Groovy example source code file (TrampolineTest.groovy)

This example Groovy source code file (TrampolineTest.groovy) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - Groovy tags/keywords

biginteger, biginteger, groovytestcase, groovytestcase, trampolinetest, trampolinetest

The Groovy TrampolineTest.groovy source code

package org.codehaus.groovy.runtime.trampoline

/**
 * Test for the trampoline capabilities of closures.
 *
 * @author Vaclav Pech
 */
class TrampolineTest extends GroovyTestCase {
    public void testFactorial() {
        def fact
        fact = { int n, BigInteger accumulator ->
            n > 1 ? fact.trampoline(n - 1, n * accumulator) : accumulator
        }.trampoline()
        def factorial = {int n -> fact(n, 1 as BigInteger)}
        assert factorial(1)    == 1
        assert factorial(2)    == 2
        assert factorial(3)    == 6
        assert factorial(1000) == 402387260077093773543702433923003985719374864210714632543799910429938512398629020592044208486969404800479988610197196058631666872994808558901323829669944590997424504087073759918823627727188732519779505950995276120874975462497043601418278094646496291056393887437886487337119181045825783647849977012476632889835955735432513185323958463075557409114262417474349347553428646576611667797396668820291207379143853719588249808126867838374559731746136085379534524221586593201928090878297308431392844403281231558611036976801357304216168747609675871348312025478589320767169132448426236131412508780208000261683151027341827977704784635868170164365024153691398281264810213092761244896359928705114964975419909342221566832572080821333186116811553615836546984046708975602900950537616475847728421889679646244945160765353408198901385442487984959953319101723355556602139450399736280750137837615307127761926849034352625200015888535147331611702103968175921510907788019393178114194545257223865541461062892187960223838971476088506276862967146674697562911234082439208160153780889893964518263243671616762179168909779911903754031274622289988005195444414282012187361745992642956581746628302955570299024324153181617210465832036786906117260158783520751516284225540265170483304226143974286933061690897968482590125458327168226458066526769958652682272807075781391858178889652208164348344825993266043367660176999612831860788386150279465955131156552036093988180612138558600301435694527224206344631797460594682573103790084024432438465657245014402821885252470935190620929023136493273497565513958720559654228749774011413346962715422845862377387538230483865688976461927383814900140767310446640259899490222221765904339901886018566526485061799702356193897017860040811889729918311021171229845901641921068884387121855646124960798722908519296819372388642614839657382291123125024186649353143970137428531926649875337218940694281434118520158014123344828015051399694290153483077644569099073152433278288269864602789864321139083506217095002597389863554277196742822248757586765752344220207573630569498825087968928162753848863396909959826280956121450994871701244516461260379029309120889086942028510640182154399457156805941872748998094254742173582401063677404595741785160829230135358081840096996372524230560855903700624271243416909004153690105933983835777939410970027753472000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
    }

    public void testMutualRecursion() {
        def funB
        def funA = { int num -> num == 0 ? 0 : funB.trampoline(num - 1)}.trampoline()
        funB = { int num -> num == 0 ? 0 : funA.trampoline(num - 1)}.trampoline()
        assert 0 == funA(1000)
        assert 0 == funA(2000)
    }

    public void testMutualRecursionWithTrampolineOnFunAOnly() {
        def funB
        def funA = { int num -> num == 0 ? 0 : funB.trampoline(num - 1)}.trampoline()
        funB = { int num -> num == 0 ? 0 : funA.trampoline(num - 1)}
        assert 0 == funA(1000)
        assert 0 == funA(2000)
    }
    
    public void testMutualRecursionWithUserCallingTrampoline() {
        def funB
        def funA = { int num -> num == 0 ? 0 : funB.trampoline(num - 1)}
        funB = { int num -> num == 0 ? 0 : funA.trampoline(num - 1)}
        assert 0 == funA.trampoline(1000)()
        assert 0 == funA.trampoline()(2000)
    }
}