Chapter 20 corba fm
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Soft computing Lab Mannual, Distributed systems
| Figure 20.7 IDL module Whiteboard. module Whiteboard { struct Rectangle{ ...} ; struct GraphicalObject { ...}; interface Shape { ...}; typedef sequence interface ShapeList { ...}; }; SECTION 20.2 CORBA RMI 841 the exception contains no variables. However, exceptions maybe defined to contain variables, for example: exception FullException {GraphicalObject g }; When an exception that contains variables is raised, the server may use the variables to return information to the client about the context of the exception. CORBA can also produce system exceptions relating to problems with servers, such as their being too busy or unable to be activated, problems with communication and client-side problems. Client programs should handle user-defined and system exceptions. The optional context expression is used to supply mappings from string names to string values. See Baker [1997] for an explanation of context. IDL types ◊ IDL supports fifteen primitive types, which include short (bit, long (32- bit, unsigned short, unsigned long, float (bit, double (bit, char, boolean (TRUE, FALSE, octet (8-bit), and any (which can represent any primitive or constructed type. Constants of most of the primitive types and constant strings maybe declared, using the const keyword. IDL provides a special type called Object, whose values are remote object references. If a parameter or result is of type Object, then the corresponding argument may refer to any CORBA object. IDL’s constructed types are described in Figure 20.8, all of which are passed by value in arguments and results. All arrays or sequences used as arguments must be defined in typedefs. None of the primitive or constructed data types can contain references. Download 234.39 Kb. Share with your friends:
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