2 * Copyright (c) 2015 Cisco Systems, Inc. and others. All rights reserved.
4 * This program and the accompanying materials are made available under the
5 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
6 * and is available at http://www.eclipse.org/legal/epl-v10.html
8 package org.opendaylight.netconf.api.xml;
10 import static javax.xml.XMLConstants.XMLNS_ATTRIBUTE;
11 import static javax.xml.XMLConstants.XMLNS_ATTRIBUTE_NS_URI;
13 import com.google.common.io.Resources;
14 import java.io.ByteArrayInputStream;
16 import java.io.FileInputStream;
17 import java.io.IOException;
18 import java.io.InputStream;
19 import java.io.StringWriter;
20 import java.nio.charset.StandardCharsets;
21 import java.util.Optional;
22 import javax.xml.namespace.QName;
23 import javax.xml.parsers.DocumentBuilder;
24 import javax.xml.parsers.DocumentBuilderFactory;
25 import javax.xml.parsers.ParserConfigurationException;
26 import javax.xml.transform.OutputKeys;
27 import javax.xml.transform.Templates;
28 import javax.xml.transform.Transformer;
29 import javax.xml.transform.TransformerConfigurationException;
30 import javax.xml.transform.TransformerException;
31 import javax.xml.transform.TransformerFactory;
32 import javax.xml.transform.dom.DOMSource;
33 import javax.xml.transform.stream.StreamResult;
34 import javax.xml.transform.stream.StreamSource;
35 import javax.xml.xpath.XPathExpression;
36 import javax.xml.xpath.XPathExpressionException;
37 import org.w3c.dom.Document;
38 import org.w3c.dom.Element;
39 import org.w3c.dom.Node;
40 import org.xml.sax.SAXException;
42 public final class XmlUtil {
44 * A pre-compiled XSL template to deal with Java XML transform creating empty lines when indenting is enabled, as
45 * detailed in <a href="https://bugs.openjdk.org/browse/JDK-8262285">JDK-8262285</a>.
47 private static final Templates PRETTY_PRINT_TEMPLATE;
51 PRETTY_PRINT_TEMPLATE = TransformerFactory.newInstance()
52 .newTemplates(new StreamSource(Resources.getResource(XmlUtil.class, "/pretty-print.xsl").openStream()));
53 } catch (IOException | TransformerConfigurationException e) {
54 throw new ExceptionInInitializerError(e);
58 private static final DocumentBuilderFactory BUILDER_FACTORY;
61 DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
63 factory.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
64 factory.setFeature("http://xml.org/sax/features/external-general-entities", false);
65 factory.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
66 factory.setXIncludeAware(false);
67 factory.setExpandEntityReferences(false);
68 // Performance improvement for messages with size <10k according to
69 // https://xerces.apache.org/xerces2-j/faq-performance.html
70 factory.setFeature("http://apache.org/xml/features/dom/defer-node-expansion", false);
71 } catch (final ParserConfigurationException e) {
72 throw new ExceptionInInitializerError(e);
74 factory.setNamespaceAware(true);
75 factory.setCoalescing(true);
76 factory.setIgnoringElementContentWhitespace(true);
77 factory.setIgnoringComments(true);
78 BUILDER_FACTORY = factory;
81 private static final ThreadLocal<DocumentBuilder> DEFAULT_DOM_BUILDER = new ThreadLocal<>() {
83 protected DocumentBuilder initialValue() {
85 return BUILDER_FACTORY.newDocumentBuilder();
86 } catch (final ParserConfigurationException e) {
87 throw new IllegalStateException("Failed to create threadLocal dom builder", e);
92 public void set(final DocumentBuilder value) {
93 throw new UnsupportedOperationException();
101 public static Element readXmlToElement(final File xmlFile) throws SAXException, IOException {
102 return readXmlToDocument(new FileInputStream(xmlFile)).getDocumentElement();
105 public static Element readXmlToElement(final String xmlContent) throws SAXException, IOException {
106 Document doc = readXmlToDocument(xmlContent);
107 return doc.getDocumentElement();
110 public static Element readXmlToElement(final InputStream xmlContent) throws SAXException, IOException {
111 Document doc = readXmlToDocument(xmlContent);
112 return doc.getDocumentElement();
115 public static Document readXmlToDocument(final String xmlContent) throws SAXException, IOException {
