func (c *AssetMgr) Invoke(stub shim.ChaincodeStubInterface) pb.Response {
               function, args := stub.GetFunctionAndParameters()
               if function == "Order" {
                               return c.Order(stub, args)
               } else if function == "Ship" {
                               return c.Ship(stub, args)
               } else if function == "Distribute" {
                               return c.Distribute(stub, args)
               } else if function == "query" {
                               return c.query(stub, args)
               } else if function == "getHistory" {
                               return c.getHistory(stub, args)
               }
               return shim.Error("Invalid function name")
}

func (c *AssetMgr) UpdateAsset(stub shim.ChaincodeStubInterface, args []string, currentStatus string, from string, to string) pb.Response {
               assetId := args[0]   comment := args[1]               location := args[2]
               assetBytes, err := stub.GetState(assetId)
               orgAsset := OrgAsset{}
               …
               if currentStatus == "ORDER" && orgAsset.Status != "START" {
               return shim.Error(err.Error())
               } else if currentStatus == "SHIP" && orgAsset.Status != "ORDER" {.}
else if currentStatus == "DISTRIBUTE" && orgAsset.Status != "SHIP" {.}
               orgAsset.Comment = comment
               orgAsset.Status = currentStatus
….
               orgAsset0, _ := json.Marshal(orgAsset)
               err = stub.PutState(assetId, orgAsset0)
               …
               return shim.Success(orgAsset0)
}