| /* |
| * Copyright 2017-present Open Networking Foundation |
| * |
| * 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 |
| * |
| * 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.onlab.util; |
| |
| import java.io.IOException; |
| import java.io.StringWriter; |
| |
| import javax.xml.parsers.DocumentBuilder; |
| import javax.xml.parsers.DocumentBuilderFactory; |
| import javax.xml.transform.OutputKeys; |
| import javax.xml.transform.Transformer; |
| import javax.xml.transform.TransformerFactory; |
| import javax.xml.transform.dom.DOMSource; |
| import javax.xml.transform.stream.StreamResult; |
| import javax.xml.xpath.XPath; |
| import javax.xml.xpath.XPathConstants; |
| import javax.xml.xpath.XPathFactory; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| 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 org.xml.sax.helpers.DefaultHandler; |
| |
| import com.google.common.base.Supplier; |
| import com.google.common.base.Suppliers; |
| import com.google.common.io.CharSource; |
| |
| /** |
| * PrettyPrinted XML String. |
| */ |
| public class XmlString implements CharSequence { |
| |
| private static final Logger log = LoggerFactory.getLogger(XmlString.class); |
| |
| private final Supplier<String> prettyString; |
| |
| |
| /** |
| * Prettifies given XML String. |
| * |
| * @param xml input XML |
| * @return prettified input or input itself is input is not well-formed |
| */ |
| public static CharSequence prettifyXml(CharSequence xml) { |
| return new XmlString(CharSource.wrap(xml)); |
| } |
| |
| XmlString(CharSource inputXml) { |
| prettyString = Suppliers.memoize(() -> prettyPrintXml(inputXml)); |
| } |
| |
| private String prettyPrintXml(CharSource inputXml) { |
| try { |
| Document document; |
| boolean wasFragment = false; |
| |
| DocumentBuilder docBuilder = DocumentBuilderFactory.newInstance() |
| .newDocumentBuilder(); |
| // do not print error to stderr |
| docBuilder.setErrorHandler(new DefaultHandler()); |
| |
| try { |
| document = docBuilder |
| .parse(new InputSource(inputXml.openStream())); |
| } catch (SAXException e) { |
| log.debug("will retry assuming input is XML fragment", e); |
| // attempt to parse XML fragments, adding virtual root |
| try { |
| document = docBuilder |
| .parse(new InputSource(CharSource.concat(CharSource.wrap("<vroot>"), |
| inputXml, |
| CharSource.wrap("</vroot>") |
| ).openStream())); |
| wasFragment = true; |
| } catch (SAXException e1) { |
| log.debug("SAXException after retry", e1); |
| // Probably wasn't fragment issue, throwing original |
| throw e; |
| } |
| } |
| |
| document.normalize(); |
| |
| XPath xPath = XPathFactory.newInstance().newXPath(); |
| NodeList nodeList = (NodeList) xPath.evaluate("//text()[normalize-space()='']", |
| document, |
| XPathConstants.NODESET); |
| |
| for (int i = 0; i < nodeList.getLength(); ++i) { |
| Node node = nodeList.item(i); |
| node.getParentNode().removeChild(node); |
| } |
| |
| // Setup pretty print options |
| Transformer t = TransformerFactory.newInstance().newTransformer(); |
| t.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); |
| t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes"); |
| t.setOutputProperty(OutputKeys.INDENT, "yes"); |
| t.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2"); |
| |
| // Return pretty print xml string |
| StringWriter strWriter = new StringWriter(); |
| if (wasFragment) { |
| // print everything but virtual root node added |
| NodeList children = document.getDocumentElement().getChildNodes(); |
| for (int i = 0; i < children.getLength(); ++i) { |
| t.transform(new DOMSource(children.item(i)), new StreamResult(strWriter)); |
| } |
| } else { |
| t.transform(new DOMSource(document), new StreamResult(strWriter)); |
| } |
| return strWriter.toString(); |
| } catch (Exception e) { |
| log.warn("Pretty printing failed", e); |
| try { |
| String rawInput = inputXml.read(); |
| log.debug(" failed input: \n{}", rawInput); |
| return rawInput; |
| } catch (IOException e1) { |
| log.error("Failed to read from input", e1); |
| return inputXml.toString(); |
| } |
| } |
| } |
| |
| @Override |
| public int length() { |
| return toString().length(); |
| } |
| |
| @Override |
| public char charAt(int index) { |
| return toString().charAt(index); |
| } |
| |
| @Override |
| public CharSequence subSequence(int start, int end) { |
| return toString().subSequence(start, end); |
| } |
| |
| @Override |
| public String toString() { |
| return prettyString.get(); |
| } |
| |
| } |