前言
装饰者模式是套娃，桥接模式是组合。套娃是外层套娃丢了才能玩，组合是像汽车部件一样缺一不可。
代码说明一切，直接上代码。
装饰者模式
//接口ICake
public interface ICake {
void name();
}
//实现类Cake
public class Cake implements ICake {
@Override
public void name() {
System.out.println("蛋糕");
}
}
//第一个抽象装饰者类SizeCake
public abstract class SizeCake implements ICake {
private ICake cake;
public SizeCake(ICake cake) {
this.cake = cake;
}
@Override
public void name() {
cake.name();
size();
}
public abstract void size();
}
//具体装饰者类BigCake
public class BigCake extends SizeCake {
public BigCake(ICake cake) {
super(cake);
}
@Override
public void size() {
System.out.println("大的");
}
}
//具体装饰者类MiddleCake
public class MiddleCake extends SizeCake {
public MiddleCake(ICake cake) {
super(cake);
}
@Override
public void size() {
System.out.println("中的");
}
}
//具体装饰者类SmallCake
public class SmallCake extends SizeCake {
public SmallCake(ICake cake) {
super(cake);
}
@Override
public void size() {
System.out.println("小的");
}
}
//第一个抽象装饰者类FruitCake
public abstract class FruitCake implements ICake {
private ICake cake;
public FruitCake(ICake cake) {
this.cake = cake;
}
@Override
public void name() {
cake.name();
fruit();
}
public abstract void fruit();
}
//具体装饰者类AppleCake
public class AppleCake extends FruitCake {
public AppleCake(ICake cake) {
super(cake);
}
@Override
public void fruit() {
System.out.println("苹果");
}
}
//具体装饰者类PearCake
public class PearCake extends FruitCake {
public PearCake(ICake cake) {
super(cake);
}
@Override
public void fruit() {
System.out.println("梨");
}
}
//具体装饰者类StrawberryCake
public class StrawberryCake extends FruitCake {
public StrawberryCake(ICake cake) {
super(cake);
}
@Override
public void fruit() {
System.out.println("草莓");
}
}
//客户端测试代码
public static void main(String[] args) {
Cake cake = new Cake();
BigCake bigCake = new BigCake(cake);
AppleCake appleCake = new AppleCake(bigCake);
appleCake.name();
}
桥接模式
//抽象父Cake
public abstract class Cake {
private IFruit fruit;
public void name() {
System.out.println("蛋糕");
size();
if (null != fruit) {
fruit.name();
}
}
public abstract void size();
public void setFruit(IFruit fruit) {
this.fruit = fruit;
}
}
//子类BigCake
public class BigCake extends Cake {
@Override
public void size() {
System.out.println("大的");
}
}
//子类MiddleCake
public class MiddleCake extends Cake {
@Override
public void size() {
System.out.println("中的");
}
}
//子类SmallCake
public class SmallCake extends Cake {
@Override
public void size() {
System.out.println("小的");
}
}
//接口IFruit
public interface IFruit {
void name();
}
//实现接口IFruit的类Apple
public class Apple implements IFruit {
@Override
public void name() {
System.out.println("苹果");
}
}
//实现接口IFruit的类Pear
public class Pear implements IFruit {
@Override
public void name() {
System.out.println("梨");
}
}
//实现接口IFruit的类Strawberry
public class Strawberry implements IFruit {
@Override
public void name() {
System.out.println("草莓");
}
}
public static void main(String[] args) {
BigCake cake = new BigCake();
cake.setFruit(new Apple());
cake.name();
}
结果
总结
以上面代码为例，
1、对于装饰者模式，在蛋糕的基础上，可以添加大小、水果等作为装饰。这些装饰可以加可以不加。
2、对于桥接模式，蛋糕的属性中就有大小和水果，所以这两者都必须有的，才能生成一个蛋糕。
显然，桥接模式的耦合度要更大一些，它是一种组合关系。
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