//装饰模式
interface MonkeyKing {
    function change();
}

class Monkey implements MonkeyKing {
    function change() {
        trace("this is a monkey");
    }
    function say() {
        trace("he is talking");
    }
}
class MonkeyChange implements MonkeyKing {
    private var monkey:MonkeyKing;
    public function Change(m:MonkeyKing) {
        monkey = m;
    }
    function change() {
        trace("begin change");
    }
}
class Fish extends MonkeyChange {
    function Fish(m:MonkeyKing) {
        monkey = m;
    }
    function change() {
        monkey.change();
        super.change()
        trace("a fish");
    }
    function water() {
        trace("he can in water");
    }
}
class Bird extends MonkeyChange {
    function Bird(m:MonkeyKing) {
        monkey = m;
    }
    function change() {
        monkey.change();
        super.change();
        trace("a bird");
    }
    function fly() {
        trace("he can fly");
    }
}

test1:
var monkey:MonkeyKing = new Monkey();
trace("变鱼");
var fish:MonkeyKing = new Fish(monkey);
fish.change();
trace("变鸟");
var bird:MonkeyKing = new Bird(monkey);
bird.change();
trace("先变鱼，后变鸟");
var bird:MonkeyKing = new Bird(fish);
bird.change();
/*
变鱼
this is a monkey
begin change
a fish
变鸟
this is a monkey
begin change
a bird
先变鱼，后变鸟
this is a monkey
begin change
a fish
begin change
a bird
*/
var monkey:MonkeyKing = new Monkey();
trace("变鱼后能呆在水里");
var fish:Fish = new Fish(monkey);
fish.change();
fish.water()
/*
变鱼后能呆在水里
this is a monkey
begin change
a fish
he can in water
test2:
*/