Java 设计模式系列(14) —— 享元模式

public abstract class Flyweight {
    private String innerState;
    protected final String extrernalState;
    public Flyweight(String externalState) {
        this.extrernalState = externalState;
    }
    
    public abstract void operation();
    
    public String getInnerState() {
        return this.getInnerState();
    }
    
    public void setInnerState(String innerState) {
        this.innerState = innerState;
    }
}

public class ConcreteFlyweight extends Flyweight{
    public ConcreteFlyweight(String externalState) {
        super(externalState);
        // TODO Auto-generated constructor stub
    }
    @Override
    public void operation() {
        // TODO Auto-generated method stub
        
    }
}

public class FlyweightFactory {
    private static HashMap<String,Flyweight> pool = new HashMap();
    public static Flyweight getFlyweight(String external) {
        Flyweight fly = null;
        if(pool.containsKey(external)) {
            fly =  pool.get(external);
        }else {
            fly = new ConcreteFlyweight(external);
            pool.putIfAbsent(external, fly);
        }
        return fly;
    }
}