X-Git-Url: https://gerrit.onap.org/r/gitweb?a=blobdiff_plain;f=src%2Fmain%2Fjava%2Forg%2Fonap%2Faai%2Fmodelloader%2Frestclient%2FAaiRestClient.java;h=a2a4c5bdfee41d436d6fd76aa630a7e669997a5d;hb=270656abb1ed24930b2f9e57f5bef659494f5e8e;hp=50c8bf038d3280d2dd96071a281f3a20c17097a4;hpb=af1121fa58761e9516ce784d60ebe2a65d9d9992;p=aai%2Fmodel-loader.git diff --git a/src/main/java/org/onap/aai/modelloader/restclient/AaiRestClient.java b/src/main/java/org/onap/aai/modelloader/restclient/AaiRestClient.java index 50c8bf0..a2a4c5b 100644 --- a/src/main/java/org/onap/aai/modelloader/restclient/AaiRestClient.java +++ b/src/main/java/org/onap/aai/modelloader/restclient/AaiRestClient.java @@ -2,15 +2,14 @@ * ============LICENSE_START======================================================= * org.onap.aai * ================================================================================ - * Copyright © 2017 AT&T Intellectual Property. - * Copyright © 2017 Amdocs - * All rights reserved. + * Copyright © 2017-2018 AT&T Intellectual Property. All rights reserved. + * Copyright © 2017-2018 European Software Marketing Ltd. * ================================================================================ * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * - * http://www.apache.org/licenses/LICENSE-2.0 + * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, @@ -18,466 +17,195 @@ * See the License for the specific language governing permissions and * limitations under the License. * ============LICENSE_END========================================================= - * - * ECOMP is a trademark and service mark of AT&T Intellectual Property. */ package org.onap.aai.modelloader.restclient; -import com.sun.jersey.api.client.Client; -import com.sun.jersey.api.client.ClientResponse; -import com.sun.jersey.api.client.config.ClientConfig; -import com.sun.jersey.api.client.config.DefaultClientConfig; -import com.sun.jersey.api.client.filter.LoggingFilter; -import com.sun.jersey.client.urlconnection.HTTPSProperties; - -import org.onap.aai.modelloader.config.ModelLoaderConfig; -import org.onap.aai.modelloader.restclient.AaiRestClient; -import org.onap.aai.modelloader.service.ModelLoaderMsgs; -import org.onap.aai.cl.api.LogFields; -import org.onap.aai.cl.api.LogLine; +import com.sun.jersey.core.util.MultivaluedMapImpl; // NOSONAR +import java.io.IOException; +import java.io.StringReader; +import java.net.URI; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import java.util.stream.IntStream; +import javax.ws.rs.core.MediaType; +import javax.ws.rs.core.MultivaluedMap; +import javax.ws.rs.core.Response; +import javax.ws.rs.core.UriBuilder; +import javax.xml.parsers.DocumentBuilder; +import javax.xml.parsers.DocumentBuilderFactory; +import javax.xml.parsers.ParserConfigurationException; import org.onap.aai.cl.api.Logger; import org.onap.aai.cl.eelf.LoggerFactory; -import org.onap.aai.cl.mdc.MdcContext; -import org.onap.aai.cl.mdc.MdcOverride; +import org.onap.aai.modelloader.config.ModelLoaderConfig; +import org.onap.aai.modelloader.service.ModelLoaderMsgs; +import org.onap.aai.restclient.client.OperationResult; +import org.onap.aai.restclient.client.RestClient; +import org.onap.aai.restclient.enums.RestAuthenticationMode; import org.w3c.dom.Document; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.InputSource; import org.xml.sax.SAXException; -import java.io.ByteArrayOutputStream; -import java.io.FileInputStream; -import java.io.IOException; -import java.io.PrintStream; -import java.io.StringReader; -import java.security.GeneralSecurityException; -import java.security.KeyStore; -import java.security.cert.X509Certificate; -import java.text.SimpleDateFormat; - -import javax.net.ssl.HostnameVerifier; -import javax.net.ssl.HttpsURLConnection; -import javax.net.ssl.KeyManagerFactory; -import javax.net.ssl.SSLContext; -import javax.net.ssl.SSLSession; -import javax.net.ssl.TrustManager; -import javax.net.ssl.X509TrustManager; -import javax.ws.rs.core.Response; -import javax.xml.parsers.DocumentBuilder; -import javax.xml.parsers.DocumentBuilderFactory; -import javax.xml.parsers.ParserConfigurationException; - +/** + * Wrapper around the standard A&AI Rest Client interface. This currently uses Jersey client 1.x + * + */ public class AaiRestClient { - public enum MimeType { - XML("application/xml"), JSON("application/json"); - - private String httpType; - - MimeType(String httpType) { - this.httpType = httpType; - } - - String getHttpHeaderType() { - return httpType; - } - } - - private static String HEADER_TRANS_ID = "X-TransactionId"; - private static