Rich clients

A three-tiered architecture includes one more node between the client and the database server—the middle tier. In a three-tiered architecture, business logic is offloaded from the client and the database server nodes to the middle tier. In fact, you can choose to further distribute the business logic among more than one middle tier node and still call it a three-tiered (or K-tiered) architecture because the idea is similar. Note that the tiers do not have to be physically separated. You can have both the middle tier server and the database server collocated on the same physical computer but running in different processes with separate memory spaces. Modem hardware architecture can partition a single hardware box into multiple virtually separate computers or domains. Typically, a three-tiered architecture supports a Web-based thin client although it can also work with a rich client. 

Both client-server and three-tired architectures can be developed using either Java or. NET technology, although. NET is a more natural choice for a rich client on Windows-based client PCs. It is also possible to take a hybrid approach—develop rich client in. NET but business logic in Java, and integrate both using SOAP-based Web services. MDL s Isentris, for example, takes the hybrid approach. 

From the top, the client layer resides on an end user s desktop, laptop, or handheld device, which is typically, but not limited to, a Windows PC with a Web browser. Usually a Web-based client layer is called thin client, which is lightweight. The programs that run inside the browser are typically JavaScript, VB Script, Java Applets, ActiveX, or Web browser plug-in. Using a rich client such as. NET or Java Swing is another choice, although this book focuses on a Web-based architecture. 

Web-based systems offer several advantages over rich client easy to deploy and access, easy to scale (by adding more hardware resources to the application server), and shared computing resources (CPUs, memory, database connections). However, most of the information this book presents is not limited to Web-based applications. It promotes the loosely coupled Presentation Layer and Domain Layer so that business logic can be reused no matter what GUI technology is being used. 

The defendant claimed he was investing money for an anonymous rich client through land purchases which were supposed to have been made from 1958 through 1966. Over a half a million dollars of taxable income was involved. The government claimed the defendant was investing his own money and was using the rich client scheme to avoid paying the tax. 

The client has asked for a recommended formulation for a luxurious soap bar, based solely on vegetable fats (Figure 9.2). A high-quality palm-coconut base that is widely available in Europe should be suitable, but it was felt that such a premium product should contain some additional materials to convey added value . Thus, a powdered cationic polymer is incorporated, which deposits a moisturizing film on the skin and helps to promote a rich, creamy lather. Titanium dioxide, a standard additive to any soap, provides greater opacity (and, to some extent, whiteness) to the bar and a variety of pigment pastes, which are... 

Prepd by condensation of teri-pemanol or 2-methyl -3-butanol with phenol in the presence of aluminum chloride Huston, Hsieh, J. Am. Chem. Soc. 58, 439 (1936) Huston et al.. ibid. 67, 899 (1945). Physical properties Pardee, Wein-rich, lnd. Eng. Client. 36, 595 (1944). 

Thiazide diuretics do not cause excess loss of potassium, but the client shonld be encouraged to eat potassium-rich foods to prevent hypokalemia, which may occur as a result of increased urination. 

The client should not eat potassium-rich foods because this medication retains potassium. 

Figure 19.4- Rich communication channels and the reach of clients for a given fixed cost...

I then explained to the plant manager that the flow of gas through the orifice plate flow meter had always been constant. The smaller indicated flow of hydrogen-rich gas was not real. My client had forgotten to adjust the flow meter for the lighter gas composition. 

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