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Explain Facade Design Pattern in Java? |
The objective of Facade pattern is to make a complex system simple. It is achieved by providing a unified or general interface, which is a higher layer to these subsystems.Facade pattern decouples subsystems, reduce its dependency, and improve portability,makes an entry point to your subsystems and hides clients from subsystem components and their implementation.
JDBC design is a good example of Façade pattern. A database design is complicated. JDBC is used to connect the database and manipulate data without exposing details to the clients.
A client is exposed to certain set of methods like just getting a single instance of database connection or closing it when not required.
Another possibility is designing security of a system with Façade pattern. Clients' authorization to access information may be classified. General users may be allowed to access general information, special guests may be allowed to access more information,administrators and executives may be allowed to access the most important information. These subsystems may be generalized by oneinterface. The identified users may be directed to the relatedsubsystems.Labels: Design patterns |
posted by javapeople @ 9/22/2008 09:00:00 AM   |
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| Thursday, September 18, 2008 |
What Is Caster Mapping? |
Castor XML mapping is a way to simplify the binding of java classes to XML document. It allows to transform the data contained in a java object model into/from an XML document.
Although it is possible to rely on Castor's default behavior to marshal and unmarshal Java objects into an XML document, it might be necessary to have more control over this behavior. For example, if a Java object model already exists, Castor XML Mapping can be used as a bridge between the XML document and that Java object model.
Castor allows one to specify some of its marshalling/unmarshalling behavior using a mapping file. This file gives explicit information to Castor on how a given XML document and a given set of Java objects relate to each other...........http://www.castor.org/xml-mapping.html |
| posted by javapeople @ 9/18/2008 04:52:00 PM |
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