Continue. .
CORBA component model: Part 1, evolving to component middleware (Component MiddleWare)
The CORBA Component Model, C / C Uses Journal February 2004
Douglas C. Schmidt and Steve Vinoski
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The use of object-oriented technology is also related to many similar zero-smaller problems, which requires developers to use the coding convention and style of the developers.
Together. So, this approach requires a major work to surpass the original objects and events of existing support services when developing large systems. Need to have a way to put larger units
Packaged together, these units consist of an existing part of the high-level performance (sometimes different types), including their supported properties. For example, a typical performance may need to trigger all types of objects, such as transaction processing, management order and receiving state change, and fault tolerance processing, etc.
. If they implement and available, they need to be carefully engaged separately in each instance, which is a full module that handles some particular part of the entire application.
The Object Management Organization (OMA) defines the advanced DOC middleware standard for the build simple distribution program in the CORBA 2.x specification. Corba 2.x
Focus on the interface, essentially, interface (interface) established the client and server agreed, that is, how the client observes and access the service provided by the server. Corba despite
There is an advanced performance, however, the CORBA 2.x standard has the following limitations: 1, lack of functional boundary. CORBA 2.x object model puts all interfaces as the form of a client / server. However, this object model is not
Provide a standard assembly mechanism to reduce the dependence performed between collaborative objects. For example, objects need to be clearly perceived and connected to other objects that they want to rely on. but,
Establish complex distributed applications, developers must clearly plan the connection between the interdependence service and object interfaces, but this is some extra work - not crisp
Weak unreable realization. 2, scalability. Since the components are described relative to the object, inheritance is not so close to the meaning of achieving the polymorphism. Object is an instance of the unit, package type, pickup
The mouth and behavior are the model of the problem of the problem domain used (possibly physical). Typically they are implemented in a specific language and have some layout
The objects of each interaction must be met. Conversely, one component does not need to be expressed as a class that is implemented in a particular language, or shares binary compatibility with other components (although practical
Can do this). Thus, the component can be seen as a functional provider, which can be replaced by the same components written in other languages. This extensibility is convenient, by expansion interface design mode (e
Xtension Interface Design Pattern, define a set of standard protocols to create, combine, and expand interactions (Groups of Interacting Components)
. 3. High-level execution environment. The component model defines the runtime execution environment - "container", that is, the operation is more abstract than accessible through object access. Container operating environment is a component definition and strong
The strategy provides additional control levels. Conversely, the direct dependence of the lower constructor will force the component function evolution from the runtime to separate the evolution of the lower structure.
(to be continued...)
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