Is there a way to pass Java code sniplet as Groovy Closure in method param?

Question

I am currently translating legacy groovy class with methods to Java, and for most methods it has been easy with slight modifications. Now I am stuck in a method that takes closure as param:

transformer.renameNumbers([:], { Number->
        return "${number.name}@somecompany.com"
    })
}

the renameNumbers implementation is :

renameNumbers(Map<String,String> renameMap, someclosure = {it}) {
    numbers.each { it->

        if(newUsername == null ) {
            newNumbername = someclosure.call(it)
        }
        if(newNumbername!=null && newNumbername!=it.number) {
            def oldNumber= it.number
            it.number = newNumbername

            log.info("Changed numbername key of  from '$oldNumber' to '$newNumbername'")
        }
    }

The problem is that if i try to simply pass: transformer.renameNumbers(Map, Object)

it complains:

groovy.lang.MissingMethodException: No signature of method: org.eclipse.emf.ecore.util.EObjectContainmen.call() is applicable for argument types:

I guess it's because my normal Java Object doesn't have call() methods. Is there a way to circumvent this? For example if I create custom Java class with custom call method ?

Thanks

To prevent confusion, be aware, that there's already a `Number` class in Java: https://docs.oracle.com/javase/7/docs/api/java/lang/Number.html — Markus Mitterauer, Mar 15 '19 at 15:10
Possible duplicate of [Java Pass Method as Parameter](https://stackoverflow.com/questions/2186931/java-pass-method-as-parameter) — Markus Mitterauer, Mar 15 '19 at 15:14

score 0 · Answer 1 · answered Mar 15 '19 at 15:05

You could try using Java 8s functional interfaces like Function<T,R> and Lambdas:

//Function<Number, String> f = (n) -> n.name + "@somecompany.com";
transformer.renameNumbers(new HashMap<>(), (n) -> n.name + "@somecompany.com");

Usage :

void renameNumbers(Map<String, String> renameMap, Function<Number, String> somefunction) {
    numbers.forEach(it -> {
        String newNumbername = somefunction.apply(it); // <-----
        if (newNumbername != null && newNumbername != it.number) {
            String oldNumber = it.number; 
            it.number = newNumbername;
            log.info("Changed numbername key of  from '" + oldNumber + "' to '" + newNumbername + "'");
        }
    });
}

Is there a way to pass Java code sniplet as Groovy Closure in method param?

1 Answers1