Java tutorial
/* * Licensed to the Apache Software Foundation (ASF) under one or more * contributor license agreements. See the NOTICE file distributed with * this work for additional information regarding copyright ownership. * The ASF licenses this file to You 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 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.apache.nifi.fingerprint; import org.apache.commons.lang3.StringUtils; import org.apache.nifi.components.ConfigurableComponent; import org.apache.nifi.components.PropertyDescriptor; import org.apache.nifi.controller.ControllerService; import org.apache.nifi.controller.FlowController; import org.apache.nifi.controller.exception.ProcessorInstantiationException; import org.apache.nifi.controller.serialization.FlowFromDOMFactory; import org.apache.nifi.encrypt.StringEncryptor; import org.apache.nifi.nar.ExtensionManager; import org.apache.nifi.processor.Processor; import org.apache.nifi.reporting.ReportingTask; import org.apache.nifi.util.DomUtils; import org.apache.nifi.web.api.dto.ControllerServiceDTO; import org.apache.nifi.web.api.dto.ReportingTaskDTO; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import org.w3c.dom.Document; import org.w3c.dom.Element; import org.w3c.dom.Node; import org.w3c.dom.NodeList; import org.xml.sax.SAXException; import javax.xml.XMLConstants; import javax.xml.parsers.DocumentBuilder; import javax.xml.parsers.DocumentBuilderFactory; import javax.xml.validation.Schema; import javax.xml.validation.SchemaFactory; import java.io.ByteArrayInputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.security.NoSuchAlgorithmException; import java.util.ArrayList; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.Map; import java.util.SortedMap; import java.util.TreeMap; import java.util.UUID; /** * <p>Creates a fingerprint of a flow.xml. The order of elements or attributes in the flow.xml does not influence the fingerprint generation. * * <p>Only items in the flow.xml that influence the processing of data are incorporated into the fingerprint. * Examples of items involved in the fingerprint are: processor IDs, processor relationships, and processor properties. * Examples of items not involved in the fingerprint are: items in the processor "comments" tabs, position information, flow controller settings, and counters. * * <p>The determination for making items into the fingerprint is whether we can * easily change the setting in order to inherit the cluster's flow. * For example, if the component has to be stopped to apply the change and started again, * then the item should be included in a fingerprint. */ public class FingerprintFactory { /* * Developer Note: This class should be changed with care and coordinated * with all classes that use fingerprinting. Improper coordination may * lead to orphaning flow files, especially when flows are reloaded in a * clustered environment. */ // no fingerprint value public static final String NO_VALUE = "NO_VALUE"; static final String FLOW_CONFIG_XSD = "/FlowConfiguration.xsd"; private static final String ENCRYPTED_VALUE_PREFIX = "enc{"; private static final String ENCRYPTED_VALUE_SUFFIX = "}"; private final StringEncryptor encryptor; private final DocumentBuilder flowConfigDocBuilder; private static final Logger logger = LoggerFactory.getLogger(FingerprintFactory.class); public FingerprintFactory(final StringEncryptor encryptor) { this.encryptor = encryptor; final DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance(); documentBuilderFactory.setNamespaceAware(true); final SchemaFactory schemaFactory = SchemaFactory.newInstance(XMLConstants.W3C_XML_SCHEMA_NS_URI); final Schema schema; try { schema = schemaFactory.newSchema(FingerprintFactory.class.getResource(FLOW_CONFIG_XSD)); } catch (final Exception e) { throw new RuntimeException("Failed to parse schema for file flow configuration.", e); } try { documentBuilderFactory.setSchema(schema); flowConfigDocBuilder = documentBuilderFactory.newDocumentBuilder(); } catch (final Exception e) { throw new RuntimeException("Failed to create document builder for flow configuration.", e); } } public FingerprintFactory(final StringEncryptor encryptor, final DocumentBuilder docBuilder) { this.encryptor = encryptor; this.flowConfigDocBuilder = docBuilder; } /** * Creates a fingerprint of a flow. The order of elements or attributes in the flow does not influence the fingerprint generation. * This method does not accept a FlowController, which means that Processors cannot be created in order to verify default property * values, etc. As a result, if Flow A and Flow B are fingerprinted and Flow B, for