String HEADER_FROM_APP_ID = "X-FromAppId"; - private static String HEADER_AUTHORIZATION = "Authorization"; - private static String ML_APP_NAME = "ModelLoader"; - private static String RESOURCE_VERSION_PARAM = "resource-version"; - private static SimpleDateFormat dateFormatter = new SimpleDateFormat( - "yyyy-MM-dd'T'HH:mm:ss.SSSXXX"); + public static final String HEADER_TRANS_ID = "X-TransactionId"; + public static final String HEADER_FROM_APP_ID = "X-FromAppId"; + public static final String ML_APP_NAME = "ModelLoader"; + private static final String RESOURCE_VERSION_PARAM = "resource-version"; - private static Logger logger = LoggerFactory.getInstance() - .getLogger(AaiRestClient.class.getName()); - private static Logger metricsLogger = LoggerFactory.getInstance() - .getMetricsLogger(AaiRestClient.class.getName()); + private static Logger logger = LoggerFactory.getInstance().getLogger(AaiRestClient.class.getName()); - private ModelLoaderConfig config = null; + private ModelLoaderConfig config = null; - public AaiRestClient(ModelLoaderConfig config) { - this.config = config; - } - - /** - * Send a PUT request to the A&AI. - * - * @param url - * - the url - * @param transId - * - transaction ID - * @param payload - * - the XML or JSON payload for the request - * @param mimeType - * - the content type (XML or JSON) - * @return ClientResponse - */ - public ClientResponse putResource(String url, String payload, String transId, MimeType mimeType) { - ClientResponse result = null; - ByteArrayOutputStream baos = new ByteArrayOutputStream(); - long startTimeInMs = 0; - MdcOverride override = new MdcOverride(); - - try { - Client client = setupClient(); - - baos = new ByteArrayOutputStream(); - PrintStream ps = new PrintStream(baos); - if (logger.isDebugEnabled()) { - client.addFilter(new LoggingFilter(ps)); - } + public AaiRestClient(ModelLoaderConfig config) { + this.config = config; + } - // Grab the current time so that we can use it for metrics purposes later. - startTimeInMs = System.currentTimeMillis(); - override.addAttribute(MdcContext.MDC_START_TIME, dateFormatter.format(startTimeInMs)); - if (useBasicAuth()) { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME) - .header(HEADER_AUTHORIZATION, getAuthenticationCredentials()) - .type(mimeType.getHttpHeaderType()).put(ClientResponse.class, payload); - } else { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME).type(mimeType.getHttpHeaderType()) - .put(ClientResponse.class, payload); - } - } catch (Exception ex) { - logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "PUT", url, ex.getLocalizedMessage()); - return null; - } finally { - if (logger.isDebugEnabled()) { - logger.debug(baos.toString()); - } + /** + * Send a GET request to the A&AI for a resource. + * + * @param url + * @param transId + * @param mediaType + * @return + */ + public OperationResult getResource(String url, String transId, MediaType mediaType) { + return setupClient().get(url, buildHeaders(transId), mediaType); } - if ((result != null) && ((result.getStatus() == Response.Status.CREATED.getStatusCode()) - || (result.getStatus() == Response.Status.OK.getStatusCode()))) { - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, "PUT", url, - Integer.toString(result.getStatus())); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()) - .setField(LogLine.DefinedFields.RESPONSE_DESCRIPTION, - result.getResponseStatus().toString()), - override, "PUT", url, Integer.toString(result.getStatus())); - } else { - // If response is not 200 OK, then additionally log the reason - String respMsg = result.getEntity(String.class); - if (respMsg == null) { - respMsg = result.getStatusInfo().getReasonPhrase(); - } - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_UNSUCCESSFUL, "PUT", url, - Integer.toString(result.getStatus()), respMsg); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_UNSUCCESSFUL, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()) - .setField(LogLine.DefinedFields.RESPONSE_DESCRIPTION, - result.getResponseStatus().toString()), - override, "PUT", url, Integer.toString(result.getStatus()), respMsg); + /** + * Send a PUT request to the A&AI. + * + * @param url - the url + * @param payload - the XML or JSON payload for the request + * @param transId - transaction ID + * @param mediaType - the content type (XML or JSON) + * @return operation result + */ + public OperationResult putResource(String url, String payload, String transId, MediaType mediaType) { + logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_PAYLOAD, payload); + return