Re: [mdr-users] NullPointerException

Hello,

	You need to load your metamodel first... Take a look on the following 
code (it uses SPEM metamodel, but the idea is almost the same for UML - 
In the case of UML you will need to search for a package named Model and 
instantiate it...):

// Init Repository with SPEM metamodel (M2)
ModelPackage modelPackage = 
(ModelPackage)repository.createExtent(METAMODEL_EXTENT);
URL xmiSpemMetamodel = this.getClass().getResource(SPEM_METAMODEL);
xmiReader.read(xmiSpemMetamodel.toString(), modelPackage);			

// Init the SPEM model extent (M1)
Iterator iterator = modelPackage.getMofPackage().refAllOfClass().iterator();
while (iterator.hasNext()) {
	MofPackage mofPackage = (MofPackage)iterator.next();
	if ("SPEM".equals(mofPackage.getName())) {
		spemPackage = (SpemPackage)repository.createExtent(MODEL_EXTENT, 
mofPackage);
		URL xmiSpemModel = this.getClass().getResource(SPEM_MODEL);
		xmiReader.read(xmiSpemModel.toString(), spemPackage);
		break;
	}
}

	Leo

Cheng yong wrote:
> Hello, everyone,
>  
> I'm now making my own example according to the online document and try 
> to figure out how the MDR works. Now I have got an NullPointerException 
> Error. Can anyone help me?
>  
> What I did is as following:
> 1. NetBeans IDE 3.5.1: imported Metadata UML 1.4 (01-02-15_Diff.xml) and 
> generated the JMI Interfaces.
> 2. Eclipse 3.1: created a new project, added all .jar files which I can 
> find in the installation folder, imported all generated files.
> 3. Eclipse 3.1: created a new demo class,
>  
> package demo;
> import java.io.OutputStream;
> import java.util.Iterator;
> import org.netbeans.api.mdr.MDRManager;
> import org.netbeans.api.mdr.MDRepository;
> import org.netbeans.api.xmi.XMIWriterFactory;
> import org.omg.uml.*;
> import org.omg.uml.behavioralelements.activitygraphs.*;
> public class Demo {
>    
>     public static void main(String[] args) {
>        
>         OutputStream out = null;
> 
>         MDRepository repository = 
> MDRManager.getDefault().getDefaultRepository();
> 
>         UmlPackage extent = (UmlPackage) repository.getExtent("Projects 
> metadata");
>         try{
>             
> XMIWriterFactory.getDefault().createXMIWriter().write(out,extent,"1.2");
>             System.out.println(out.toString());
>         } catch(Exception e){
>             System.out.println("ERROR!");
>         }
>     }
> }
> 4. Eclipse 3.1: runed the demo, got the error:
>  
> java.lang.NullPointerException
>  at 
> org.netbeans.modules.mdr.MDRManagerImpl.refreshChildren(MDRManagerImpl.java:61)
>  at org.netbeans.modules.mdr.MDRManagerImpl.init(MDRManagerImpl.java:84)
>  at 
> org.netbeans.modules.mdr.MDRManagerImpl.getRepository(MDRManagerImpl.java:94)
>  at 
> org.netbeans.modules.mdr.MDRManagerImpl.getDefaultRepository(MDRManagerImpl.java:105)
>  at demo.Demo.main(Demo.java:18)
> Exception in thread "main"
>  
> thanks
>  
> Lucia
> 
> ------------------------------------------------------------------------
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