if ( structDict == null ) populateStructDict( );
assert structDict != null;
	static IStructure createStructure( StructureDefn structDefn )	{		assert structDefn != null;		if ( structDict == null )			populateStructDict( );		IStructure struct = null;		try		{			Class c = (Class) structDict.get( structDefn.getName( )					.toLowerCase( ) );			assert c != null;			struct = (IStructure) c.newInstance( );		}		catch ( InstantiationException e )		{			assert false;		}		catch ( IllegalAccessException e )		{			assert false;		}		return struct;	}