я есть образец XML-файла LEDEShttps://codebeautify.org/xmlviewer/cbdc79e7

Генерируемый класс Ledesxmlebilling21 с использованием JDKxjc как показано ниже и схема Ledes21.xsdhttps://codebeautify.org/xmlviewer/cb974a2e

xjc -d src ledes21.xsd

И я преобразую XML в объект Java, используя JAX-B, как показано ниже

Ledesxmlebilling21 XMLtoObject(InputStream fis) throws Exception {
    JAXBContext context = JAXBContext.newInstance(Ledesxmlebilling21.class)
    Unmarshaller um = context.createUnmarshaller()
    Ledesxmlebilling21 ledes = (Ledesxmlebilling21) um.unmarshal(fis)
    return ledes
}

И я пытаюсь создать карту с объектами InvoiceinvId Значение атрибута как Ключ, а Значения как список всех вложенных атрибутов объекта Invoice.fileItemNbr значения как ниже

['Invoice 31' : [10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33] 
 'Invoice 32' : [50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73] 
]

Может кто-нибудь, пожалуйста, помогите мне с этим?

Обновление с решением

def extractFileItemNbr(input, List<Integer> extracted) {
    input.properties.each { prop, val ->  //LedesXmlRuleProcessor.groovy:82)
        if (prop in ["metaClass", "class"]) return
        if (prop == 'file_item_nbr') {
            extracted << val
        } else {
            extractFileItemNbr(val, extracted)  //LedesXmlRuleProcessor.groovy:87)
        }

    }
}


def extractFileItemNbr(List input, List<Integer> extracted) {
    input.each {
        extractFileItemNbr(it, extracted)
    }
}

void testExtract(Ledesxmlebilling21 ledesxmlebilling21) {
    def xmlInvoices = ledesxmlebilling21.firm.client.invoice.flatten()
    Map<String, List<Integer>> extracted = [:]
    println "invoices -- "+xmlInvoices
    for (Invoice invoice : xmlInvoices) {
        def accuList = []
        extractFileItemNbr(invoice, accuList)
        extracted.put(invoice.invId, accuList)
    }
    println("extracted file_item_nbr "+ extracted)
}

Я получаю ниже исключения с фактическимLedesxmlebilling21 объект

Disconnected from the target VM, address: '127.0.0.1:59759', transport: 'socket'
2017-12-11 11:04:06 - Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Handler dispatch failed; nested exception is java.lang.StackOverflowError] with root cause
java.lang.StackOverflowError: null
    at org.codehaus.groovy.util.AbstractConcurrentMap.getOrPut(AbstractConcurrentMap.java:37)
    at org.codehaus.groovy.reflection.GroovyClassValuePreJava7.get(GroovyClassValuePreJava7.java:94)
    at org.codehaus.groovy.reflection.ClassInfo.getClassInfo(ClassInfo.java:143)
    at org.codehaus.groovy.runtime.metaclass.MetaClassRegistryImpl.getMetaClass(MetaClassRegistryImpl.java:265)
    at org.codehaus.groovy.runtime.InvokerHelper.getMetaClass(InvokerHelper.java:879)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.createPojoMetaClassGetPropertySite(AbstractCallSite.java:351)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.createGetPropertySite(AbstractCallSite.java:327)
    at org.codehaus.groovy.runtime.callsite.GetEffectivePojoPropertySite.acceptGetProperty(GetEffectivePojoPropertySite.java:56)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callGetProperty(AbstractCallSite.java:296)
    at com.validation.rule.processor.impl.LedesXmlRuleProcessor.extractFileItemNbr(LedesXmlRuleProcessor.groovy:82)
    at sun.reflect.GeneratedMethodAccessor82.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:93)
    at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:325)
    at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:384)
    at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1027)
    at org.codehaus.groovy.runtime.callsite.PogoMetaClassSite.callCurrent(PogoMetaClassSite.java:69)
    at org.codehaus.groovy.runtime.callsite.AbstractCallSite.callCurrent(AbstractCallSite.java:174)
    at com.validation.rule.processor.impl.LedesXmlRuleProcessor$_extractFileItemNbr_closure2.doCall(LedesXmlRuleProcessor.groovy:87)