【仿真建模-anylogic】Statechart原理解析

news2025/6/9 16:20:14

Author：赵志乾
Date：2024-06-15
Declaration：All Right Reserved！！！

1. 类图

2. 原理解析

2.1 核心函数

Statechart的核心函数如下：

函数	功能
Statechart(Agent owner, short maxat)	构造函数，入参指定状态图owner以及允许的最大激活Transition个数
void start()	启动函数，激活状态图并执行Entry Action
void fireEvent(Object msg)	将消息加入状态图的消息队列,该消息会被立即消费或经过若干个不耗时的执行步后被消费，否则被丢弃
boolean receiveMessage(Object msg)	将消息传递至状态图，要么立即执行，要么被丢弃；

2.2 代码解析

Anylogic内核做了代码混淆，以下代码为二次加工后的逻辑；

//************************核心字段************************
// 状态图所属的Agent    
private transient Agent owner;
// 当前激活的状态
private T activeState = null;
// 当前激活的转换容器
protected Transition[] activeTransitions;
// 当前激活的转换个数
protected int activeTransitionSize = 0;
// 状态图待处理的消息队列
private LinkedList<Object> msgQueue;
// 备份的当前时间
private double currentTime = Double.NEGATIVE_INFINITY;
	
//************************构造函数*************************
// 指定状态图所属的Agent以及状态图允许同时处于激活状态的最大转换数
public Statechart(Agent owner, short maxConcurrentActived) {
    this.owner = owner;
    this.activeTransitions = new Transition[maxConcurrentActived];
    this.activeTransitionSize = 0;
    this.msgQueue = new LinkedList<>();
}

//***********************状态图启动*************************
// 状态图启动函数在owner的start()函数中调用
public void start() {
    // 校验：已启动的状态图不允许再次调用start()
    if (this.activeState != null) {
        this.g.error(this.getFullName() + jj.hdg);
    }
    // 执行自定义逻辑，之后进入首个状态
    this.owner.executeActionOf(this);
}

//************************事件处理**************************
// 无排队:收到事件消息能处理则处理，否则直接丢弃；
public boolean receiveMessage(Object msg) {
    boolean result = false;
    // 遍历当前激活状态的消息转换,并尝试执行转换
    for(int index = 0; index < this.activeTransitionSize ; ++index) {
       Transition transition = this.activeTransitions[index];
       if (transition instanceof TransitionMessage && ((TransitionMessage)transition).f(msg)) {
            //此处仅仅标记结果为成功，并未结束循环；所以当消息匹配多个激活的转换时，这个几个转换将会各自独立执行
            result = true;
        }
     }

     return result;
}

// 有排队:收到事件消息优先进队列,然后尝试消费一次
public void fireEvent(Object msg) {
    double currentTime = this.getAgent().time();
    if (this.currentTime < currentTime) {
        this.msgQueue.clear();
    }

    this.msgQueue.addLast(msg);
    this.currentTime = currentTime;
    this.tryConsume();
}

//*************************转换的激活与取消激活**************************************
// 激活转换:激活转换时,尝试进行一次消费
void activateTransition(Transition transition) {
    this.activeTransition[this.activeTransitionSize++] = transition;
    this.tryConsume();
}
// 取消激活转换
void deactivateTransition(Transition transition) {
    // 找到取消激活的转换所对应的下标
    int index;
    for(index = 0; index< activeTransitionSize; index++){
        if(this.activeTransitions[index] == transition){
			break;
		}
	}
	// 合法性校验：只有激活状态的转换才允许取消激活
	if(index >= this.activeTransitionSize){
		throw new RuntimeException("INTERNAL ERROR: a statechart transition being deactivated is not active");
	}
	// 将之后的元素逐个向前移动
    for(; index<activeTransitionSize-1; index++){
	    this.activeTransitions[index] = this.activeTransitions[index+1];
	}
    // 修正激活转换个数
	this.activeTransitionSize--;
}

//****************************变更*************************************
public void onChange() {
    // 变更发生时,刷新TransitionRate和TransitionCondition的触发条件
    for(int index = 0; index < this.activeTransitionSize; ++index) {
        Transition transition = this.activeTransitions[var1];
        if (transition instanceof TransitionRate) {
            ((TransitionRate)transition).g();
        } else if (transition instanceof TransitionCondition) {
            ((TransitionCondition)transition).g();
        }
    }
}

//*************************尝试消费************************************
private void tryConsume() {
    //清除历史消息
    if (this.getAgent().time() > this.currentTime) {
        this.msgQueue.clear();
        return;
    }
    //尝试消费消息
    int index = 0;
    for(Iterator iterator = this.msgQueue.iterator(); iterator.hasNext(); ++index) {
        Object msg = iterator.next();
        if (this.receiveMessage(msg)) {
            break;
         }
     }
     //消费成功
     if (index < this.msgQueue.size()) {
         //移除成功消费消息及其之前的消息
         for(int cycle = 0; cycle <= index; ++cycle) {
            this.msgQueue.removeFirst();
         }
     }
}