Over a million developers have joined DZone.
{{announcement.body}}
{{announcement.title}}

Groovy Goodness: More Efficient Tail Recursion With TailRecursive Annotation

DZone's Guide to

Groovy Goodness: More Efficient Tail Recursion With TailRecursive Annotation

· Java Zone
Free Resource

Learn how to troubleshoot and diagnose some of the most common performance issues in Java today. Brought to you in partnership with AppDynamics.

Since Groovy 1.8 we can use the trampoline method for a closure to get better recursive behavior for tail recursion. All closure invocations are then invoked sequentially instead of stacked, so there is no StackOverFlowError. As from Groovy 2.3 we can use this for recursive methods as well with the @TailRecursive AST transformation. If we apply the annotation to our method with tail recursion the method invocations will be sequential and not stacked, like with the closure's trampoline method.

import groovy.transform.TailRecursive

@TailRecursive
long sizeOfList(list, counter = 0) {
    if (list.size() == 0) {
        counter
    } else {
       sizeOfList(list.tail(), counter + 1) 
    }
}

// Without @TailRecursive a StackOverFlowError
// is thrown.
assert sizeOfList(1..10000) == 10000

Code written with Groovy 2.3.

Understand the needs and benefits around implementing the right monitoring solution for a growing containerized market. Brought to you in partnership with AppDynamics.

Topics:

Published at DZone with permission of Hubert Klein Ikkink, DZone MVB. See the original article here.

Opinions expressed by DZone contributors are their own.

THE DZONE NEWSLETTER

Dev Resources & Solutions Straight to Your Inbox

Thanks for subscribing!

Awesome! Check your inbox to verify your email so you can start receiving the latest in tech news and resources.

X

{{ parent.title || parent.header.title}}

{{ parent.tldr }}

{{ parent.urlSource.name }}