构造器模式

意图
- 将一个复杂对象的构建和表示分离，使得相同的构建能创建不同的表示。
解释

案例：想象一个角色扮演游戏的特征生成器。最简单的选择是让计算机为你创建角色。如果你想手动选择特征的细节像职业、性别、头发的颜色等。特征的产生是一个循序渐进的过程，当所有选择都就绪时结束。

简单说：允许你在避免函数污染的情况下创建不同特征的对象。当一个对象有好几种特征时或当创建对象需要很多步骤时。

样例

//盔甲
public enum Armor {CHAIN_MAIL("Chain Mail"),CLOTHES("Clothes"),LEATHER("leather"),PLATE("plate");private String description;Armor(String description) {this.description = description;}public String getDescription() {return description;}
}

//头发的颜色
public enum HairColor {BLACK,BLOND,BROWN,RED,WHITE;
}

//头发类型
public enum HairType {BALD("bald"),CURLY("curly"),LONG_CURLY("long curly"),LONG_STRAIGHT("long straight"),SHORT("short");private String description;HairType(String description) {this.description = description;}
}

//职业
public enum Profession {MAGE,PRIEST,THIEF,WARRIOR;
}

//武器
public enum Weapon {AXE,BOW,DAGGER,SWORD,WARHAMMER;}

//角色
public final class Hero {private Armor armor;private Weapon weapon;private HairType hairType;private HairColor hairColor;private Profession profession;public Hero(Builder builder){this.armor = builder.armor;this.weapon = builder.weapon;this.hairType = builder.hairType;this.hairColor = builder.hairColor;this.profession = builder.profession;}public Armor getArmor() {return armor;}public Weapon getWeapon() {return weapon;}public HairType getHairType() {return hairType;}public HairColor getHairColor() {return hairColor;}public Profession getProfession() {return profession;}public static class Builder {private Armor armor;private HairType hairType;private HairColor hairColor;private Profession profession;private Weapon weapon;private String name;public Builder(Profession profession, String name) {this.profession = profession;this.name = name;}public Hero build() {return new Hero(this);}Builder withArmor(Armor armor) {this.armor = armor;return this;}Builder withHairType(HairType hairType) {this.hairType = hairType;return this;}Builder withHairColor(HairColor hairColor) {this.hairColor = hairColor;return this;}Builder withWeapon(Weapon weapon) {this.weapon = weapon;return this;}}}

public class Main {public static void main(String[] args) {var riobard = new Hero.Builder(Profession.MAGE, "Riobard").withHairColor(HairColor.BLACK).withWeapon(Weapon.DAGGER).build();}
}