instance, contains a property with a default value * that is not present in Flow A, then the two will have different fingerprints. * * @param flowBytes the flow represented as bytes * * @return a generated fingerprint * * @throws FingerprintException if the fingerprint failed to be generated */ public synchronized String createFingerprint(final byte[] flowBytes) throws FingerprintException { return createFingerprint(flowBytes, null); } /** * Creates a fingerprint of a flow. The order of elements or attributes in the flow does not influence the fingerprint generation. * * @param flowBytes the flow represented as bytes * @param controller the controller * * @return a generated fingerprint * * @throws FingerprintException if the fingerprint failed to be generated */ public synchronized String createFingerprint(final byte[] flowBytes, final FlowController controller) throws FingerprintException { try { return createFingerprint(parseFlow(flowBytes), controller); } catch (final NoSuchAlgorithmException e) { throw new FingerprintException(e); } } /** * Creates a fingerprint from an XML document representing the flow.xml. * * @param flowDoc the DOM * * @return the fingerprint * * @throws NoSuchAlgorithmException ex * @throws UnsupportedEncodingException ex */ private String createFingerprint(final Document flowDoc, final FlowController controller) throws NoSuchAlgorithmException { if (flowDoc == null) { return ""; } // builder to hold fingerprint state final StringBuilder fingerprintBuilder = new StringBuilder(); // add flow controller fingerprint final Element flowControllerElem = flowDoc.getDocumentElement(); if (flowControllerElem == null) { logger.warn("Unable to create fingerprint because no 'flowController' element found in XML."); return ""; } addFlowControllerFingerprint(fingerprintBuilder, flowControllerElem, controller); return fingerprintBuilder.toString(); } /** * Parse the given flow.xml bytes into a Document instance. * * @param flow a flow * * @return the DOM * * @throws FingerprintException if the flow could not be parsed */ private Document parseFlow(final byte[] flow) throws FingerprintException { if (flow == null || flow.length == 0) { return null; } try { return flowConfigDocBuilder.parse(new ByteArrayInputStream(flow)); } catch (final SAXException | IOException ex) { throw new FingerprintException(ex); } } private StringBuilder addFlowControllerFingerprint(final StringBuilder builder, final Element flowControllerElem, final FlowController controller) { // root group final Element rootGroupElem = (Element) DomUtils.getChildNodesByTagName(flowControllerElem, "rootGroup") .item(0); addProcessGroupFingerprint(builder, rootGroupElem, controller); final Element controllerServicesElem = DomUtils.getChild(flowControllerElem, "controllerServices"); if (controllerServicesElem != null) { final List<ControllerServiceDTO> serviceDtos = new ArrayList<>(); for (final Element serviceElem : DomUtils.getChildElementsByTagName(controllerServicesElem, "controllerService")) { final ControllerServiceDTO dto = FlowFromDOMFactory.getControllerService(serviceElem, encryptor); serviceDtos.add(dto); } Collections.sort(serviceDtos, new Comparator<ControllerServiceDTO>() { @Override public int compare(final ControllerServiceDTO o1, final ControllerServiceDTO o2) { if (o1 == null && o2 == null) { return 0; } if (o1 == null && o2 != null) { return 1; } if (o1 != null && o2 == null) { return -1; } return o1.getId().compareTo(o2.getId()); } }); for (final ControllerServiceDTO dto : serviceDtos) { addControllerServiceFingerprint(builder, dto, controller); } } final Element reportingTasksElem = DomUtils.getChild(flowControllerElem, "reportingTasks"); if (reportingTasksElem != null) { final List<ReportingTaskDTO> reportingTaskDtos = new ArrayList<>(); for (final Element taskElem : DomUtils.getChildElementsByTagName(reportingTasksElem, "reportingTask")) { final ReportingTaskDTO dto = FlowFromDOMFactory.getReportingTask(taskElem, encryptor); reportingTaskDtos.add(dto); } Collections.sort(reportingTaskDtos, new Comparator<ReportingTaskDTO>() { @Override public int compare(final ReportingTaskDTO o1, final ReportingTaskDTO o2) { if (o1 == null && o2 == null) { return 0; } if (o1 == null && o2 != null) { return 1; } if (o1 != null && o2 == null) { return -1; } return o1.getId().compareTo(o2.getId()); } }); for (final ReportingTaskDTO dto : reportingTaskDtos) { addReportingTaskFingerprint(builder, dto, controller); } } return builder; } private StringBuilder addProcessGroupFingerprint(final StringBuilder builder, final Element processGroupElem, final FlowController controller) throws