func (this *RepeatUntilSuccess) Initialize(setting *BTNodeCfg) {
	this.Decorator.Initialize(setting)
	this.maxLoop = setting.GetPropertyAsInt("maxLoop")
	if this.maxLoop < 1 {
		panic("maxLoop parameter in MaxTime decorator is an obligatory parameter")
	}
}

func (this *BehaviorTree) Tick(target interface{}, blackboard *Blackboard) b3.Status {
	if blackboard == nil {
		panic("The blackboard parameter is obligatory and must be an instance of b3.Blackboard")
	}

	/* CREATE A TICK OBJECT */
	var tick = NewTick() //每次tick即调用一次NewTick()
	tick.debug = this.debug
	tick.target = target
	tick.Blackboard = blackboard
	tick.tree = this

	/* TICK NODE */
	var state = this.root._execute(tick)

	/* CLOSE NODES FROM LAST TICK, IF NEEDED */
	var lastOpenNodes = blackboard._getTreeData(this.id).OpenNodes
	var currOpenNodes []IBaseNode
	currOpenNodes = append(currOpenNodes, tick._openNodes...)

	// does not close if it is still open in this tick
	var start = 0
	for i := 0; i < b3.MinInt(len(lastOpenNodes), len(currOpenNodes)); i++ {
		start = i + 1
		if lastOpenNodes[i] != currOpenNodes[i] {
			break
		}
	}

	// close the nodes
	for i := len(lastOpenNodes) - 1; i >= start; i-- {
		lastOpenNodes[i]._close(tick)
	}

	/* POPULATE BLACKBOARD */
	blackboard._getTreeData(this.id).OpenNodes = currOpenNodes
	blackboard.SetTree("nodeCount", tick._nodeCount, this.id)

	return state
}

func NewTick() *Tick {
	tick := &Tick{} //此处建议用pool
	tick.Initialize()
	return tick
}