Design Patterns in WCS

• MVC Design Pattern               
  Model View Controller pattern is used to separate the business logic from its presentation. View corresponds to JSP's, Controller corresponds to struts framework/BOD framework and Model corresponds to all back end objects used for processing like Accessbeans/EJB’s.
   
• Factory Design pattern
  A factory pattern can be used to create an object of any one of sub-classes depending on the input data provided. This is used when we call another command from a command.
  Eg., SampleCmd sampleCmd = (SampleCmd) CommandFactory.createCommand("com.test.commands.SampleCmd",getStoreId());


• Command Design Pattern
  It is used to execute a command with a blackbox view of it. The “command” is a black box to the “client”. All the client does is call “execute ()” on the opaque object.
  Eg,. sampleCmd.execute();
  
  
• Display Design pattern
  In WCS, view names are used to display the response (JSP) to the client. There may be a need to pass different response based on clients.
  E.g., <forward className="com.ibm.commerce.struts.ECActionForward" name="SampleView/10161/-22" path="/test/SampleView_View1.jsp" />
  
  
• Singleton Design pattern
  A singleton pattern ensures that only one object instance is created by the JVM at a time for a class, which is taken care by the out of the box framework. Eg. ECCommandTarget class