Copy Groovy class properties

Question

I want to copy object properties to another object in a generic way (if a property exists on target object, I copy it from the source object).

My co

Answer 1

I think your solution is quite good and is in the right track. At least I find it quite understandable.

A more succint version of that solution could be...

def copyProperties(source, target) {
    source.properties.each { key, value ->
        if (target.hasProperty(key) && !(key in ['class', 'metaClass'])) 
            target[key] = value
    }
}

... but it's not fundamentally different. I'm iterating over the source properties so I can then use the values to assign to the target :). It may be less robust than your original solution though, as I think it would break if the target object defines a getAt(String) method.

If you want to get fancy, you might do something like this:

def copyProperties(source, target) {
    def (sProps, tProps) = [source, target]*.properties*.keySet()
    def commonProps = sProps.intersect(tProps) - ['class', 'metaClass']
    commonProps.each { target[it] = source[it] }
}

Basically, it first computes the common properties between the two objects and then copies them. It also works, but I think the first one is more straightforward and easier to understand :)

Sometimes less is more.