Design Patterns:Elements of Rousable Object-Oriented Software Guide to Readers This book has two main parts.The tirst part (Chapters 1 and 2)desczibes wha design patterns are and how they help you designobject-oriented software.It includes a design case study thatdemonstrates how design patterns apply in practice The second partof the book (Chapters 3,4,and 5)is a catalog of the actual designpatterns. The catalog makes up the majority of the book.Its chapters dividethe design patterns into three types:creational,structural,andbehavioral.You can use the catalog in several ways.You can readthe catalog from start to finish,or you can just browse from patternto pattern.Another approach is to study one of the chapters.Thatwill help you see how closely related patterns distinguish themselves. You can use the references between the patterns as a logicalroute through the catalog.Thi app oach will give you insightinto how patterns relate to each other how they can be combinedwith other patterns,and which patterns work well together Figure 1.1(page 23)depicts these references graphically. Yet another way to read the catalog is to use a more problem-directedapproach. skip to section 1.6 (page 23)to read about some common problems in designing reusable object-orientedsoftware:then read the patterns that address these problems Somepeople read the catalog through first and then use aproblem-directed approach to apply the patterns to their projects. If you aren't an experienced object-oriented designer,then start withthe simplest and most common patterns: Abstract Factory (page 99) Adapter (157 ·Composite(183】 ·Decorator(196) ·Factory Method(121) Obser er1326) ·Strategy(349) Template Method(360 It's hard to find an object-oriented system that doesn't use at leasta couple of these patterns,and large systems use nearly all of them.This subset will help you understand design patterns in particular andgood object-oriented design in general. 10 Design Patterns: Elements of Reusable Object-Oriented Software 10 Guide to Readers This book has two main parts. The first part (Chapters 1 and 2)describes what design patterns are and how they help you designobject-oriented software. It includes a design case study thatdemonstrates how design patterns apply in practice. The second partof the book (Chapters 3, 4, and 5) is a catalog of the actual designpatterns. The catalog makes up the majority of the book. Its chapters dividethe design patterns into three types: creational, structural, andbehavioral. You can use the catalog in several ways. You can readthe catalog from start to finish, or you can just browse from patternto pattern. Another approach is to study one of the chapters. Thatwill help you see how closely related patterns distinguish themselves. You can use the references between the patterns as a logicalroute through the catalog. This approach will give you insightinto how patterns relate to each other, how they can be combinedwith other patterns, and which patterns work well together. Figure 1.1(page 23) depicts these references graphically. Yet another way to read the catalog is to use a more problem-directedapproach. Skip to Section 1.6 (page 23) to read about some common problems in designing reusable object-orientedsoftware; then read the patterns that address these problems. Somepeople read the catalog through first and then use aproblem-directed approach to apply the patterns to their projects. If you aren't an experienced object-oriented designer, then start withthe simplest and most common patterns: · Abstract Factory (page 99) · Adapter (157) · Composite (183) · Decorator (196) · Factory Method (121) · Observer (326) · Strategy (349) · Template Method (360) It's hard to find an object-oriented system that doesn't use at leasta couple of these patterns, and large systems use nearly all of them.This subset will help you understand design patterns in particular andgood object-oriented design in general