setupClient().put(url, payload, buildHeaders(transId), mediaType, mediaType); } - return result; - } - /** - * Send a DELETE request to the A&AI. - * - * @param url - * - the url - * @param resourceVersion - * - the resource-version of the model to delete - * @param transId - * - transaction ID - * @return ClientResponse - */ - public ClientResponse deleteResource(String url, String resourceVersion, String transId) { - ClientResponse result = null; - ByteArrayOutputStream baos = new ByteArrayOutputStream(); - long startTimeInMs = 0; - MdcOverride override = new MdcOverride(); - - try { - Client client = setupClient(); - - baos = new ByteArrayOutputStream(); - PrintStream ps = new PrintStream(baos); - if (logger.isDebugEnabled()) { - client.addFilter(new LoggingFilter(ps)); - } - - // Grab the current time so that we can use it for metrics purposes later. - startTimeInMs = System.currentTimeMillis(); - override.addAttribute(MdcContext.MDC_START_TIME, dateFormatter.format(startTimeInMs)); - - if (useBasicAuth()) { - result = client.resource(url).queryParam(RESOURCE_VERSION_PARAM, resourceVersion) - .header(HEADER_TRANS_ID, transId).header(HEADER_FROM_APP_ID, ML_APP_NAME) - .header(HEADER_AUTHORIZATION, getAuthenticationCredentials()) - .delete(ClientResponse.class); - } else { - result = client.resource(url).queryParam(RESOURCE_VERSION_PARAM, resourceVersion) - .header(HEADER_TRANS_ID, transId).header(HEADER_FROM_APP_ID, ML_APP_NAME) - .delete(ClientResponse.class); - } - } catch (Exception ex) { - logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "DELETE", url, ex.getLocalizedMessage()); - return null; - } finally { - if (logger.isDebugEnabled()) { - logger.debug(baos.toString()); - } + /** + * Send a POST request to the A&AI. + * + * @param url - the url + * @param transId - transaction ID + * @param payload - the XML or JSON payload for the request + * @param mimeType - the content type (XML or JSON) + * @return ClientResponse + */ + public OperationResult postResource(String url, String payload, String transId, MediaType mediaType) { + logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_PAYLOAD, payload); + return setupClient().post(url, payload, buildHeaders(transId), mediaType, mediaType); } - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, "DELETE", url, - Integer.toString(result.getStatus())); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()).setField( - LogLine.DefinedFields.RESPONSE_DESCRIPTION, result.getResponseStatus().toString()), - override, "DELETE", url, Integer.toString(result.getStatus())); - - return result; - } - - /** - * Send a GET request to the A&AI for a resource. - * - * @param url - * - the url to use - * @param transId - * - transaction ID - * @return ClientResponse - */ - public ClientResponse getResource(String url, String transId, MimeType mimeType) { - ClientResponse result = null; - ByteArrayOutputStream baos = new ByteArrayOutputStream(); - long startTimeInMs = 0; - MdcOverride override = new MdcOverride(); - - try { - Client client = setupClient(); - - baos = new ByteArrayOutputStream(); - PrintStream ps = new PrintStream(baos); - if (logger.isDebugEnabled()) { - client.addFilter(new LoggingFilter(ps)); - } - - // Grab the current time so that we can use it for metrics purposes later. - startTimeInMs = System.currentTimeMillis(); - override.addAttribute(MdcContext.MDC_START_TIME, dateFormatter.format(startTimeInMs)); - if (useBasicAuth()) { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME).accept(mimeType.getHttpHeaderType()) - .header(HEADER_AUTHORIZATION, getAuthenticationCredentials()).get(ClientResponse.class); - } else { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME).accept(mimeType.getHttpHeaderType()) - .get(ClientResponse.class); - - } - } catch (Exception ex) { - logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "GET", url, ex.getLocalizedMessage()); - return null; - } finally { - if (logger.isDebugEnabled()) { - logger.debug(baos.toString()); - } + /** + * Send a DELETE request to the A&AI. + * + * @param url - the url + * @param resourceVersion - the resource-version of the model to delete + * @param transId - transaction ID + * @return ClientResponse + */ + public OperationResult deleteResource(String url, String resourceVersion, String transId) { + URI uri = UriBuilder.fromUri(url).queryParam(RESOURCE_VERSION_PARAM, resourceVersion).build(); + return setupClient().delete(uri.toString(), buildHeaders(transId), null); } - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, "GET", url, - Integer.toString(result.getStatus())); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()).setField( - LogLine.DefinedFields.RESPONSE_DESCRIPTION, result.getResponseStatus().toString()), - override, "GET", url, Integer.toString(result.getStatus())); - - return