This chapter has shown you the benefits of mixing MSMQ with COM+ to create applications that work asynchronously. Many of these applications will see use in situations where the client and server might not exist at the same time, such as when a user spends a lot of time on the road. The disconnected application is the most impressive form of this technology but not the only form. We also discussed a number of other uses, such as balancing the server load so that it can continue to work during off-peak hours.
The problem with using this technology is that it comes at a pricea small performance hit. In addition, you have to consider the added complexity of working with MSMQ, versus working directly with the component. Thats where the decision point is for the developer. You need to determine whether the benefits of using MSMQ outweigh the potential problems. Sometimes, the best way to learn about the various problems is to build the same simple application twiceonce with and once without MSMQ support so that you can see the differences in a controlled environment. In fact, building a double test application is one thing you should try now that youve read this chapter.
Chapter 10 takes you through the process of creating applications that use subscriptions. This form of disconnected application works much the same as any broadcast application you might have worked with in the past, such as the electronic newsletters that are so popular today. The publisher is a component that sends out data but doesnt care where the data goes. The subscriber is a client who receives the data but doesnt really care who published it. In between is COM+, which is managing the publication and subscription process.