15. Why Goovy？
• 更多简洁代码的示例
– System.out.println => println
– 可选的return
– GString: "${i++}: $it"
– GroovyBean（左）让JavaBean（右）更简洁
class MyBean{
class MyBean{ private int a
int a public int getA(){ return a}
} public void setA(int a){this.a = a}
}
21. Why Goovy？
• Duck Typing：更高级的多态
– 如果走路像鸭子，叫声像鸭子，那它就是鸭子
class Rectangle{
def draw(){
println "This is rectangle"
}
}
class Square{
def draw(){
println "This is Square"
}
}
def draw(painter){
painter.draw()
}
draw(new Rectangle())
draw(new Square())
22. Why Goovy？
• GPars：并发编程其实也不是那么难 :）
– 从Groovy 1.8起，作为扩展包随Groovy发布。
– 对多种并发编程模型提供了简洁的DSL：
• Actor、STM、Agent、CSP、Data Flow等
final Actor actor = new DynamicDispatchActor({
when {String msg -> println 'A String'; reply 'Thanks'}
when {Double msg -> println 'A Double'; reply 'Thanks'}
when {msg -> println 'A something ...'; reply 'What was that?'}
})
actor.start()
