[mdr-users] RE: NullPointer Exception with MDR StandAlone

 Hallo Luiz Felipe,

I think I had a similar problem. I have denoted the whole path of the
storage file. For example :

private String storageFile= 
"C:\\myApplication\\mdrStorageFiles\\MDRStorage";

That works, but I must change it someday because it is not very elegant.
	
 Another thing is that I  sloved the access to the standalone NBMDR in
another way. Thereby I  look about the example on the NBMDR site and the
source code of the UML2MOF tool that is also on the netbeans site. 
I didn't use this constructor :
MDRepository repository = new NBMDRepositoryImpl(properties);

I use the following code to get access to the standalone nbmdr

// here I start the initalization
public void initMDR(){
    	
    	manager=getMDRManager();
    	repository=manager.getDefaultRepository();
    	
        if((repository.getExtent(modelPackageName))==null){
    		
    		instantiateModelPackage();
    		createExtent("Default");
    	}
    	
    	
}

// this is nearly the same code that was used in the uml2mof tool
public MDRManager getMDRManager() {
        
        	ClassLoader oldLoader = Thread.currentThread(). 
            getContextClassLoader();                
        	Thread.currentThread().setContextClassLoader( this.getClass().
            getClassLoader() );
                
        	if ( storageFile != null ) {
            	System.getProperties().
                  put( "org.netbeans.mdr.persistence.Dir", storageFile );
        	}
        
        	MDRManager mm = MDRManager.getDefault();
        
        	Thread.currentThread().setContextClassLoader( oldLoader );
            
        	return mm;
}

//  this method  initializes the modelpackage
private void instantiateModelPackage(){
		
	ModelPackage modelpackage;
	try
        {
        	
        	repository.beginTrans( true );
			try{
				modelpackage = ( ModelPackage) repository.  
                        createExtent(modelPackageName);
							
				if(modelpackage!=null){
			
				      try{
    	
    				XMIReader xmiReader = 
                        XMIReaderFactory.getDefault().createXMIReader();
        			xmiReader.read( new File(metaModelFile).toURL().
                        toString(), repository.getExtent("MetaModel"));
        				  }catch(Exception e){	
        	                    System.out.println("The XMI file of the 
                                 MetaModel couldn`t be read  "+e);
        					   repository.endTrans(true);
        				    }
    				}
		   }catch(CreationFailedException e){
    				System.out.println("The extent couldn´t be created "+e);
    				repository.endTrans(true);
		     }
	    }finally {
    			repository.endTrans();
		 }
	}

/* with method creates the extent that I use for my application

public void createExtent(String name)
{   
        	
    try
    {
        	
        repository.beginTrans( true );
        try
        {
        			
        repository.createExtent(name, getModelPackage(modelPackageName));  
    				System.out.println("The extent could be created");
    		}catch(CreationFailedException e)
    	    {
    		System.out.println("The extent couldn´t be created "+e);
						repository.endTrans(true);
		}
	     } finally {
    			repository.endTrans();
	 }
}	

Regards
Ludger


 

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