result; - } - - /** - * Send a POST request to the A&AI. - * - * @param url - * - the url - * @param transId - * - transaction ID - * @param payload - * - the XML or JSON payload for the request - * @param mimeType - * - the content type (XML or JSON) - * @return ClientResponse - */ - public ClientResponse postResource(String url, String payload, String transId, MimeType mimeType) { - ClientResponse result = null; - ByteArrayOutputStream baos = new ByteArrayOutputStream(); - long startTimeInMs = 0; - MdcOverride override = new MdcOverride(); - - try { - Client client = setupClient(); - - baos = new ByteArrayOutputStream(); - PrintStream ps = new PrintStream(baos); - if (logger.isDebugEnabled()) { - client.addFilter(new LoggingFilter(ps)); - } - - // Grab the current time so that we can use it for metrics purposes later. - startTimeInMs = System.currentTimeMillis(); - override.addAttribute(MdcContext.MDC_START_TIME, dateFormatter.format(startTimeInMs)); - - if (useBasicAuth()) { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME) - .header(HEADER_AUTHORIZATION, getAuthenticationCredentials()) - .type(mimeType.getHttpHeaderType()).post(ClientResponse.class, payload); - } else { - result = client.resource(url).header(HEADER_TRANS_ID, transId) - .header(HEADER_FROM_APP_ID, ML_APP_NAME).type(mimeType.getHttpHeaderType()) - .post(ClientResponse.class, payload); - } - } catch (Exception ex) { - logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "POST", url, ex.getLocalizedMessage()); - return null; - } finally { - if (logger.isDebugEnabled()) { - logger.debug(baos.toString()); - } + /** + * Does a GET on a resource to retrieve the resource version, and then DELETE that version. + * + * @param url - the url + * @param transId - transaction ID + * @return ClientResponse + */ + public OperationResult getAndDeleteResource(String url, String transId) { + // First, GET the model + OperationResult getResponse = getResource(url, transId, MediaType.APPLICATION_XML_TYPE); + if (getResponse == null || getResponse.getResultCode() != Response.Status.OK.getStatusCode()) { + return getResponse; + } + + // Delete the model using the resource version in the response + String resVersion = null; + try { + resVersion = getResourceVersion(getResponse); + } catch (Exception e) { + logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "GET", url, e.getLocalizedMessage()); + return null; + } + + return deleteResource(url, resVersion, transId); } - if ((result != null) && ((result.getStatus() == Response.Status.CREATED.getStatusCode()) - || (result.getStatus() == Response.Status.OK.getStatusCode()))) { - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, "POST", url, - Integer.toString(result.getStatus())); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_SUCCESS, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()) - .setField(LogLine.DefinedFields.RESPONSE_DESCRIPTION, - result.getResponseStatus().toString()), - override, "POST", url, Integer.toString(result.getStatus())); - } else { - // If response is not 200 OK, then additionally log the reason - String respMsg = result.getEntity(String.class); - if (respMsg == null) { - respMsg = result.getStatusInfo().getReasonPhrase(); - } - logger.info(ModelLoaderMsgs.AAI_REST_REQUEST_UNSUCCESSFUL, "POST", url, - Integer.toString(result.getStatus()), respMsg); - metricsLogger.info(ModelLoaderMsgs.AAI_REST_REQUEST_UNSUCCESSFUL, - new LogFields().setField(LogLine.DefinedFields.RESPONSE_CODE, result.getStatus()) - .setField(LogLine.DefinedFields.RESPONSE_DESCRIPTION, - result.getResponseStatus().toString()), - override, "POST", url, Integer.toString(result.getStatus()), respMsg); - } - return result; - } - - /** - * Does a GET on a resource to retrieve the resource version, and then DELETE - * that version. - * - * @param url - * - the url - * @param transId - * - transaction ID - * @return ClientResponse - */ - public ClientResponse getAndDeleteResource(String url, String transId) { - // First, GET the model - ClientResponse getResponse = getResource(url, transId, MimeType.XML); - if ((getResponse == null) || (getResponse.getStatus() != Response.Status.OK.getStatusCode())) { - return getResponse; + public boolean useBasicAuth() { + return config.getAaiAuthenticationUser() != null && config.getAaiAuthenticationPassword() != null; } - // Delete the model using the resource version in the response - String resVersion = null; - try { - resVersion = getResourceVersion(getResponse); - } catch (Exception e) { - logger.error(ModelLoaderMsgs.AAI_REST_REQUEST_ERROR, "GET", url, e.getLocalizedMessage()); - return null; + private RestClient setupClient() { + RestClient restClient = new RestClient(); + + // @formatter:off + restClient.validateServerHostname(false) + .validateServerCertChain(false) + .clientCertFile(config.getAaiKeyStorePath()) + .clientCertPassword(config.getAaiKeyStorePassword()) + .connectTimeoutMs(120000) + .readTimeoutMs(120000); + // @formatter:on + + if (useBasicAuth()) { + restClient.authenticationMode(RestAuthenticationMode.SSL_BASIC); + restClient.basicAuthUsername(config.getAaiAuthenticationUser()); + restClient.basicAuthPassword(config.getAaiAuthenticationPassword()); + } + + return restClient; } - return deleteResource(url, resVersion, transId); - } - - private Client setupClient() throws IOException, GeneralSecurityException { - ClientConfig clientConfig = new DefaultClientConfig(); - - HttpsURLConnection.setDefaultHostnameVerifier(new HostnameVerifier() { - @Override - public boolean verify(String string, SSLSession ssls) { - return true; - } - }); - - // Create a trust manager that does not validate certificate chains - TrustManager[] trustAllCerts = new TrustManager[] { new X509TrustManager() { - @Override - public X509Certificate[] getAcceptedIssuers() { - return null; - } - - @Override - public void checkClientTrusted(X509Certificate[] certs, String authType) {} - - @Override - public void checkServerTrusted(X509Certificate[] certs, String authType) {} - } }; - - SSLContext ctx = SSLContext.getInstance("TLS"); - KeyManagerFactory kmf = KeyManagerFactory.getInstance("SunX509"); - FileInputStream fin = new FileInputStream(config.getAaiKeyStorePath()); - KeyStore ks = KeyStore.getInstance("PKCS12"); - char[] pwd = config.getAaiKeyStorePassword().toCharArray(); - ks.load(fin, pwd); - kmf.init(ks, pwd); - - ctx.init(kmf.getKeyManagers(), trustAllCerts, null); - clientConfig.getProperties().put(HTTPSProperties.PROPERTY_HTTPS_PROPERTIES, - new HTTPSProperties(new HostnameVerifier() { - @Override - public boolean verify(String theString, SSLSession sslSession) { - return true; - } - }, ctx)); - - Client client = Client.create(clientConfig); - - return client; - } - - private String getResourceVersion(ClientResponse response) - throws ParserConfigurationException, SAXException, IOException { - String respData = response.getEntity(String.class); - - DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); - DocumentBuilder builder = factory.newDocumentBuilder(); - InputSource is = new InputSource(new StringReader(respData)); - Document doc = builder.parse(is); - - NodeList nodeList = doc.getDocumentElement().getChildNodes(); - for (int i = 0; i < nodeList.getLength(); i++) { - Node currentNode = nodeList.item(i); - if (currentNode.getNodeName().equals(RESOURCE_VERSION_PARAM)) { - return currentNode.getTextContent(); - } + /** + * Create the HTTP headers required for an A&AI operation (GET/POST/PUT/DELETE) + * + * @param transId + * @return map of headers + */ + private Map> buildHeaders(String transId) { + MultivaluedMap headers = new MultivaluedMapImpl(); + headers.put(HEADER_TRANS_ID, Collections.singletonList(transId)); + headers.put(HEADER_FROM_APP_ID, Collections.singletonList(ML_APP_NAME)); + return headers; } - return null; - } - - private String getAuthenticationCredentials() { - - String usernameAndPassword = config.getAaiAuthenticationUser() + ":" - + config.getAaiAuthenticationPassword(); - return "Basic " + java.util.Base64.getEncoder().encodeToString(usernameAndPassword.getBytes()); - } - - public boolean useBasicAuth() { - return (config.getAaiAuthenticationUser() != null) - && (config.getAaiAuthenticationPassword() != null); - } + private String getResourceVersion(OperationResult getResponse) + throws ParserConfigurationException, SAXException, IOException { + String respData = getResponse.getResult(); + + DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); + factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true); + DocumentBuilder builder = factory.newDocumentBuilder(); + InputSource is = new InputSource(new StringReader(respData)); + Document doc = builder.parse(is); + + NodeList nodesList = doc.getDocumentElement().getChildNodes(); + + // @formatter:off + return IntStream.range(0, nodesList.getLength()).mapToObj(nodesList::item) + .filter(childNode -> childNode.getNodeName().equals(RESOURCE_VERSION_PARAM)) + .findFirst() + .map(Node::getTextContent) + .orElse(null); + // @formatter:on + } }