Design Patterns demonstrates how software developers can improve the performance, maintainability, portability, and scalability of their code through the use of the Gang of Four design patterns. After a discussion of patterns methodology, reasons for using design patterns, the book delves into each of the 23 patterns.Each pattern section gives a detailed description of the pattern, refactored from either Boolean logic or simpler, less-maintainable code that you might encounter in the real world, and shows readers how to use the pattern in their code. The text walks readers through making the move from current code to the pattern, lists the benefits of using the pattern, and shows how the pattern performs after the refactoring effort, with a goal throughout of providing practical implementations.