相关文章
【合集】Java设计模式
装饰者模式
其实就是继承抽象构件，又组合了一个抽象构件
抽象构件-饮品
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@Getter
@AllArgsConstructor
public abstract static class Drink {
private String des;
private float price;
public abstract float cost();
}
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抽象构件-饮品（继承饮品）
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public static class Coffee extends Drink {
public Coffee(String des, float price) {
super(des, price);
}
@Override
public float cost() {
return super.price;
}
}
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具体构件-美式咖啡
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public static class LongBlack extends Coffee {
public LongBlack() {
super("longBlack", 5.0f);
}
}
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具体构件-意大利咖啡
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public static class Espresso extends Coffee {
public Espresso() {
super("意大利咖啡", 6.0f);
}
}
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装饰抽象类
其实就是继承抽象构件，又组合了一个抽象构件
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public static class Decorator extends Drink {
private final Drink obj;
public Decorator(Drink obj, String des, float price) {
super(des, price);
this.obj = obj;
}
@Override
public float cost() {
return super.price + obj.cost();
}
@Override
public String getDes() {
return super.des + obj.getDes();
}
}
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具体装饰类-巧克力
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public static class Chocolate extends Decorator {
public Chocolate(Drink obj) {
super(obj, "巧克力", 3.0f);
}
}
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具体装饰类-牛奶
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public static class Milk extends Decorator {
public Milk(Drink obj) {
super(obj, "牛奶", 2.0f);
}
}
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具体装饰类-豆浆
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public static class Soy extends Decorator {
public Soy(Drink obj) {
super(obj, "豆浆", 1.5f);
}
}
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客户端调用
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Drink order = new LongBlack();
order = new Milk(order);
System.out.println(order.getDes() + " " + order.cost() + "元");
order = new Chocolate(order);
System.out.println(order.getDes() + " " + order.cost() + "元");
order = new Chocolate(order);
System.out.println(order.getDes() + " " + order.cost() + "元");
System.out.println("===========================");
Drink order2 = new Soy(order);
System.out.println(order2.getDes() + " " + order2.cost() + "元");
order2 = new Milk(order2);
System.out.println(order2.getDes() + " " + order2.cost() + "元");
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输出
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牛奶longBlack 7.0元
巧克力牛奶longBlack 10.0元
巧克力巧克力牛奶longBlack 13.0元
===========================
豆浆巧克力巧克力牛奶longBlack 14.5元
牛奶豆浆巧克力巧克力牛奶longBlack 16.5元
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应用
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应用：{@link java.io.FilterInputStream}装饰角色就是继承了InputStream, 并且组合了InputStream, {@link java.io.BufferedInputStream}则是具体装饰角色
应用：{@link java.io.InputStreamReader}装饰角色就是继承了Reader, 并且组合了StreamDecoder，{@link java.io.FileReader}则是具体装饰角色
应用：{@link java.io.BufferedReader}装饰角色就是继承了Reader, 并且组合了Reader
应用：{@link java.io.OutputStreamWriter}装饰角色就是继承了Writer, 并且组合了StreamEncoder，{@link java.io.FileWriter}则是具体装饰角色
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文件输入流
装饰角色：java.io.FilterInputStream
被装饰的接口：InputStream
