| 1 | /* This file is part of the project "Hilbert II" - http://www.qedeq.org |
| 2 | * |
| 3 | * Copyright 2000-2014, Michael Meyling <mime@qedeq.org>. |
| 4 | * |
| 5 | * "Hilbert II" is free software; you can redistribute |
| 6 | * it and/or modify it under the terms of the GNU General Public |
| 7 | * License as published by the Free Software Foundation; either |
| 8 | * version 2 of the License, or (at your option) any later version. |
| 9 | * |
| 10 | * This program is distributed in the hope that it will be useful, |
| 11 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 13 | * GNU General Public License for more details. |
| 14 | */ |
| 15 | |
| 16 | package org.qedeq.kernel.xml.parser; |
| 17 | |
| 18 | import java.io.BufferedReader; |
| 19 | import java.io.IOException; |
| 20 | import java.io.Reader; |
| 21 | |
| 22 | import javax.xml.parsers.ParserConfigurationException; |
| 23 | import javax.xml.parsers.SAXParser; |
| 24 | import javax.xml.parsers.SAXParserFactory; |
| 25 | |
| 26 | import org.qedeq.base.io.IoUtility; |
| 27 | import org.qedeq.base.trace.Trace; |
| 28 | import org.qedeq.kernel.se.base.list.Element; |
| 29 | import org.qedeq.kernel.se.common.ModuleService; |
| 30 | import org.qedeq.kernel.se.common.SourceFileExceptionList; |
| 31 | import org.qedeq.kernel.xml.handler.common.SaxDefaultHandler; |
| 32 | import org.qedeq.kernel.xml.handler.list.BasicHandler; |
| 33 | import org.xml.sax.InputSource; |
| 34 | import org.xml.sax.SAXException; |
| 35 | import org.xml.sax.XMLReader; |
| 36 | |
| 37 | /** |
| 38 | * Parse {@link Element}s. |
| 39 | * |
| 40 | * @author Michael Meyling |
| 41 | * |
| 42 | */ |
| 43 | public final class BasicParser { |
| 44 | |
| 45 | /** This class. */ |
| 46 | private static final Class CLASS = BasicParser.class; |
| 47 | |
| 48 | /** Here we handle the events. */ |
| 49 | private SaxDefaultHandler handler; |
| 50 | |
| 51 | /** XML reader. */ |
| 52 | private XMLReader reader; |
| 53 | |
| 54 | /** Here we describe this "plugin". */ |
| 55 | private static ModuleService plugin = new ModuleService() { |
| 56 | public String getServiceDescription() { |
| 57 | return "parses element lists and atoms"; |
| 58 | } |
| 59 | public String getServiceId() { |
| 60 | return BasicParser.class.getName(); |
| 61 | } |
| 62 | public String getServiceAction() { |
| 63 | return "element parser"; |
| 64 | } |
| 65 | }; |
| 66 | |
| 67 | |
| 68 | /** |
| 69 | * Constructor. |
| 70 | * |
| 71 | * @param handler Default handler for this application. |
| 72 | * @throws ParserConfigurationException Severe parser configuration problem. |
| 73 | * @throws SAXException Parse problems. |
| 74 | */ |
| 75 | private BasicParser(final SaxDefaultHandler handler) |
| 76 | throws ParserConfigurationException, SAXException { |
| 77 | super(); |
| 78 | this.handler = handler; |
| 79 | final String factoryImpl = System.getProperty("javax.xml.parsers.SAXParserFactory"); |
| 80 | if (factoryImpl == null) { |
| 81 | System.setProperty("javax.xml.parsers.SAXParserFactory", |
| 82 | "org.apache.xerces.jaxp.SAXParserFactoryImpl"); |
| 83 | } |
| 84 | SAXParserFactory factory = SAXParserFactory.newInstance(); |
| 85 | factory.setNamespaceAware(false); |
| 86 | factory.setValidating(false); |
| 87 | |
| 88 | final SAXParser parser = factory.newSAXParser(); |
