Tools to simplify XML serialization

1. XML Magic упрощаем сериализацию E-mail: khotin@gmx.com Игорь Хотинь

3. 6+ лет с Java

6. public class CodeSource { List<CustomError> errorList = new ArrayList<CustomError>(); public CodeSource() { // fill the error list CustomError error = new CustomError(); error.setCode(101); error.setMessage( &quot;Is there an error in this code?&quot; ); errorList .add(error); // create the source Source source = new Source(); source.setProblem(101); // raise an error source.error( errorList ); } }

7. public class CustomError { private int code ; private String message ; public String toString() { return &quot;Error #&quot; + code + &quot;: &quot; + message ; } public int getCode() { return this . code ; } public void setCode( int code) { this . code = code; } public void setMessage(String message) { this . message = message; } }

8. public class Source { private int problem ; public void setProblem( int problem) { this . problem = problem; } public void error(List<CustomError> errorList) { for (CustomError e: errorList) { if (e.getCode() == this . problem ) { System. err .println(e); return ; } } System. err .println( &quot;Error: error not found&quot; ); } }

10. Data-driven approach

11. XML

13. Доступные средства парсинга и верификации

14. Self-describing (в определённой степени)

15. Human-readable (в определённой степени)

16. Сложный, многословный, перегруженный

17. Алтернатива: JSON, YAML, SDL...

18. XML в нашей индустрии: всерьёз и надолго

19. < config > < handler > < error > < code > 101 </ code > < message > Not our fault </ message > </ error > < error > < code > 102 </ code > < message > Keyboard not found... press F1 to continue </ message > </ error > < error > < code > 103 </ code > < message > Reserved for future mistakes by our developers </ message > </ error > </ handler > < source > < problem > 102 </ problem > </ source > </ config >

21. Лёгкий для понимания

22. Минимум кода, быстрая реализация

23. Гибкий

25. Максимум скорости

26. Минимум памяти

27. Сложность в обработке сложных структур

28. Read-only

29. List<CustomError> errorList = new ArrayList<CustomError>(); Source source = new Source(); public SaxSource(InputStream input) { try { SAXParserFactory factory = SAXParserFactory. newInstance (); SAXParser saxParser = factory.newSAXParser(); saxParser.parse(input, this ); source .error( errorList ); } catch (Throwable e) { e.printStackTrace(); } }

30. String tempVal ; CustomError tempError ; public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException { tempVal = &quot;&quot; ; if (qName.equalsIgnoreCase( &quot;error&quot; )) { tempError = new CustomError(); } } public void characters( char [] ch, int start, int length) throws SAXException { tempVal += new String(ch, start, length); } public void endElement(String uri, String localName, String qName) throws SAXException { if (qName.equalsIgnoreCase( &quot;error&quot; )) { errorList .add( tempError ); } else if (qName.equalsIgnoreCase( &quot;message&quot; )) { tempError .setMessage( tempVal ); } else if (qName.equalsIgnoreCase( &quot;code&quot; )) { tempError .setCode(Integer. parseInt ( tempVal .trim())); } else if (qName.equalsIgnoreCase( &quot;problem&quot; )) { source .setProblem(Integer. parseInt ( tempVal .trim())); } }

32. XML-дерево

33. Ресурсоёмко

34. Boilerplate-код

35. No Java-feel

36. List<CustomError> errorList = new ArrayList<CustomError>(); Source source = new Source(); public DomSource(InputStream input) { try { DocumentBuilderFactory dbf = DocumentBuilderFactory. newInstance (); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(input); Element root = doc.getDocumentElement(); NodeList nl = root.getElementsByTagName( &quot;handler&quot; ); if (nl != null && nl.getLength() > 0) { Element e = (Element)nl.item(0); NodeList errList = e.getElementsByTagName( &quot;error&quot; ); for ( int i = 0; i < errList.getLength(); i++) { CustomError error = new CustomError(); Element el = (Element)errList.item(i); if (el == null ) continue ; NodeList clist = el.getElementsByTagName( &quot;code&quot; ); if (clist != null && clist.getLength() > 0) { error.setCode(Integer. parseInt ( clist.item(0).getTextContent())); } NodeList mlist = el.getElementsByTagName( &quot;message&quot; ); if (mlist != null && mlist.getLength() > 0) { error.setMessage(mlist.item(0).getTextContent()); } this . errorList .add(error); } } дурDOM

37. nl = root.getElementsByTagName( &quot;source&quot; ); if (nl != null && nl.getLength() > 0) { Element src = (Element)nl.item(0); NodeList plist = src.getElementsByTagName( &quot;problem&quot; ); if (plist != null && plist.getLength() > 0) { this . source .setProblem(Integer. parseInt (plist.item(0) .getTextContent())); } } XMLSerializer serializer = new XMLSerializer(); serializer.setOutputCharStream( new java.io.FileWriter( &quot;out.xml&quot; )); serializer.serialize(doc); } catch (Exception e) { e.printStackTrace(); } source .error( errorList ); }

