CODEWITHSUNDEEP
groovyif-statement
Matthew Brown
Matthew Brown

Reputation: 1052

Test only if variable is not null in if statement

I have the following method where I want to test the event.status property only if status has been passed in: 

def findEvent(String desc, String status = null, Collection events) {
        return events.find {
            it.description == desc && \\If status is not null: it.status == status
        }

        throw new Exception("Review Event Record Not Found: ${desc}")
}

I thought it could be done like this, but it doesn't seem to work:

def findEvent(String desc, String status = null, Collection events) {
        return events.find {
            it.description == desc && (status != null ?: {it.status == status})
        }

        throw new Exception("Review Event Record Not Found: ${desc}")
}

Is there any way this could be done? Or do I have to go back to something like this:

if (status != null) {
    return events.find {
        it.description == desc && it.status == status
    }
} else if (status == null) {
    return events.find {
        it.description == desc
    }
}

Is there some kind of best practice?

Upvotes: 19

Views: 113692

Answers (1)

Dave Newton
Dave Newton

Reputation: 160191

I don't believe the expression is sensical as it is.

Elvis means "if truthy, use the value, else use this other thing."

Your "other thing" is a closure, and the value is status != null, neither of which would seem to be what you want. If status is null, Elvis says true. If it's not, you get an extra layer of closure.

Why can't you just use:

(it.description == desc) && ((status == null) || (it.status == status))

Even if that didn't work, all you need is the closure to return the appropriate value, right? There's no need to create two separate find calls, just use an intermediate variable.

Upvotes: 22

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