例子一、咖啡的制作
/**
* 饮料类
*/
public abstract class Beverage {
//描述
String description = "Unknown Beverage";
public String getDescription(){
return description;
}
//价格
public abstract double cost();
}
/**
* 调料类
*/
public abstract class CondimentDecorator extends Beverage{
//所有的调料装饰者都必须重新实现该方法
public abstract String getDescription();
}
/**
* 浓咖啡,是一种饮料
*/
public class Espresso extends Beverage{
public Espresso(){
description = "Espresso";
}
@Override
public double cost() {
return 1.99;
}
}
/**
* 混合咖啡
*/
public class HouseBlend extends Beverage{
public HouseBlend(){
description = "House Blend Coffee";
}
@Override
public double cost() {
return 0.89;
}
}
/**
* 摩卡,一种调料
*/
public class Mocha extends CondimentDecorator{
Beverage beverage;
public Mocha(Beverage beverage){
this.beverage = beverage;
}
@Override
public String getDescription() {
return beverage.getDescription() + ",Mocha";
}
@Override
public double cost() {
return 0.20 + beverage.cost();
}
}
/**
* 星巴克咖啡的制作
*/
public class StarbuzzCoffee {
public static void main(String[] args) {
Beverage beverage1 = new Espresso();//浓咖啡,不需要调料
System.out.println(beverage1.getDescription() + " $" + beverage1.cost());
Beverage beverage2 = new HouseBlend();//混合咖啡,需要调料
beverage2 = new Mocha(beverage2);
System.out.println(beverage2.getDescription() + " $" + beverage2.cost());
}
/**
* 运行结果:
* Espresso $1.99
House Blend Coffee,Mocha $1.09
*/
}
例子二、io流的装饰
import java.io.FilterInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* 编写自己的java IO装饰者
* 把流内的所有大写字符转成小写
* FilterInputStream 包含其他一些输入流，它将这些流用作其基本数据源，
* 它可以直接传输数据或提供一些额外的功能。FilterInputStream 类本身只
* 是简单地重写那些将所有请求传递给所包含输入流的 InputStream 的所有方法。
*/
public class LowerCaseInputStream extends FilterInputStream{
/**
* @param in
*/
protected LowerCaseInputStream(InputStream in) {
super(in);
}
//重写,转化为小写
@Override
public int read() throws IOException {
int c = super.read();
return (c == -1 ? c : Character.toLowerCase((char)c));
}
//重写,转化为小写
@Override
public int read(byte[] b, int off, int len) throws IOException {
int result = super.read(b, off, len);
for(int i = off; i < off + result; i++){
b[i] = (byte)Character.toLowerCase((char)b[i]);
}
return result;
}
}
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
/**
* 测试java IO装饰者
*/
public class TestLowerCaseInStr {
public static void main(String[] args) throws IOException {
int c;
InputStream in = new LowerCaseInputStream(new BufferedInputStream(new FileInputStream("C:\\Format.txt")));
while((c = in.read()) >= 0){
System.out.println((char)c);
}
in.close();
}
}