COM principle and application----COM development--com+

1, COM +

Because of historical reasons, COM, DCOM and MTS are not very harmonious with each other, it is difficult to form a unified whole. COM + has effectively unified these three, forming a new, powerful component architecture.

COM + is not a new version of COM, but a new development of COM, or a higher level of COM application. COM + 's underlying structure is still based on COM, which almost embraces all of COM's content. COM + promotes component software to the application tier rather than the underlying software architecture, which allows the Component object model to be built on the application tier with the support of the operating system, leaving the underlying details of all components to the operating system, so that COM + is more closely integrated with the operating system.

COM + is no longer limited to COM component technology, it is more focused on the design and implementation of distributed network applications, has become a Microsoft system platform strategy as a part of.

2. Windows DNA Strategy

Windows DNA, distributed internet Application architecture, distributed internet Application architecture.

3. COM + basic structure

COM + provides a better component management environment than MTS, and COM + Explorer also uses an MMC standard interface.

COM and MTS Store all of the configuration information for a component in the Windows system registry, while COM + saves component information in a new database called the COM + catalog (COM + Catalog).

4. Object Environment

COM + provides an object context for each object.

5. COM + system services--com+ to column components

The interaction between a COM client and a remote component is based on RPC connectivity. In addition to supporting this approach based on RPC connectivity, COM + also supports a message based communication process that effectively leaves customers and component lifetimes separated from the COM + Queue component service. The queue component uses the underlying message system MSMQ (Microsoft message Queue Server,microsoft Messaging Queuing service system). COM + applications can support both synchronous and asynchronous invocation methods in a transparent manner.

6. COM + system service--com+ event model

COM not only defines the communication process that the client invokes the Component object, but also defines the reverse communication process, which is the COM connection object mechanism.

The COM + event model improves COM's connectivity object mechanism, which employs a multi-channel publish/subscribe event mechanism.

7. COM + system Services-load balancing

COM + provides a load-balancing service that enables dynamic load balancing in a transparent manner. The load-balancing features of COM + applications do not require code to support, and client and component programs can be implemented in the usual way.

8. COM + system Services--memory database (IMDB)

COM + 's memory databases (imdb,in memory database) service is a new service that holds non-persistent state information for applications. The function of IMDB is to optimize the data query and , it can load the data table in the background database system, or can load the application's non-persistent data information.

9. COM + system Services--Other

Transaction attributes, Security, COM + object pooling, and management services.