How to pass multiple optional parameters and one mandatory parameter in groovy? [duplicate] - groovy

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".

Answer 3

Just a simplification of the Tim's answer. The groovy way to do it is using a map, as already suggested, but then let's put the mandatory parameters also in the map. This will look like this:
def someMethod(def args) {
println "MANDATORY1=${args.mandatory1}"
println "MANDATORY2=${args.mandatory2}"
println "OPTIONAL1=${args?.optional1}"
println "OPTIONAL2=${args?.optional2}"
}
someMethod mandatory1:1, mandatory2:2, optional1:3
with the output:
MANDATORY1=1
MANDATORY2=2
OPTIONAL1=3
OPTIONAL2=null
This looks nicer and the advantage of this is that you can change the order of the parameters as you like.

Answer 4

We can Deal with Optional parameters in 2 ways
Creating the method parameter with null values:
def generateReview(def id, def createDate=null) {
return new Review(id, createDate ?: new Date()) // ?: short hand of ternary operator
}
generateReview(id) // createDate is not passed
generateReview(id, createDate) // createDate is passed
Using Java Optional.of()
def generateReview(def id, Optional<Date> createDate) {
return new Review(id, createDate.isPresent() ? createDate.get() : new Date())
}
generateReview(id, Optional.empty()) // createDate is not passed
generateReview(id, Optional.of(createDate)) // createDate is passed