FingerprintException { // id appendFirstValue(builder, DomUtils.getChildNodesByTagName(processGroupElem, "id")); // processors final List<Element> processorElems = DomUtils.getChildElementsByTagName(processGroupElem, "processor"); Collections.sort(processorElems, getIdsComparator()); for (final Element processorElem : processorElems) { addFlowFileProcessorFingerprint(builder, processorElem, controller); } // input ports final NodeList inputPortElems = DomUtils.getChildNodesByTagName(processGroupElem, "inputPort"); final List<Element> sortedInputPortElems = sortElements(inputPortElems, getIdsComparator()); for (final Element inputPortElem : sortedInputPortElems) { addPortFingerprint(builder, inputPortElem); } // labels final NodeList labelElems = DomUtils.getChildNodesByTagName(processGroupElem, "label"); final List<Element> sortedLabels = sortElements(labelElems, getIdsComparator()); for (final Element labelElem : sortedLabels) { addLabelFingerprint(builder, labelElem); } // output ports final NodeList outputPortElems = DomUtils.getChildNodesByTagName(processGroupElem, "outputPort"); final List<Element> sortedOutputPortElems = sortElements(outputPortElems, getIdsComparator()); for (final Element outputPortElem : sortedOutputPortElems) { addPortFingerprint(builder, outputPortElem); } // process groups final NodeList nestedProcessGroupElems = DomUtils.getChildNodesByTagName(processGroupElem, "processGroup"); final List<Element> sortedNestedProcessGroupElems = sortElements(nestedProcessGroupElems, getIdsComparator()); for (final Element nestedProcessGroupElem : sortedNestedProcessGroupElems) { addProcessGroupFingerprint(builder, nestedProcessGroupElem, controller); } // remote process groups final NodeList remoteProcessGroupElems = DomUtils.getChildNodesByTagName(processGroupElem, "remoteProcessGroup"); final List<Element> sortedRemoteProcessGroupElems = sortElements(remoteProcessGroupElems, getIdsComparator()); for (final Element remoteProcessGroupElem : sortedRemoteProcessGroupElems) { addRemoteProcessGroupFingerprint(builder, remoteProcessGroupElem); } // connections final NodeList connectionElems = DomUtils.getChildNodesByTagName(processGroupElem, "connection"); final List<Element> sortedConnectionElems = sortElements(connectionElems, getIdsComparator()); for (final Element connectionElem : sortedConnectionElems) { addConnectionFingerprint(builder, connectionElem); } // funnel final NodeList funnelElems = DomUtils.getChildNodesByTagName(processGroupElem, "funnel"); final List<Element> sortedFunnelElems = sortElements(funnelElems, getIdsComparator()); for (final Element funnelElem : sortedFunnelElems) { addFunnelFingerprint(builder, funnelElem); } return builder; } private StringBuilder addFlowFileProcessorFingerprint(final StringBuilder builder, final Element processorElem, final FlowController controller) throws FingerprintException { // id appendFirstValue(builder, DomUtils.getChildNodesByTagName(processorElem, "id")); // class final NodeList childNodes = DomUtils.getChildNodesByTagName(processorElem, "class"); final String className = childNodes.item(0).getTextContent(); appendFirstValue(builder, childNodes); // annotation data appendFirstValue(builder, DomUtils.getChildNodesByTagName(processorElem, "annotationData")); // create an instance of the Processor so that we know the default property values Processor processor = null; try { if (controller != null) { processor = controller.createProcessor(className, UUID.randomUUID().toString(), false) .getProcessor(); } } catch (ProcessorInstantiationException e) { logger.warn( "Unable to create Processor of type {} due to {}; its default properties will be fingerprinted instead of being ignored.", className, e.toString()); if (logger.isDebugEnabled()) { logger.warn("", e); } } finally { // The processor instance is only for fingerprinting so we can remove the InstanceClassLoader here // since otherwise it will stick around in the map forever if (processor != null) { ExtensionManager.removeInstanceClassLoaderIfExists(processor.getIdentifier()); } } // properties final NodeList propertyElems = DomUtils.getChildNodesByTagName(processorElem, "property"); final List<Element> sortedPropertyElems = sortElements(propertyElems, getProcessorPropertiesComparator()); for (final Element propertyElem : sortedPropertyElems) { final String propName = DomUtils.getChildElementsByTagName(propertyElem, "name").get(0) .getTextContent(); String propValue = getFirstValue(DomUtils.getChildNodesByTagName(propertyElem, "value"), null); addPropertyFingerprint(builder, processor, propName, propValue); } final NodeList autoTerminateElems = DomUtils.getChildNodesByTagName(processorElem, "autoTerminatedRelationship"); final List<Element> sortedAutoTerminateElems = sortElements(autoTerminateElems, getElementTextComparator()); for (final Element autoTerminateElem : sortedAutoTerminateElems) { builder.append(autoTerminateElem.getTextContent()); } return builder; } private StringBuilder addPropertyFingerprint(final StringBuilder builder, final ConfigurableComponent component, final String propName, final String propValue) throws FingerprintException { // If we have a component to use, first determine if the value given is the default value for the specified property. // If so, we do not add the property to the fingerprint. // We do this because if a component is updated to add a new property, whenever we connect to the cluster, we have issues because // the Cluster Coordinator's flow comes from disk, where the flow.xml doesn't have the new property but our FlowController does have the new property. // This causes the fingerprints not to match. As a result, we just ignore default values, and this resolves the issue. if (component != null) { final PropertyDescriptor descriptor = component.getPropertyDescriptor(propName); if (descriptor != null && propValue != null && propValue.equals(descriptor.getDefaultValue())) { return builder; } } // check if there is a value if (propValue == null) { return builder; } // append name builder.append(propName).append("="); // append value if (isEncrypted(propValue)) { // propValue is non null, no need to use getValue builder.append(decrypt(propValue)); } else { builder.append(getValue(propValue, NO_VALUE)); } return builder; } private StringBuilder addPortFingerprint(final StringBuilder builder, final Element portElem) throws FingerprintException { // id appendFirstValue(builder, DomUtils.getChildNodesByTagName(portElem, "id")); appendFirstValue(builder, DomUtils.getChildNodesByTagName(portElem, "name")); final NodeList userAccessControlNodeList = DomUtils.getChildNodesByTagName(portElem, "userAccessControl"); if (userAccessControlNodeList == null || userAccessControlNodeList.getLength() == 0) { builder.append("NO_USER_ACCESS_CONTROL"); } else { final List<String> sortedAccessControl = new ArrayList<>(); for (int i = 0; i < userAccessControlNodeList.getLength(); i++) { sortedAccessControl.add(userAccessControlNodeList.item(i).getTextContent()); } Collections.sort(sortedAccessControl); for (final String user : sortedAccessControl) { builder.append(user); } } final NodeList groupAccessControlNodeList = DomUtils.getChildNodesByTagName(portElem, "userAccessControl"); if (groupAccessControlNodeList == null || groupAccessControlNodeList.getLength() == 0) { builder.append("NO_GROUP_ACCESS_CONTROL"); } else { final List<String> sortedAccessControl = new ArrayList<>(); for (int i = 0; i < groupAccessControlNodeList.getLength(); i++) { sortedAccessControl.add(groupAccessControlNodeList.item(i).getTextContent()); } Collections.sort(sortedAccessControl); for (final String user : sortedAccessControl) { builder.append(user); } } return builder; } private StringBuilder addLabelFingerprint(final StringBuilder builder, final Element labelElem) { appendFirstValue(builder, DomUtils.getChildNodesByTagName(labelElem, "id")); appendFirstValue(builder, DomUtils.getChildNodesByTagName(labelElem, "value")); return builder; } private StringBuilder addRemoteProcessGroupFingerprint(final StringBuilder builder, final Element remoteProcessGroupElem) throws FingerprintException { for (String tagName : new String[] { "id", "urls", "networkInterface", "timeout", "yieldPeriod", "transportProtocol", "proxyHost", "proxyPort", "proxyUser", "proxyPassword" }) { final String value = getFirstValue(DomUtils.getChildNodesByTagName(remoteProcessGroupElem, tagName)); if (isEncrypted(value)) { builder.append(decrypt(value)); } else { builder.append(value); } } final NodeList inputPortList = DomUtils.getChildNodesByTagName(remoteProcessGroupElem, "inputPort"); final NodeList outputPortList = DomUtils.getChildNodesByTagName(remoteProcessGroupElem, "outputPort"); final Comparator<Element> portComparator = new Comparator<Element>() { @Override public int compare(final Element o1, final Element o2) { if (o1 == null && o2 == null) { return 0; } if (o1 == null) { return 1; } if (o2 == null) { return -1; } NodeList nameList1 = DomUtils.getChildNodesByTagName(o1, "name"); NodeList nameList2 = DomUtils.getChildNodesByTagName(o2, "name"); if (nameList1.getLength() == 0 && nameList2.getLength() == 0) { return 0; } if (nameList1.getLength() == 0) { return 1; } if (nameList2.getLength() == 0) { return -1; } return