享元模式
享元模式（Flyweight Pattern）运用共享技术有效地支持大量细粒度对象的复用。
示意图
示例代码
ts
interface Flyweight {
operation(): void;
}
class ConcreteFlyweight implements Flyweight {
operation(): void {}
}
class FlyweightFactory {
private flyweights: Map<string, Flyweight> = new Map();
getFlyweight(key: string): Flyweight {
if (!this.flyweights.has(key)) {
const flyweight = new ConcreteFlyweight();
this.flyweights.set(key, flyweight);
}
return this.flyweights.get(key)!;
}
}interface Flyweight {
operation(): void;
}
class ConcreteFlyweight implements Flyweight {
operation(): void {}
}
class FlyweightFactory {
private flyweights: Map<string, Flyweight> = new Map();
getFlyweight(key: string): Flyweight {
if (!this.flyweights.has(key)) {
const flyweight = new ConcreteFlyweight();
this.flyweights.set(key, flyweight);
}
return this.flyweights.get(key)!;
}
}优缺点
优点
- 大大减少对象的创建，降低内存的占用情况。
缺点
- 提高了系统的复杂度，需要分离出外部状态和内部状态。
使用场景
- 系统中有大量相同或者相似的对象，由于这类对象的大量使用，造成内存的大量耗费。