设计模式(13):JAVA(13):设计模式（6）装饰器模式：允许向一个现有的对象添加新的功能,同时又不改变其结构
作者：互联网
例1
package com.woniuxy.m_decorator.a;
/*
星巴克是卖咖啡的， 一开始饮料种类比较少，所以使用继承，看不出什么问题。
每种咖啡，都有描述，都有价格。 这是所有咖啡的共性，既然是共性，就要上提到父类中。
*/
abstract class Beverage {
private String description;
public Beverage(String description) {
super();
this.description = description;
}
public abstract double cost();
}
class DarkRoast extends Beverage {
public DarkRoast(String descriptoin) {
super(descriptoin);
}
public double cost() {
return 10;
}
}
class Decaf extends Beverage {
public Decaf(String description) {
super(description);
}
@Override
public double cost() {
return 8;
}
}
class Espresso extends Beverage {
public Espresso(String description) {
super(description);
}
@Override
public double cost() {
return 12;
}
}
class HouseBlend extends Beverage {
public HouseBlend(String description) {
super(description);
}
@Override
public double cost() {
return 15;
}
}
public class Test {
}
例2
星巴克，业务壮大了，为了把同业抛开，它加了新的花样： 4种调料：
蒸奶（steamed Milk）、豆浆（Soy）、摩卡（Mocha）、打起奶泡（Whip）
针对于DrakRoast咖啡，可以有以下几种变化：
DrakRoast
DrakRoastWithSteamedMilk
DrakRoastWithSoy
DrakRoastWithMocha
DrakRoastWithWhip
DrakRoastWithSteamedMilkAndSoy
.....
类，爆炸了！！ 程序员，疯了！！
例3
package com.woniuxy.m_decorator.c;
// 为了解决b包的问题，
// 作者，尝试这样来解决：
// 优点，没有类爆炸！
class Beverage {
private String description;
private boolean steamedMilk;
private boolean soy;
private boolean mocha;
private boolean whip;
public Beverage(String description) {
super();
this.description = description;
}
public double cost() {
double cost = 0;
if(steamedMilk) {
cost += 0.2;
}
if(soy) {
cost += 0.2;
}
if(mocha) {
cost += 0.3;
}
if(whip) {
cost += 0.1;
}
return cost;
}
/*
public double cost(Map map) {
double cost = 0;
for(Entry e : map.entrySet() ) {
cost += e.getValue();
}
return cost;
}
public String description(Map map) {
String str = 0;
for(Entry e : map.entrySet() ) {
str += e.getKey() + " ";
}
return str;
}
Map map = new HashMap();
map.put("Milk", 0.2);
map.put("Soy", 0.2);
map.put("Whip", 0.1);
map.put("GouqI", 0.1);
cost(map);
getDescription(map);
*/
public boolean isSteamedMilk() {
return steamedMilk;
}
public void setSteamedMilk(boolean steamedMilk) {
this.steamedMilk = steamedMilk;
}
public boolean isSoy() {
return soy;
}
public void setSoy(boolean soy) {
this.soy = soy;
}
public boolean isMocha() {
return mocha;
}
public void setMocha(boolean mocha) {
this.mocha = mocha;
}
public boolean isWhip() {
return whip;
}
public void setWhip(boolean whip) {
this.whip = whip;
}
}
class DarkRoast extends Beverage {
public DarkRoast(String descriptoin) {
super(descriptoin);
}
public double cost() {
return super.cost() + 10;
}
/*
public String getDescription(Map map) {
return descriptoin + super.getDesciption(Map map);
}
*/
}
class Decaf extends Beverage {
public Decaf(String description) {
super(description);
}
@Override
public double cost() {
return super.cost() + 8;
}
}
class Espresso extends Beverage {
public Espresso(String description) {
super(description);
}
@Override
public double cost() {
return super.cost() + 12;
}
}
class HouseBlend extends Beverage {
public HouseBlend(String description) {
super(description);
}
@Override
public double cost() {
return super.cost() + 15;
}
}
// =========================================================
class Tea extends Beverage {
public Tea(String description) {
super(description);
}
public double cost() {
return super.cost() + 9;
}
}
public class Test {
public static void main(String[] args) {
DarkRoast dr = new DarkRoast("焦炒咖啡");
dr.setMocha(true);
dr.setSoy(true);
System.out.println(dr.cost());
HouseBlend hb = new HouseBlend("混合咖啡");
hb.setWhip(true);
System.out.println(hb.cost());
Tea tea = new Tea("凉茶");
tea.setSoy(true);
System.out.println(tea.cost());
}
}
// 缺点：
// 现在多了一个调料：枸杞。
例4