39. Ресурсоёмко

40. Boilerplate-код

41. No Java-feel

42. List<CustomError> errorList = new ArrayList<CustomError>(); Source source = new Source(); public XPathSource(InputStream input) { try { XPath xpath = XPathFactory. newInstance ().newXPath(); DocumentBuilderFactory dbf = DocumentBuilderFactory. newInstance (); DocumentBuilder db = dbf.newDocumentBuilder(); Document doc = db.parse(input); Element root = doc.getDocumentElement(); NodeList nl = (NodeList)xpath.evaluate( &quot;handler/error/code/text()&quot; , root, XPathConstants. NODESET ); for ( int i = 0; i < nl.getLength(); i++) { CustomError error = new CustomError(); error.setCode(Integer. parseInt (nl.item(i).getTextContent())); errorList .add(error); } nl = (NodeList)xpath.evaluate( &quot;handler/error/message/text()&quot; , root, XPathConstants. NODESET ); for ( int i = 0; i < nl.getLength(); i++) { errorList .get(i).setMessage(nl.item(i).getTextContent()); } Double problem = (Double)xpath.evaluate( &quot;source/problem&quot; , root, XPathConstants. NUMBER ); source .setProblem(problem.intValue()); source .error( errorList ); } catch (Exception e) { e.printStackTrace(); } }

44. Интеграция с SAX и DOM

45. Поддерживает XPath и XSLT

46. Заброшенный JSR 102

47. Меньше Boilerplate, чем DOM

48. Java-feel API

49. List<CustomError> errorList = new ArrayList<CustomError>(); Source source = new Source(); public JdomSource(InputStream input) { try { SAXBuilder builder = new SAXBuilder(); Document doc = builder.build(input); Element root = doc.getRootElement(); Element handler = root.getChild( &quot;handler&quot; ); List elist = handler.getChildren( &quot;error&quot; ); for (Object obj: elist) { CustomError error = new CustomError(); Element err = (Element)obj; error.setCode(Integer. parseInt (err.getChildTextTrim( &quot;code&quot; ))); error.setMessage(err.getChildText( &quot;message&quot; )); errorList .add(error); } Element source = root.getChild( &quot;source&quot; ); this . source .setProblem( Integer. parseInt (source.getChildTextTrim( &quot;problem&quot; ))); XMLOutputter outp = new XMLOutputter(); outp.output(doc, new FileOutputStream( &quot;jdom.xml&quot; )); } catch (Exception e) { e.printStackTrace(); } source .error( errorList ); }

51. XStream?

52. JAXB (JSR 222)?

53. Apache XMLBeans?

54. JiBX?

55. Hibernate 3 XML Mapping(!) ?

56. ...

57. Apache Digester

59. Rule-based parsing engine

60. В основе – стек

62. Присваивает объектам свойства

63. Связывает их друг с другом

64. List<CustomError> errorList = new ArrayList<CustomError>(); Source source = new Source(); public DigesterSource(InputStream input) { try { Digester digester = new Digester(); digester.addObjectCreate( &quot;config/handler/error&quot; , CustomError. class ); digester.addBeanPropertySetter( &quot;config/handler/error/code&quot; , &quot;code&quot; ); digester.addBeanPropertySetter( &quot;config/handler/error/message&quot; , &quot;message&quot; ); digester.addSetNext( &quot;config/handler/error&quot; , &quot;addError&quot; ); digester.addObjectCreate( &quot;config/source&quot; , Source. class ); digester.addBeanPropertySetter( &quot;config/source/problem&quot; , &quot;problem&quot; ); digester.addSetNext( &quot;config/source&quot; , &quot;setSource&quot; ); digester.push( this ); digester.parse(input); this . source .error( this . errorList ); } catch (Exception e) { e.printStackTrace(); } } public void addError(CustomError error) { this . errorList .add(error); } public void setSource(Source source) { this . source = source; }

66. Reflection – влияет на производительность

67. Read-only

69. FactoryCreateRule

70. SetPropertiesRule

71. SetNextRule

72. CallMethodRule

74. XML and @nnotation конфигурации

77. Простой фреймворк с широкими возможностями

78. Zero-configuration

79. Rapid Development

80. Human-readable XML

81. public SimpleSource(InputStream input) { try { Serializer serializer = new Persister(); Config config = (Config)serializer .read(Config. class , input); config.error(); serializer.write( config, new File(&quot;simple.xml&quot;)); } catch (Exception e) { e.printStackTrace(); } }

82. @Root (name= &quot;config&quot; ) public class Config { @ElementList (name= &quot;handler&quot; ) private List<CustomError> list ; @Element private Source source ; public void error() { this . source .error( list ); } }

83. public class CustomError { @Element private int code ; @Element private String message ; public String toString() { return &quot;Error #&quot; + code + &quot;: &quot; + message ; } public int getCode() { return this . code ; } public void setCode( int code) { this . code = code; } public void setMessage(String message) { this . message = message; } }

84. public class Source { @Element private int problem ; public void setProblem( int problem) { this . problem = problem; } public void error(List<CustomError> errorList) { for (CustomError e: errorList) { if (e.getCode() == this . problem ) { System. err .println(e); return ; } } System. err .println( &quot;Error: error not found&quot; ); } }

86. @Element

88. Замечательный туториал

90. Конвертеры для ручной сериализации

91. Маппинг XPath выражений

92. Поддержка версионности

93. А что выбираешь ты?

96. commons.apache.org/digester

97. www.jdom.org

98. www.w3.org/DOM

99. www.w3.org/TR/xpath

100. Контакты E-mail: [email_address] Blog: www.ikhotin.com Twitter: chaostarter linkedin .com/pub/igor-khotin/5/193/257