Java 8 facilitates several `functional interface`

in `java.util.function`

package. If we observe carefully, there are primarily four kinds of interfaces provided in this package, which are:

- Supplier
- Consumer
- Function
- Predicate

with the following signatures:

Supplier: () -> T
Consumer: T -> ()
Predicate: T -> boolean
Function: T -> R

In this post, alike `java.util.function`

package, we define a new functional interface, called `TriFrunction`

that accepts three arguments as parameters and returns the result after computation.

@FunctionalInterface
public interface TriFunction<T,U,S, R> {
/**
* Applies this function to the given arguments.
*
* @param t the first function argument
* @param u the second function argument
* @param s the third function argument
* @return the function result
*/
R apply(T t, U u, S s);
}

We can use this functional interface to compute the volume of a rectangular prism, by using following `lambda expression`

.

TriFunction volume = (x,y,z) -> x*y*z

To use this lambda expression in the volume computation, we can simply use the following statement

volume.apply(2.4, 5.3, 10.4)

In this post, we have shown how to create a custom `functional interface`

and use it to write concise lambda expressions using Java 8. It seems quite straightforward. If you have any question/remark, please leave a comment below.

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Hi, thank you for the example :) but you are missing type parameters for the interface.

interface TriFunction

Indeed, you are right. I will fix it soon!

Famous last words ;)