状态模式

[Musings]
今天继续昨天的内容进行状态模式的书写

public enum StateStatus {
        NORMAL,ALARM,URGENT,SUFFICIENT
}

public class State {
    private StateStatus stateStatus;

    public State(StateStatus stateStatus) {
        this.stateStatus = stateStatus;
    }

    public void handleUpdate(Publisher publisher) {
        /*logic update for status*/
        statusUpdate();
    }

    public void handleReduce(Publisher publisher) {
        /*logic update for status*/
        statusUpdate();
    }

    private void  statusUpdate(){
        /*logic update for status*/
    }
}

public abstract class Publisher {
    private State state;
    /* ...  */

    public Publisher(State state /* ...  */) {
        this.state = state;
    }

    /* 
    ...  
    */
}

public class Storage extends Publisher {

    public Storage(int limit, HashMap storageMap, String name, Mediator mediator) {
        super(new State(StateStatus.NORMAL),limit, storageMap, name, mediator);
        /*如果添加初始化Status的逻辑就在这里加然后调用super*/
    }

    @Override
    public void updateItem(String itemName, int count) {
        this.getStorageMap().computeIfPresent(itemName, (k, v) -> v += count);
        System.out.println(this.getStorageMap().toString());
    }

    @Override
    public void notify(String itemName, int count, State state) {
        // mediator.notify(this, itemName, count);
        mediator.notify(this, this.getState());
        //这里就是核心,传给mediator后,不需要考虑很复杂的业务逻辑,只需要根据state就行
        //说白了就是把之前mediator里的业务逻辑抽出来,放到state里面单独管理,这样就各司其职,mediator类不会过大
    }

    public void add(String itemName, int count) {
        this.getStorageMap().put(itemName, count);
        this.getState().handleUpdate(this);
    }

    public void reduce(String itemName) {
        int currentVal = this.getStorageMap().get(itemName);
        this.getStorageMap().put(itemName, currentVal - 1);
        this.notify(itemName, currentVal - 1);
        this.getState().handleReduce(this);
    }
}

今天就到这,明天继续