Hey Group,<o:p></o:p>
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Today we will discuss ECC features of COM+. These features were not present in MTS and but are present in COM+ Services.<o:p></o:p>
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Events: - This is a new service that has been added in COM+. This service one has to register an event interface with COM+ Services. Then you register classes that raise this event. These classes are called as publishers. After registering publishers you create classes that handle the raised events. These are called as subscribers. This model is also called as publisher-subscriber model. Hence when publisher raises an event COM+ will notify all its subscribers.<o:p></o:p>
Here COM+ acts as an intermediate layer between publisher class and subscriber classes so that they do not refer each other directly.<o:p></o:p>
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Component Message Queuing: - In the past a lot of times there have been instances when we have faced problems of the component not being available or the component being offline. For these situations we had to provide some error handling logic. But COM+ now provides us with a new option for queuing requests for any offline component so that when the component comes online it can forward the request to the component. All these things happen behind the scene and the client is completely unaware of this. As soon as the component available the requests are executed and the results are sent to the client.<o:p></o:p>
But if we have looking forward for this option then we should have robust error handling coz it should not happen the client is waiting for prolonged period of time or even if the component is available the request raised an error or exception.<o:p></o:p>
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Component Load Balancing: - This is one of the most important feature of COM+. Component load balancing is used to cater a large number of clients by balancing client requests between COM+ Components. When one feels that one server is not enough to provide a quick response to the clients and the client response time is increasing, you can have multiple servers hosting your components. Component Load balancing is used to balance the number requests across servers. It distributes client requests across component servers thus enabling a fast and better performance and reducing the response time.<o:p></o:p>
If we were to consider component load balancing we should keep in mind the fact the request may not go to the same server every time. Hence the architecture of all our objects should stateless. I had discussed this before also when we checked out JIT and object pooling. Object pooling is not available when Component Load balancing is done for obvious reasons coz you do not where the previous request was executed.<o:p></o:p>
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Tomorrow we will check out how to go about implementing COM+ in NET.
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-- Please post your queries and comments for my articles in the user group for the benefit of all. I hope this step from my end is helpful to all of us. You can find all articles written by me at my personal blog http://spaces.msn.com/members/nasha.
Regards,
Namratha (Nasha)<o:p></o:p>
