changeModel.groovy

import groovy.xml.XmlUtil

@Grab('com.yourmediashelf.fedora.client:fedora-client-core:0.7')

import static com.yourmediashelf.fedora.client.FedoraClient.*;
import com.yourmediashelf.fedora.client.*
import com.yourmediashelf.fedora.client.response.*
import com.yourmediashelf.fedora.client.request.*

FedoraCredentials credentials = new FedoraCredentials("http://fedoratest.mzk.cz/fedora", "fedoraAdmin", "fedoraAdmin");
FedoraClient fedora = new FedoraClient(credentials);
FedoraRequest.setDefaultClient(fedora);

FedoraResponse r = getDatastreamDissemination("uuid:530719f5-ee95-4449-8ce7-12b0f4cadb22", "DC").execute();
String xml = r.getEntity(String.class);

def response = new XmlParser().parseText(xml)
response.'dc:type'.replaceNode {
    'dc:type'('model:sheetmusic')
}

def changedXml = XmlUtil.serialize(response);

//println(changedXml);