package com.woniuxy.m_decorator.d;
import java.io.IOException;
// 为了解决c包的问题，
abstract class Beverage {
private String description;
public Beverage(String description) {
super();
this.description = description;
}
public abstract double cost();
public String getDescription() {
return description;
}
}
class DarkRoast extends Beverage {
public DarkRoast(String descriptoin) {
super(descriptoin);
}
public double cost() {
return 10;
}
}
class Decaf extends Beverage {
public Decaf(String description) {
super(description);
}
@Override
public double cost() {
return 8;
}
}
class Espresso extends Beverage {
public Espresso(String description) {
super(description);
}
@Override
public double cost() {
return 12;
}
}
class HouseBlend extends Beverage {
public HouseBlend(String description) {
super(description);
}
@Override
public double cost() {
return 15;
}
}
abstract class CondimentDecorator extends Beverage {
public CondimentDecorator() {
super("调料");
}
public abstract double cost();
}
class Milk extends CondimentDecorator {
private Beverage beverage;
public Milk(Beverage beverage) {
this.beverage = beverage;
}
@Override
public double cost() {
return beverage.cost() + 0.2;
}
@Override
public String getDescription() {
return beverage.getDescription() + " 牛奶";
}
}
class Mocha extends CondimentDecorator{
private Beverage beverage;
public Mocha(Beverage beverage) {
this.beverage = beverage;
}
@Override
public double cost() {
return beverage.cost() + 0.3;
}
@Override
public String getDescription() {
return beverage.getDescription() + " 摩卡";
}
}
class Soy extends CondimentDecorator {
private Beverage beverage;
public Soy(Beverage beverage) {
this.beverage = beverage;
}
@Override
public double cost() {
return beverage.cost() + 0.2;
}
@Override
public String getDescription() {
return beverage.getDescription() + " 豆浆";
}
}
class Whip extends CondimentDecorator {
private Beverage beverage;
public Whip(Beverage beverage) {
this.beverage = beverage;
}
@Override
public double cost() {
return beverage.cost() + 0.1;
}
@Override
public String getDescription() {
return beverage.getDescription() + " 奶泡";
}
}
// =========================================================
class GouQi extends CondimentDecorator {
private Beverage beverage;
public GouQi(Beverage beverage) {
super();
this.beverage = beverage;
}
@Override
public String getDescription() {
return beverage.getDescription() + " 枸杞";
}
@Override
public double cost() {
return beverage.cost() + 0.4;
}
}
public class Test {
public static void main(String[] args) throws IOException {
Beverage b = new DarkRoast("焦炒咖啡");
Beverage b2 = new Milk(b);
Beverage b3 = new Soy(b2);
Beverage b4 = new Whip(b3);
Beverage b5 = new Milk(b4);
Beverage b6 = new GouQi(b5);
System.out.println(b6.getDescription() + ":" + b6.cost());
}
}
例5
package com.woniuxy.m_decorator.e;
import java.io.FileReader;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
// 根据已有功能，做出更强大的功能！
class MyBufferedReader extends FilterReader {
private Reader in;
protected MyBufferedReader(Reader in) {
super(in);
this.in = in;
}
public String readLine() throws IOException {
StringBuilder sb = new StringBuilder("");
int n = 0;
while((n = in.read()) != -1) {
if(n == '\r' ) {
continue;
}
if(n == '\n' ) {
break;
}
sb.append((char)n);
}
// 流程能走到这里，n有几种可能？ 一个是-1, 是\n
return n == -1 ? null: sb.toString();
}
@Override
public void close() throws IOException {
in.close();
}
}
public class Test {
public static void main(String[] args) throws Exception {
Reader in = new FileReader("F:\\1.txt");
MyBufferedReader mbr = new MyBufferedReader(in);
String line = null;
while((line = mbr.readLine()) != null) {
System.out.println(line);
}
mbr.close();
}
}
标签：13,JAVA,description,String,Beverage,return,设计模式,public,cost 来源： https://www.cnblogs.com/qiu-hua/p/15227406.html