JavaCh 21 Generics 2011 05 27 Outline Generics

  • Slides: 15
Download presentation
Java@Ch 21. Generics 2011. 05. 27

Java@Ch 21. Generics 2011. 05. 27

Outline • Generics • Defining Generic Classes and Interfaces • Generic Methods [Sample code]

Outline • Generics • Defining Generic Classes and Interfaces • Generic Methods [Sample code] Generic. Stack. java 、 Generic. Method. Demo. java 、 Wild. Card. Demo 1. java、Wild. Card. Demo 2. java、 Wild. Card. Demo 3. java

Generics • Java allow you to define generic classes, interface, and methods <Prior to

Generics • Java allow you to define generic classes, interface, and methods <Prior to JDK 1. 5> Comparable c = new Date(); System. out. println(c. compare. To(“red”)); <JDK 1. 5> Comparable<Date> c = new Date(); System. out. println(c. compare. To(“red”)); Compile 會過 但執行會錯 因為Date與String 型態不符 Compile 時會檢查 Date與String型態 是否符合

Defining Generic Classes and Interfaces 程式範例: Generic. Stack. java

Defining Generic Classes and Interfaces 程式範例: Generic. Stack. java

使用Generic type 優點: Certain errors can be detected at compile time rather than at

使用Generic type 優點: Certain errors can be detected at compile time rather than at runtime. 易犯的錯: Constructor of Generic. Stack should be defined as (X) (O) public Generic. Stack<E>() public Generic. Stack()

Generic Methods 程式範例: Generic. Method. Demo. java

Generic Methods 程式範例: Generic. Method. Demo. java

Wildcard Generic Type 程式範例: Wild. Card. Demo 1. java Wild. Card. Demo 2. java

Wildcard Generic Type 程式範例: Wild. Card. Demo 1. java Wild. Card. Demo 2. java Wild. Card. Demo 3. java

A wildcard generic type has three forms : 1. ? Unbounded wildcard (same as

A wildcard generic type has three forms : 1. ? Unbounded wildcard (same as ? extends Object) 2. ? extends T bounded wildcard 3. ? super T lower-bound wildcard (T is generic type)

Generics and collections Generics and collections Generics andGenerics and collections Generics and collections Generics and
Generics and collections Generics and collections Generics andGenerics and collections Generics and collections Generics and
Generics Ashima Wadhwa What are generics Generics wereGenerics Ashima Wadhwa What are generics Generics were
JavaCh 15 Graphics 2011 04 01 Outline GraphicalJavaCh 15 Graphics 2011 04 01 Outline Graphical
JavaCh 19 Binary IO 2011 05 06 OutlineJavaCh 19 Binary IO 2011 05 06 Outline
JavaCh 5 Methods 2010 11 05 Outline OverloadingJavaCh 5 Methods 2010 11 05 Outline Overloading
JavaCh 14 Abstract Classes And Interfaces 2011 03JavaCh 14 Abstract Classes And Interfaces 2011 03
Generics Contents Introduction Benefits of Generics Generic ClassesGenerics Contents Introduction Benefits of Generics Generic Classes
Generics Generics n n A generic is aGenerics Generics n n A generic is a
Generics A Brief Review Generics n n AGenerics A Brief Review Generics n n A
Generics What is Generics Collections can store ObjectsGenerics What is Generics Collections can store Objects
1 Chapter 21 Generics 2 Generics Overview Generic1 Chapter 21 Generics 2 Generics Overview Generic
Generics Collections Why do we need Generics AnotherGenerics Collections Why do we need Generics Another
Authorized Generics Good For Everyone Even Generics JeromeAuthorized Generics Good For Everyone Even Generics Jerome