Camunda Nashorn Script for getting call activity sub process variables using a script

script.js

  function getCallActivitiesInstanceVariables(targetActivityId, collectionElementVariableName, ignoreVariables) {
        return execution.getProcessEngineServices()
            .getHistoryService().createHistoricActivityInstanceQuery()
            .processInstanceId(execution.getProcessInstanceId())
            .activityId(targetActivityId)
            .list()
            .stream()
            .collect(
                java.util.stream.Collectors.toMap(
                    function (i) {
                        // Set the key of the map to the called process instance ID
                        return i.getCalledProcessInstanceId()
                    },
                    function (i) {
                        // For each called process instance ID, get the sub-processes/called activity's variables
                        // For the return variables remap the objects into Maps with the variable name and value
                        return execution.getProcessEngineServices()
                            .getHistoryService()
                            .createHistoricVariableInstanceQuery()
                            .processInstanceId(i.getCalledProcessInstanceId()).list().stream()
                            .filter(function (i) {
                                return i.getName() != collectionElementVariableName
                            })
                            .filter(function (i) {
                                return !ignoreVariables.contains(i.getName())
                            })
                            .collect(java.util.stream.Collectors.toMap(
                                function (i) {
                                    return i.getName()
                                },
                                function (i) {
                                    return i.getValue()
                                }
                            ))
                    } // end of function
                ) // end of toMap
            ) // end of collect
}

function prependAndFlatten(variables, instanceCodeKey){
    for each(var i in variables.entrySet()){
        var instanceCode = i.getValue().entrySet().stream()
            .filter(function(e){return e.getKey() == instanceCodeKey})
            .findFirst().get().getValue()

        i.setValue(
            i.getValue().entrySet().stream().collect(java.util.stream.Collectors.toMap(
                function(e){return instanceCode + '_' + e.getKey() },
                function(e){ return e.getValue()}
            )).entrySet().stream().filter(function(e){
                return !e.getKey().equals(e.getValue() + '_' + instanceCodeKey)
            }).collect(java.util.stream.Collectors.toMap(function(e){return e.getKey()},function(e){return e.getValue()}))
        )
    }
    var resultVariables = new java.util.HashMap()
    for each(var i in variables.entrySet()){
        resultVariables.putAll(i.getValue())
    }
    return resultVariables
}

    var ignoreThese = new java.util.ArrayList()
    //ignoreThese.add('key')

    var result = getCallActivitiesInstanceVariables('Activity_04vyl5z', 'item', ignoreThese)

    execution.setVariables(prependAndFlatten(result, "key"))