116 return readXmlToDocument(new ByteArrayInputStream(xmlContent.getBytes(StandardCharsets.UTF_8)));
119 // TODO improve exceptions throwing
120 // along with XmlElement
122 public static Document readXmlToDocument(final InputStream xmlContent) throws SAXException, IOException {
123 Document doc = DEFAULT_DOM_BUILDER.get().parse(xmlContent);
125 doc.getDocumentElement().normalize();
129 public static Document newDocument() {
130 return DEFAULT_DOM_BUILDER.get().newDocument();
133 public static Element createElement(final Document document, final String qname,
134 final Optional<String> namespaceURI) {
135 if (namespaceURI.isEmpty()) {
136 return document.createElement(qname);
139 final String uri = namespaceURI.orElseThrow();
140 final Element element = document.createElementNS(uri, qname);
141 String name = XMLNS_ATTRIBUTE;
142 if (element.getPrefix() != null) {
143 name += ":" + element.getPrefix();
145 element.setAttributeNS(XMLNS_ATTRIBUTE_NS_URI, name, uri);
149 public static Element createTextElement(final Document document, final String qname, final String content,
150 final Optional<String> namespaceURI) {
151 Element typeElement = createElement(document, qname, namespaceURI);
152 typeElement.appendChild(document.createTextNode(content));
156 public static Element createTextElementWithNamespacedContent(final Document document, final String qname,
157 final String prefix, final String namespace, final String contentWithoutPrefix) {
159 return createTextElementWithNamespacedContent(document, qname, prefix, namespace, contentWithoutPrefix,
163 public static Element createTextElementWithNamespacedContent(final Document document, final String qname,
164 final String prefix, final String namespace, final String contentWithoutPrefix,
165 final Optional<String> namespaceURI) {
167 String content = createPrefixedValue(XmlNetconfConstants.PREFIX, contentWithoutPrefix);
168 Element element = createTextElement(document, qname, content, namespaceURI);
169 String prefixedNamespaceAttr = createPrefixedValue(XMLNS_ATTRIBUTE, prefix);
170 element.setAttributeNS(XMLNS_ATTRIBUTE_NS_URI, prefixedNamespaceAttr, namespace);
174 public static String createPrefixedValue(final String prefix, final String value) {
175 return prefix + ":" + value;
179 * Return a new {@link Transformer} which performs indentation.
181 * @return A new Transformer
182 * @throws TransformerConfigurationException if a Transformer can not be created
184 public static Transformer newIndentingTransformer() throws TransformerConfigurationException {
185 final Transformer ret = PRETTY_PRINT_TEMPLATE.newTransformer();
186 ret.setOutputProperty(OutputKeys.INDENT, "yes");
190 public static String toString(final Document document) {
191 return toString(document.getDocumentElement());
194 public static String toString(final Element xml) {
195 return toString(xml, false);
198 public static String toString(final XmlElement xmlElement) {
199 return toString(xmlElement.getDomElement(), false);
202 public static String toString(final Element xml, final boolean addXmlDeclaration) {
203 final StringWriter writer = new StringWriter();
206 Transformer transformer = newIndentingTransformer();
207 transformer.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, addXmlDeclaration ? "no" : "yes");
208 transformer.transform(new DOMSource(xml), new StreamResult(writer));
209 } catch (TransformerException e) {
210 throw new IllegalStateException("Unable to serialize xml element " + xml, e);
213 return writer.toString();
216 public static String toString(final Document doc, final boolean addXmlDeclaration) {
217 return toString(doc.getDocumentElement(), addXmlDeclaration);
220 public static Object evaluateXPath(final XPathExpression expr, final Object rootNode, final QName returnType) {
222 return expr.evaluate(rootNode, returnType);
223 } catch (final XPathExpressionException e) {
224 throw new IllegalStateException("Error while evaluating xpath expression " + expr, e);
228 public static Document createDocumentCopy(final Document original) {
229 final Document copiedDocument = newDocument();
230 final Node copiedRoot = copiedDocument.importNode(original.getDocumentElement(), true);
231 copiedDocument.appendChild(copiedRoot);
232 return copiedDocument;