Groovy method with optional parameters

Question

I would like to write a wrapper method for a webservice, the service accepts 2 mandatory and 3 optional parameters.

To have a shorter example, I would like to get the following code working

def myMethod(pParm1='1', pParm2='2') {     println "${pParm1}${pParm2}" }  myMethod(); myMethod('a') myMethod(pParm2:'a') // doesn't work as expected myMethod('b','c') 

The output is:

12 a2 [pParm2:a]2 a2 bc 

What I would like to achieve is to give one parameter and get 1a as the result. Is this possible (in the laziest way)?

Answer 1

Can't be done as it stands... The code

def myMethod(pParm1='1', pParm2='2'){     println "${pParm1}${pParm2}" } 

Basically makes groovy create the following methods:

Object myMethod( pParm1, pParm2 ) {     println "$pParm1$pParm2" }  Object myMethod( pParm1 ) {     this.myMethod( pParm1, '2' ) }  Object myMethod() {     this.myMethod( '1', '2' ) } 

One alternative would be to have an optional Map as the first param:

def myMethod( Map map = [:], String mandatory1, String mandatory2 ){     println "${mandatory1} ${mandatory2} ${map.parm1 ?: '1'} ${map.parm2 ?: '2'}" }  myMethod( 'a', 'b' )                // prints 'a b 1 2' myMethod( 'a', 'b', parm1:'value' ) // prints 'a b value 2' myMethod( 'a', 'b', parm2:'2nd')    // prints 'a b 1 2nd' 

Obviously, documenting this so other people know what goes in the magical map and what the defaults are is left to the reader ;-)

Answer 2

You can use arguments with default values.

def someMethod(def mandatory,def optional=null){} 

if argument "optional" not exist, it turns to "null".