutionEngine.java:62)
at org.eclipse.emf.mwe2.launch.runtime.Mwe2Runner.run(Mwe2Runner.java:93)
... 4 more
Caused by: java.lang.reflect.InvocationTargetException
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at org.eclipse.emf.mwe2.language.factory.SettingProviderImpl$1$1.setValue(SettingProviderImpl.java:54)
... 29 more
Caused by: org.eclipse.emf.mwe.core.ConfigurationException: Couldn't find an interface metamodel.MetamodelPackage
at org.eclipse.emf.mwe.utils.StandaloneSetup.addRegisterGeneratedEPackage(StandaloneSetup.java:430)
... 34 more
am new to xtext and eclipse, and appreciate any help to solve my errors.
Thanks
AYMEN

Answer 1

can you check your workflow. You need to have the scanClassPath = true
and to register your meta-model. See the following example :
Workflow {
bean = StandaloneSetup {
scanClassPath = true
platformUri = "${runtimeProject}/.."
}
....
....
component = Generator {
....
language = auto-inject {
loadedResource = "platform:/resource/org.eclipse.emf.ecore/model/Ecore.genmodel"
....
}
}