public ProcessNode getProcessNodeById(String nodeId){
		if(nodeId==null)
			return null;
		ProcessNode pn = null;
		if(nodeId.equals(this.getBeginNode().getProcessNodeId()))
			pn =  this.getBeginNode();
		if(pn==null)
			pn=this.procedureNodes.get(nodeId);
		if(pn==null){
			if(nodeId.equals(this.getEndNode().getProcessNodeId()))
				pn =  this.getEndNode();
		}
		return pn;
		
	}