[一]Head First设计模式之【策略模式】（鸭子设计的优化历程）

publicabstractclassDuck{
FlyBehaviorflyBehavior;
QuackBehaviorquackBehavior;
publicDuck(){
}
publicabstractvoiddisplay();
publicvoidperformFly(){
flyBehavior.fly();
}
publicvoidperformQuack(){
quackBehavior.quack();
}
publicvoidswim(){
System.out.println(“Allducksfloat,evendecoys!”);
}

publicvoidsetFlyBehavior(FlyBehaviorfb){
flyBehavior=fb;
}
publicvoidsetQuackBehavior(QuackBehaviorqb){
quackBehavior=qb;
}

}

publicinterfaceFlyBehavior{
publicvoidfly();
}
publicclassFlyWithWingsimplementsFlyBehavior{
publicvoidfly(){
System.out.println(“I’mflying!!”);
}
}
publicclassFlyNoWayimplementsFlyBehavior{
publicvoidfly(){
System.out.println(“Ican’tfly”);
}
}

publicclassFlyRocketPoweredimplementsFlyBehavior{
publicvoidfly(){
System.out.println(“I’mflyingwitharocket!”);
}
}

publicinterfaceQuackBehavior{
publicvoidquack();
}
publicclassQuackimplementsQuackBehavior{
publicvoidquack(){
System.out.println(“Quack”);}
}
publicclassMuteQuackimplementsQuackBehavior{
publicvoidquack(){
System.out.println(“<<Silence>>”);}
}
publicclassSqueakimplementsQuackBehavior{
publicvoidquack(){
System.out.println(“Squeak”);}
}

publicclassModelDuckextendsDuck{
publicModelDuck(){
flyBehavior=newFlyNoWay();
quackBehavior=newQuack();
}
publicvoiddisplay(){
System.out.println(“I’mamodelduck”);}
}

publicclassMiniDuckSimulator{
publicstaticvoidmain(String[]args){
Duckmallard=newMallardDuck();
mallard.performQuack();
mallard.performFly();

Duckmodel=newModelDuck();
model.performFly();
model.setFlyBehavior(newFlyRocketPowered());
model.performFly();

}
}