Java & XML resources (updated)

• Tutorialspoint
• XML Schema Definition (xsd)
• W3C Data Types
• Complex Types
• Netbeans
• Schema Editor plugin
• XPath plugin 
• start from Window>XPath
• Notepad++ XML tools plugin
• validation
• XSL
• XPath
• More XML tools 
• JAXP project
• JAXP 1.3 (Java 5) validator package javadoc

JAXB custom conversion using @XmlJavaTypeAdapter

To provide your own conversion implementation of a JAXB property, annotate the property in your JAXB class with javax.xml.bind.annotation.adapters.@XmlJavaTypeAdapter:

    @XmlJavaTypeAdapter(MyAdapter.class)
    public void setFrom(LocalDate from) {
        this.from = from;
    }
 
Then write your Adapter marshalling your LocalDate attribute to an XML value String and unmarshalling it:

    public class MyDateAdapter extends XmlAdapter<String, LocalDate> {
    public LocalDate unmarshal(String myString) throws Exception {
      return LocalDate.parse(myString);
    }

    public String marshal(LocalDate myDate) throws Exception {
      return myDate.toString();
    }
  }

New DOM modules by Level (updated)

The W3C DOM specification is partitioned in a set of modules
Release versions of the DOM specification by W3C are called levels.
The table below shows which new modules appeared in each Level. Each higher level contains all modules of previous  levels.
Note: DOM Level 2 also introduces namespaces.

Level 1	Level 2	Level 3
Core	XML	Xpath
HTML	Views	Validation
	Range	Load and Save
	Traversal	Asynchronous Load
	Stylesheets	Mutation Name Events
	CSS	UI Events
	CSS2	Text Events
	Events	Keyboard Events
	User Interface Events
	Mouse Events
	Mutation Events
	HTML Events

Modules can be optional and can have different W3C recommendation statusses. You can check if your implementation supports a module using DOMImplementation.hasFeature(module, level) or Node.isSupported(feature, version) . Append ".0" to the level number (e.g. "3.0" for Level 3). Use null or empty string if any level will do.

Setting the JAXP validation file (updated)

A JAXP parser validates (version >= 1.2) by default using a DTD. Here are some variations that can be used when validating

• If you are using SAX and obtained this parser from the SAXParserFactory:

javax.xml.parsers.SAXParser parser

• To validated using a schema (xsd) add this line of code to your parser setup:

parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaLanguage", 

  XMLConstants.W3C_XML_SCHEMA_NS_URI); 

• To specify the schema file in your code (for both DTD and XSD) add this line to your parser setup:

parser.setProperty("http://java.sun.com/xml/jaxp/properties/schemaSource", 

  new File("checkers.xsd")); 

              SL-385.B: add to code 3-2 after line 17   

• The source can be a File, InputStream, InputSource or an Object array containing these types

• If you are using DOM, and you created this DocumentBuilderFactory instance :
  

javax.xml.parsers.DocumentBuilderFactory builder

• To validated using a schema (xsd) add this line of code to your parser setup:

builder.setAttribute("http://java.sun.com/xml/jaxp/properties/schemaLanguage", 

  XMLConstants.W3C_XML_SCHEMA_NS_URI);

• XMLConstants.W3C_XML_SCHEMA_NS_URI = http://www.w3.org/2001/XMLSchema

The corresponding constant for DTD (the default) in these cases is  

• XMLConstants.XML_DTD_NS_URI = http://www.w3.org/TR/REC-xml

• To specify the schema file in your code (for both DTD and XSD) add this line to your parser setup:

builder.setAttribute("http://java.sun.com/xml/jaxp/properties/schemaSource", 

  new File("checkers.xsd")); 

JAXP history (updated)

Java SE	JAXP	What’s new
		DOM level 0: javascript in NS/IE v3
	1.0	DOM level 1 (tree), SAX 1.0 (push) org.xml.sax.Parser
1.4	1.1	DOM Level 2, SAX 2.0 (+validation), TrAX (XSLT) Apache Crimson XMLReader
	1.2	XML Schema Apache Xerces2 XMLReader
5	1.3	DOM level 3, XML 1.1, XInclude 1.0, Xpath 1, Validator API
6	1.4	StAX (pull) SE also bundles JAXB
7u40	1.5
8	1.6
9	-	no separate JAXP anymore, moved into Java SE

More details on DOM levels.

