<primary resources>
        <elements map key="1">
          <value id ="1">
            <keywords tags="foo">
          </value>
        </elements map>
      </primary resources>

     <primary resources>
        <elements map key="1">
          <value id ="1">
            <keywords tags="foo">
          </value>
        </elements map>
        <elements map key="2">
          <value id ="2">
            <keywords tags="bar">
          </value>
        </elements map>
      </primary resources>

     <primary resources>
        <elements map key="1">
          <value id ="1">
            <keywords tags="foo">
          </value>
        </elements map>
        <elements map key="2">
          <value id ="2">
            <keywords tags="bar">
          </value>
        </elements map>
        <elements map key="1">
          <value id ="1">
            <keywords tags="foo">
          </value>
        </elements map>
        <elements map key="2">
          <value id ="2">
            <keywords tags="bar">
          </value>
        </elements map>
        <elements map key="3">
          <value id ="3">
            <keywords tags="foo">
          </value>
        </elements map>
      </primary resources>

public CoreServicesResources LoadModel() throws IOException 
{	
    CoreServicesResources coreServicesResources;
    PrimaryResources primaryResources;
		
    ResourceSet resourceSet = new ResourceSetImpl();
    resourceSet.getResourceFactoryRegistry().getExtensionToFactoryMap().put("model", new XMIResourceFactoryImpl());
		
    File elements = new File(ResourcesPlugin.getWorkspace().getRoot().getProject(DEFAULT_PROJECT_NAME).getLocationURI().getPath().toString() + "/elements.model");	    
    URI fileURI = URI.createFileURI(elements.getAbsolutePath());				
    Resource resource = resourceSet.createResource(fileURI);	    
	    
    // If there is a model file, load it
    if(resourceSet.getURIConverter().exists(fileURI, null))
    {
        resource.load(null);
        coreServicesResources = (CoreServicesResources)resource.getContents().get(0);			
    }
    else // else construct empty model
    {	    			
        coreServicesResources = CoreFactory.eINSTANCE.createCoreServicesResources();
        primaryResources = CoreFactory.eINSTANCE.createPrimaryResources();	
        coreServicesResources.setPrimaryResources(primaryResources);
    }

    resourceSet.getResources().remove(resource); 	    
    return coreServicesResources;
}

	/**
	 * <!-- begin-user-doc -->
	 * Overridden the default in order to create a singleton.
	 * <!-- end-user-doc --
	 */
	@Override	
	public PrimaryResources createPrimaryResources() {
		if (primaryResources == null) {
			primaryResources = new PrimaryResourcesImpl();
		}
		return primaryResources;
	}