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Groovy best/recommended approach to ensure correct argument type

I'm trying to do things in the best "Groovy-way" possible. What's the best way to check the type of an argument (regarding performance and the "Groovy-way)? I have 2 implementations in mind:

def deploy(json) {
    if (!(json instanceof String) && (json instanceof File)) {
        json = json.text
    } else {
        throw new IllegalArgumentException('argument type mismatch – \'json\' should be String or File')
    }
    // TODO
}

or 

def deploy(File json) {
    deploy(json.text)
}

def deploy(String json) {
    // TODO
}

Thanks :)

Solution

  • There's nothing groovy specific in your question, it's more about compile/runtime failures.

    In first snippet json variable has Object type and allows everything to be passed in. It will fail in runtime if you pass in JSON object or Map by mistake.

    In second snippet json is restricted to be either File or String. I like it more.