如何用地图替换多个“ if-else-if”

Question

I am getting one concern on multi layer if-else-if condition so I want to make short by using a map.

Please see below code in if-else-if which I want to replace with a map.

function, args := APIstub.GetFunctionAndParameters()

if function == "queryProduce" {
    return s.queryProduce(APIstub, args)
} else if function == "initLedger" {
    return s.initLedger(APIstub)
} else if function == "createProduce" {
    return s.createProduce(APIstub, args)
} else if function == "queryAllProduces" {
    return s.queryAllProduces(APIstub)
} else if function == "changeProduceStatus" {
    return s.changeProduceStatus(APIstub, args)
}

return shim.Error("Invalid Smart Contract function name.")
}

Answer 1

For what you have a switch would be nice:

switch function {
case "queryProduce":
    return s.queryProduce(APIstub, args)
case "initLedger":
    return s.initLedger(APIstub)
case "createProduce":
    return s.createProduce(APIstub, args)
case "queryAllProduces":
    return s.queryAllProduces(APIstub)
case "changeProduceStatus":
    return s.changeProduceStatus(APIstub, args)
}

Using a map would be inconvenient because not all your methods have the same signature, but you could use multiple maps.

Yet another solution could be to use reflection to call the methods, but again, handling the different arguments would be inconvenient. Reflection is also slower, not to mention you'd have to take care of not to allow calling methods not intended to be exposed. For an example, see Call functions with special prefix/suffix.