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Java 8 - Functions - Currying





  • Sometimes, all inputs to a function are not available at the time of function application.
  • Thus, we can apply only the available inputs, and then return a function which can be applied to the remaining inputs, whenever those remaining inputs are available.
  • A curried function is one which can accept partial inputs.
  • Currying is the process of making an un-curried function curried.

@Slf4j
public class Currying {

   static BiFunction<String, String, String> uncurried = (a, b) -> "Hello " + a + b;

   static Function<String, Function<String, String>> curried = a -> (b -> "Hello " + a + b);

   public static void main(String[] args) {
     log.info("uncurried function output: " + uncurried.apply("Tom", "Cruise"));

     Function<String, String> partiallyAppliedFunction = curried.apply("Tom");

     log.info("finally, curried function output: " + partiallyAppliedFunction.apply("Cruise"));
   }
}
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