code: public static boolean hasAllRequiredImports( Instance instance, Logger logger ) {
  
  		boolean haveAllImports = true;
  		for( String facetOrComponentName : VariableHelpers.findPrefixesForMandatoryImportedVariables( instance )) {
  			Collection<Import> imports = instance.getImports().get( facetOrComponentName );
  			if( imports != null && ! imports.isEmpty())
  				continue;
  
  			haveAllImports = false;
  			if( logger != null )
  				logger.fine( InstanceHelpers.computeInstancePath( instance ) + " is still missing dependencies '" + facetOrComponentName + ".*'." );
  
  			break;
  		}
  
  		return haveAllImports;
  	}
docs: Determines whether an instance has all the imports it needs.
  <p>
  Master of Obvious said:<br>
  By definition, optional imports are not considered to be required.
  </p>
  
  @param instance a non-null instance
  @param logger a logger (can be null)
  @return true if all its (mandatory) imports are resolved, false otherwise