code: public HppRequest generateDefaults(String secret) {
  
  		//generate timestamp if not set
  		if (null == this.timeStamp || "".equals(this.timeStamp)) {
  			this.timeStamp = GenerationUtils.generateTimestamp();
  		}
  
  		//generate order ID if not set
  		if (null == this.orderId || "".equals(this.orderId)) {
  			this.orderId = GenerationUtils.generateOrderId();
  		}
  
  		//generate hash
  		hash(secret);
  
  		return this;
  	}
docs: Generates default values for fields such as hash, timestamp and order ID.
  
  @param secret
  @return HppRequest