装饰器模式(Decorator Pattern)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。这种类型的设计模式属于结构型模式,它是作为现有的类的一个包装。
这种模式创建了一个装饰类,用来包装原有的类,并在保持类方法签名完整性的前提下,提供了额外的功能。
装饰模式为已有类动态附加额外的功能就像LOL、王者荣耀等类Dota游戏中,英雄升级一样。每次英雄升级都会附加一个额外技能点学习技能。具体的英雄就是ConcreteComponent,技能栏就是装饰器Decorator,每个技能就是ConcreteDecorator;//Component 英雄接口 public interface Hero { //学习技能 void learnSkills(); } //ConcreteComponent 具体英雄盲僧 public class BlindMonk implements Hero { private String name; public BlindMonk(String name) { this.name = name; } @Override public void learnSkills() { System.out.println(name + "学习了以上技能!"); } } //Decorator 技能栏 public class Skills implements Hero{ //持有一个英雄对象接口 private Hero hero; public Skills(Hero hero) { this.hero = hero; } @Override public void learnSkills() { if(hero != null) hero.learnSkills(); } } //ConreteDecorator 技能:Q public class Skill_Q extends Skills{ private String skillName; public Skill_Q(Hero hero,String skillName) { super(hero); this.skillName = skillName; } @Override public void learnSkills() { System.out.println("学习了技能Q:" +skillName); super.learnSkills(); } } //ConreteDecorator 技能:W public class Skill_W extends Skills{ private String skillName; public Skill_W(Hero hero,String skillName) { super(hero); this.skillName = skillName; } @Override public void learnSkills() { System.out.println("学习了技能W:" + skillName); super.learnSkills(); } } //ConreteDecorator 技能:E public class Skill_E extends Skills{ private String skillName; public Skill_E(Hero hero,String skillName) { super(hero); this.skillName = skillName; } @Override public void learnSkills() { System.out.println("学习了技能E:"+skillName); super.learnSkills(); } } //ConreteDecorator 技能:R public class Skill_R extends Skills{ private String skillName; public Skill_R(Hero hero,String skillName) { super(hero); this.skillName = skillName; } @Override public void learnSkills() { System.out.println("学习了技能R:" +skillName ); super.learnSkills(); } } //客户端:召唤师 public class Player { public static void main(String[] args) { //选择英雄 Hero hero = new BlindMonk("李青"); Skills skills = new Skills(hero); Skills r = new Skill_R(skills,"猛龙摆尾"); Skills e = new Skill_E(r,"天雷破/摧筋断骨"); Skills w = new Skill_W(e,"金钟罩/铁布衫"); Skills q = new Skill_Q(w,"天音波/回音击"); //学习技能 q.learnSkills(); } }输出:
学习了技能Q:天音波/回音击 学习了技能W:金钟罩/铁布衫 学习了技能E:天雷破/摧筋断骨 学习了技能R:猛龙摆尾 李青学习了以上技能!
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