Yuta HIGUCHI | b34078e | 2017-08-17 12:06:02 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2017-present Open Networking Foundation |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | package org.onlab.util; |
| 17 | |
| 18 | import java.io.IOException; |
| 19 | import java.io.StringWriter; |
| 20 | |
| 21 | import javax.xml.parsers.DocumentBuilderFactory; |
| 22 | import javax.xml.transform.OutputKeys; |
| 23 | import javax.xml.transform.Transformer; |
| 24 | import javax.xml.transform.TransformerFactory; |
| 25 | import javax.xml.transform.dom.DOMSource; |
| 26 | import javax.xml.transform.stream.StreamResult; |
| 27 | import javax.xml.xpath.XPath; |
| 28 | import javax.xml.xpath.XPathConstants; |
| 29 | import javax.xml.xpath.XPathFactory; |
| 30 | |
| 31 | import org.slf4j.Logger; |
| 32 | import org.slf4j.LoggerFactory; |
| 33 | import org.w3c.dom.Document; |
| 34 | import org.w3c.dom.Node; |
| 35 | import org.w3c.dom.NodeList; |
| 36 | import org.xml.sax.InputSource; |
| 37 | import com.google.common.base.Supplier; |
| 38 | import com.google.common.base.Suppliers; |
| 39 | import com.google.common.io.CharSource; |
| 40 | |
| 41 | /** |
| 42 | * PrettyPrinted XML String. |
| 43 | */ |
| 44 | public class XmlString implements CharSequence { |
| 45 | |
| 46 | private static final Logger log = LoggerFactory.getLogger(XmlString.class); |
| 47 | |
| 48 | private final Supplier<String> prettyString; |
| 49 | |
| 50 | |
| 51 | /** |
| 52 | * Prettifies given XML String. |
| 53 | * |
| 54 | * @param xml input XML |
| 55 | * @return prettified input or input itself is input is not well-formed |
| 56 | */ |
| 57 | public static CharSequence prettifyXml(CharSequence xml) { |
| 58 | return new XmlString(CharSource.wrap(xml)); |
| 59 | } |
| 60 | |
| 61 | XmlString(CharSource inputXml) { |
| 62 | prettyString = Suppliers.memoize(() -> prettyPrintXml(inputXml)); |
| 63 | } |
| 64 | |
| 65 | private String prettyPrintXml(CharSource inputXml) { |
| 66 | try { |
| 67 | Document document = DocumentBuilderFactory.newInstance() |
| 68 | .newDocumentBuilder() |
| 69 | .parse(new InputSource(inputXml.openStream())); |
| 70 | |
| 71 | document.normalize(); |
| 72 | |
| 73 | XPath xPath = XPathFactory.newInstance().newXPath(); |
| 74 | NodeList nodeList = (NodeList) xPath.evaluate("//text()[normalize-space()='']", |
| 75 | document, |
| 76 | XPathConstants.NODESET); |
| 77 | |
| 78 | for (int i = 0; i < nodeList.getLength(); ++i) { |
| 79 | Node node = nodeList.item(i); |
| 80 | node.getParentNode().removeChild(node); |
| 81 | } |
| 82 | |
| 83 | // Setup pretty print options |
| 84 | Transformer t = TransformerFactory.newInstance().newTransformer(); |
| 85 | t.setOutputProperty(OutputKeys.ENCODING, "UTF-8"); |
| 86 | t.setOutputProperty(OutputKeys.OMIT_XML_DECLARATION, "yes"); |
| 87 | t.setOutputProperty(OutputKeys.INDENT, "yes"); |
| 88 | t.setOutputProperty("{http://xml.apache.org/xslt}indent-amount", "2"); |
| 89 | |
| 90 | // Return pretty print xml string |
| 91 | StringWriter strWriter = new StringWriter(); |
| 92 | t.transform(new DOMSource(document), new StreamResult(strWriter)); |
| 93 | return strWriter.toString(); |
| 94 | } catch (Exception e) { |
| 95 | log.warn("Pretty printing failed", e); |
| 96 | try { |
| 97 | String rawInput = inputXml.read(); |
| 98 | log.debug(" failed input: \n{}", rawInput); |
| 99 | return rawInput; |
| 100 | } catch (IOException e1) { |
| 101 | log.error("Failed to read from input", e1); |
| 102 | return inputXml.toString(); |
| 103 | } |
| 104 | } |
| 105 | } |
| 106 | |
| 107 | @Override |
| 108 | public int length() { |
| 109 | return toString().length(); |
| 110 | } |
| 111 | |
| 112 | @Override |
| 113 | public char charAt(int index) { |
| 114 | return toString().charAt(index); |
| 115 | } |
| 116 | |
| 117 | @Override |
| 118 | public CharSequence subSequence(int start, int end) { |
| 119 | return toString().subSequence(start, end); |
| 120 | } |
| 121 | |
| 122 | @Override |
| 123 | public String toString() { |
| 124 | return prettyString.get(); |
| 125 | } |
| 126 | |
| 127 | } |