Design Patterns

• DAO - Data Access Object. Objects which handle storage of data e.g. in a database
• Template - Dividing interface from implementation

• Separation Of Concerns

A design pattern usually consists of:

• a name - the identifier for the pattern. Any aliases must also be listed.
  
• a goal - what the pattern aims to achieve (sometimes described as forces)
  
• the description - describes how the pattern works
  
• the implementation - making the pattern work in practice
  
• cases - successful applications of the pattern

Consists of:

• participants - the objects that interact

Cross Cutting Concern

http://java.sun.com/developer/technicalArticles/J2EE/patterns/