| 89 | reader = parser.getXMLReader(); |
| 90 | } |
| 91 | |
| 92 | /** |
| 93 | * Parse input source. |
| 94 | * |
| 95 | * @param url Source URL. Only for information. |
| 96 | * @param in Parse data from this source. |
| 97 | * @throws SAXException Syntactical or semantical problem occurred. |
| 98 | * @throws IOException Technical problem occurred. |
| 99 | */ |
| 100 | private void parse(final String url, final Reader in) |
| 101 | throws IOException, SAXException { |
| 102 | final String method = "parse(URL, boolean, InputStream)"; |
| 103 | BufferedReader dis = null; |
| 104 | SourceFileExceptionList exceptionList = new SourceFileExceptionList();; |
| 105 | try { |
| 106 | dis = new BufferedReader(in); |
| 107 | final InputSource input = new InputSource(dis); |
| 108 | reader.setErrorHandler(new SaxErrorHandler(plugin, |
| 109 | url, exceptionList)); |
| 110 | handler.setExceptionList(exceptionList); |
| 111 | reader.setContentHandler(handler); |
| 112 | handler.setUrl(url); |
| 113 | reader.parse(input); |
| 114 | } finally { |
| 115 | if (dis != null) { |
| 116 | try { |
| 117 | dis.close(); |
| 118 | } catch (Exception e) { |
| 119 | Trace.trace(CLASS, this, method, e); |
| 120 | } |
| 121 | } |
| 122 | } |
| 123 | } |
| 124 | |
| 125 | /** |
| 126 | * Create elements out of XML string. |
| 127 | * |
| 128 | * @param xml XML document part. XML header not necessary. |
| 129 | * @return Created elements. |
| 130 | * @throws ParserConfigurationException Problem configuring parser. |
| 131 | * @throws SAXException Parsing problem. |
| 132 | */ |
| 133 | public static final Element[] createElements(final String xml) |
| 134 | throws ParserConfigurationException, SAXException { |
| 135 | try { |
| 136 | String data = "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\n" |
| 137 | + "<basic>\n" |
| 138 | + xml + "\n" |
| 139 | + "</basic>\n"; |
| 140 | SaxDefaultHandler handler = new SaxDefaultHandler(plugin); |
| 141 | BasicHandler simple = new BasicHandler(handler); |
| 142 | handler.setBasisDocumentHandler(simple); |
| 143 | BasicParser parser = new BasicParser(handler); |
| 144 | parser.parse("memory", IoUtility.stringToReader(data)); |
| 145 | return (Element[]) simple.getElements().toArray(new Element[]{}); |
| 146 | } catch (SAXException e) { |
| 147 | Trace.trace(BasicParser.class, "createElement", e); |
| 148 | Trace.trace(BasicParser.class, "createElement", e.getCause()); |
| 149 | throw e; |
| 150 | } catch (IOException e) { |
| 151 | Trace.trace(BasicParser.class, "createElement", e); |
| 152 | // should not happen, hej we are parsing a String! |
| 153 | throw new RuntimeException(e); |
| 154 | } |
| 155 | } |
| 156 | |
| 157 | /** |
| 158 | * Create element out of XML string. |
| 159 | * |
| 160 | * @param xml XML document part. XML header not necessary. |
| 161 | * @return Created element. |
| 162 | * @throws ParserConfigurationException Problem configuring parser. |
| 163 | * @throws SAXException Parsing problem. |
| 164 | */ |
| 165 | public static final Element createElement(final String xml) |
| 166 | throws ParserConfigurationException, SAXException { |
| 167 | final Element[] elements = createElements(xml); |
| 168 | if (elements == null || elements.length == 0) { |
| 169 | return null; |
| 170 | } |
| 171 | return elements[0]; |
| 172 | } |
| 173 | |
| 174 | } |