nameList1.item(0).getTextContent().compareTo(nameList2.item(0).getTextContent()); } }; final List<Element> sortedInputPorts = new ArrayList<>(inputPortList.getLength()); for (int i = 0; i < inputPortList.getLength(); i++) { sortedInputPorts.add((Element) inputPortList.item(i)); } Collections.sort(sortedInputPorts, portComparator); final List<Element> sortedOutputPorts = new ArrayList<>(outputPortList.getLength()); for (int i = 0; i < outputPortList.getLength(); i++) { sortedOutputPorts.add((Element) outputPortList.item(i)); } Collections.sort(sortedOutputPorts, portComparator); for (final Element inputPortElement : sortedInputPorts) { addRemoteGroupPortFingerprint(builder, inputPortElement); } for (final Element outputPortElement : sortedOutputPorts) { addRemoteGroupPortFingerprint(builder, outputPortElement); } return builder; } private StringBuilder addRemoteGroupPortFingerprint(final StringBuilder builder, final Element remoteGroupPortElement) { for (final String childName : new String[] { "id", "maxConcurrentTasks", "useCompression" }) { appendFirstValue(builder, DomUtils.getChildNodesByTagName(remoteGroupPortElement, childName)); } return builder; } private StringBuilder addConnectionFingerprint(final StringBuilder builder, final Element connectionElem) throws FingerprintException { // id appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "id")); // source id appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "sourceId")); // source group id appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "sourceGroupId")); // source type appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "sourceType")); // destination id appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "destinationId")); // destination group id appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "destinationGroupId")); // destination type appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "destinationType")); appendFirstValue(builder, DomUtils.getChildNodesByTagName(connectionElem, "name")); // relationships final NodeList relationshipElems = DomUtils.getChildNodesByTagName(connectionElem, "relationship"); final List<Element> sortedRelationshipElems = sortElements(relationshipElems, getConnectionRelationshipsComparator()); for (final Element relationshipElem : sortedRelationshipElems) { builder.append(getValue(relationshipElem, NO_VALUE)); } return builder; } private StringBuilder addFunnelFingerprint(final StringBuilder builder, final Element funnelElem) throws FingerprintException { // id appendFirstValue(builder, DomUtils.getChildNodesByTagName(funnelElem, "id")); return builder; } private void addControllerServiceFingerprint(final StringBuilder builder, final ControllerServiceDTO dto, final FlowController controller) { builder.append(dto.getId()); builder.append(dto.getType()); builder.append(dto.getName()); builder.append(dto.getComments()); builder.append(dto.getAnnotationData()); builder.append(dto.getState()); // create an instance of the ControllerService so that we know the default property values ControllerService controllerService = null; try { if (controller != null) { controllerService = controller .createControllerService(dto.getType(), UUID.randomUUID().toString(), false) .getControllerServiceImplementation(); } } catch (Exception e) { logger.warn( "Unable to create ControllerService of type {} due to {}; its default properties will be fingerprinted instead of being ignored.", dto.getType(), e.toString()); if (logger.isDebugEnabled()) { logger.warn("", e); } } addPropertiesFingerprint(builder, controllerService, dto.getProperties()); } private void addPropertiesFingerprint(final StringBuilder builder, final ConfigurableComponent component, final Map<String, String> properties) { if (properties == null) { builder.append("NO_PROPERTIES"); } else { final SortedMap<String, String> sortedProps = new TreeMap<>(properties); for (final Map.Entry<String, String> entry : sortedProps.entrySet()) { addPropertyFingerprint(builder, component, entry.getKey(), entry.getValue()); } } } private void addReportingTaskFingerprint(final StringBuilder builder, final ReportingTaskDTO dto, final FlowController controller) { builder.append(dto.getId()); builder.append(dto.getType()); builder.append(dto.getName()); builder.append(dto.getComments()); builder.append(dto.getSchedulingPeriod()); builder.append(dto.getSchedulingStrategy()); builder.append(dto.getAnnotationData()); // create an instance of the ReportingTask so that we know the default property values ReportingTask reportingTask = null; try { if (controller != null) { reportingTask = controller .createReportingTask(dto.getType(), UUID.randomUUID().toString(), false, false) .getReportingTask(); } } catch (Exception e) { logger.warn( "Unable to create ReportingTask of type {} due to {}; its default properties will be fingerprinted instead of being ignored.", dto.getType(), e.toString()); if (logger.isDebugEnabled()) { logger.warn("", e); } } addPropertiesFingerprint(builder, reportingTask, dto.getProperties()); } private Comparator<Element> getIdsComparator() { return new Comparator<Element>() { @Override public int compare(final Element e1, final Element e2) { // compare using processor ids final String e1Id = getFirstValue(DomUtils.getChildNodesByTagName(e1, "id")); final String e2Id = getFirstValue(DomUtils.getChildNodesByTagName(e2, "id")); return e1Id.compareTo(e2Id); } }; } private Comparator<Element> getProcessorPropertiesComparator() { return new Comparator<Element>() { @Override public int compare(final Element e1, final Element e2) { // combine the property name and value for the first required property final String e1PropName = getFirstValue(DomUtils.getChildNodesByTagName(e1, "name")); String e1PropValue = getFirstValue(DomUtils.getChildNodesByTagName(e1, "value")); if (isEncrypted(e1PropValue)) { e1PropValue = decrypt(e1PropValue); } final String e1CombinedValue = e1PropName + e1PropValue; // combine the property name and value for the second required property final String e2PropName = getFirstValue(DomUtils.getChildNodesByTagName(e2, "name")); String e2PropValue = getFirstValue(DomUtils.getChildNodesByTagName(e2, "value")); if (isEncrypted(e2PropValue)) { e2PropValue = decrypt(e2PropValue); } final String e2CombinedValue = e2PropName + e2PropValue; // compare the combined values return e1CombinedValue.compareTo(e2CombinedValue); } }; } private Comparator<Element> getConnectionRelationshipsComparator() { return getSingleChildComparator("relationship"); } private Comparator<Element> getSingleChildComparator(final String childElementName) { return new Comparator<Element>() { @Override public int compare(final Element e1, final Element e2) { if (e2 == null) { return -1; } else if (e1 == null) { return 1; } // compare using processor ids final String e1Id = getFirstValue(DomUtils.getChildNodesByTagName(e1, childElementName)); if (e1Id == null) { return 1; } final String e2Id = getFirstValue(DomUtils.getChildNodesByTagName(e2, childElementName)); if (e2Id == null) { return -1; } return e1Id.compareTo(e2Id); } }; } private Comparator<Element> getElementTextComparator() { return new Comparator<Element>() { @Override public int compare(final Element e1, final Element e2) { if (e2 == null) { return -1; } else if (e1 == null) { return 1; } return e1.getTextContent().compareTo(e2.getTextContent()); } }; } private List<Element> sortElements(final NodeList nodeList, final Comparator<Element> comparator) { final List<Element> result = new ArrayList<>(); // add node list to sorted list for (int i = 0; i < nodeList.getLength(); i++) { result.add((Element) nodeList.item(i)); } Collections.sort(result, comparator); return result; } private String getValue(final Node node) { return getValue(node, NO_VALUE); } private String getValue(final Node node, final String defaultValue) { final String value; if (node.getTextContent() == null || StringUtils.isBlank(node.getTextContent())) { value = defaultValue; } else { value = node.getTextContent().trim(); } return value; } private String getValue(final String value, final String defaultValue) { if (StringUtils.isBlank(value)) { return defaultValue; } else { return value; } } private String getFirstValue(final NodeList nodeList) { return getFirstValue(nodeList, NO_VALUE); } private String getFirstValue(final NodeList nodeList, final String defaultValue) { final String value; if (nodeList == null || nodeList.getLength() == 0) { value = defaultValue; } else { value = getValue(nodeList.item(0)); } return value; } private StringBuilder appendFirstValue(final StringBuilder builder, final NodeList nodeList) { return appendFirstValue(builder, nodeList, NO_VALUE); } private StringBuilder appendFirstValue(final StringBuilder builder, final NodeList nodeList, final String defaultValue) { return builder.append(getFirstValue(nodeList, defaultValue)); } private boolean isEncrypted(final String value) { return (value.startsWith(ENCRYPTED_VALUE_PREFIX) && value.endsWith(ENCRYPTED_VALUE_SUFFIX)); } private String decrypt(final String value) throws FingerprintException { final int decryptStartIdx = ENCRYPTED_VALUE_PREFIX.length(); final int decryptEndIdx = value.length() - ENCRYPTED_VALUE_SUFFIX.length(); return encryptor.decrypt(value.substring(decryptStartIdx, decryptEndIdx)); } }