How can I use the Extended Choice Parameter plugin in a Jenkins pipeline script?

Question

The Extended Choice Parameter plugin is great and I use it in jobs configured via the UI https://wiki.jenkins-ci.org/display/JENKINS/Extended+Choice+Parameter+plugin

How

Answer 1

Works for me :

I needed to retrieve all the versions number of artifacts from a Nexus Repo:

 properties ([
    parameters([
        choice(choices: ['PROD', 'DEV', 'QA'], description: '', name: 'ParamEnv' ),   
        string(name: 'ParamVersion', defaultValue: '', description: 'Version to deploy'),
        extendedChoice(
            name: 'someName',
            description: '',
            visibleItemCount: 50,
            multiSelectDelimiter: ',',
            type: 'PT_SINGLE_SELECT',
            groovyScript: '''
            import groovy.json.JsonSlurper
                List nexusPkgV = new ArrayList()        
                def pkgObject = ["curl", "https://xxxx:xxxx@xxxxxxxxxx"].execute().text
                def jsonSlurper = new JsonSlurper()
                def artifactsJsonObject = jsonSlurper.parseText(pkgObject)
                def dataA = artifactsJsonObject.items
                for (i in dataA) {
                    nexusPkgV.add(i.version)
                }
            return nexusPkgV
            '''
        )
    ])
])