XML versus JSON

• Advantages of XML: document markup
• XML schema
• namespaces
• strong widespread validation
• data type reuse
• references
• mixed content, CDATA
• comments
• XPath querying
• Advantages of JSON: data interchange
• concise format
• JavaScript subset, builtin parser
• arrays

DOM XML Load validation

The example below adds DOM schema validation when you are parsing the XML input file to the DOM load/save example.
The example also features a DOM Level 3 DOMErrorHandler.
Also compare with the editing validation example.

// SimpleDOML3XSD.java

import org.w3c.dom.*;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.*;

import javax.xml.XMLConstants;
import java.io.OutputStreamWriter;

public class SimpleDOML3LSXSD {

  public static void main(String args[]) {
    Document doc;
    try {

      // Create DOM Document using DOM Level 3 Load
      DOMImplementationLS ls = (DOMImplementationLS) DOMImplementationRegistry.
        newInstance().getDOMImplementation("LS");
      LSParser builder = ls.createLSParser(
        DOMImplementationLS.MODE_SYNCHRONOUS,
        // for DTD use XMLConstants.XML_DTD_NS_URI
        XMLConstants.W3C_XML_SCHEMA_NS_URI);
      DOMConfiguration config = builder.getDomConfig();
      config.setParameter("validate", true);
      config.setParameter("error-handler", new StdErrorHandler());
      doc = builder.parseURI(args[0]);

      // Obtain root elements
      Element root = doc.getDocumentElement();

      // Add comment texts
      Comment comment = doc.createComment("Training text");
      root.appendChild(comment);

      // Output to standard output; using DOM Level 3 save
      LSOutput target = ls.createLSOutput();
      target.setCharacterStream(new OutputStreamWriter(System.out));
      ls.createLSSerializer().write(doc, target);

    } catch (Exception e) {
      System.out.println(e.getMessage());
      e.printStackTrace();
      System.exit(0);
    }
  }

  private static class StdErrorHandler implements DOMErrorHandler {

    public boolean handleError(DOMError e) {
      String prefix = "Severity ";
      if (e.getLocation().getLineNumber() != -1) {
         prefix = "Line " + e.getLocation().getLineNumber()
          + " column  " + e.getLocation().getColumnNumber()
          + ", severity ";
      }
      System.err.println(
        prefix + e.getSeverity()
          + " issue: " + e.getMessage());
      return true;
    }
  }
}

Load and Save XML with DOM (Level 3)

Prior to DOM Level 3, DOM did not standardize reading and writing XML.
Below is the  SL-385 code 4-2 modified to use the standard DOM level 3 Load and Save (LS) API.
An alternative JAXP (but not DOM standard) way is to read using the JAXP DocumentBuilder and to write using the JAXP transformer (TrAX XSLT).
(I included a comment showing DOM LS writing starting from a DocumentBuilder obrained from JAXP reading as well.)

// SimpleDOML3LS.java
import org.w3c.dom.*;
import org.w3c.dom.bootstrap.DOMImplementationRegistry;
import org.w3c.dom.ls.*;
import java.io.OutputStreamWriter;

public class SimpleDOML3LS {

  public static void main(String args[]) {
    Document doc;
    try {

      // Create DOM Document using DOM Level 3 Load 
      DOMImplementationLS ls = (DOMImplementationLS) DOMImplementationRegistry.
          newInstance().getDOMImplementation("LS");
      LSParser builder = ls.createLSParser(
        DOMImplementationLS.MODE_SYNCHRONOUS,
        null);
      doc = builder.parseURI(args[0]);

      // Obtain root elements
      Element root = doc.getDocumentElement();

      // Add comment texts
      Comment comment = doc.createComment("Training text");
      root.appendChild(comment);

      // Output to standard output; using DOM Level 3 save

      // If you parsed using a JAXP DocumentBuilder
      // you can also get your LSimplementation from your Document:
      // DOMImplementationLS ls = (DOMImplementationLS) doc.
      //   getImplementation().getFeature("LS","3.0");
      LSOutput target = ls.createLSOutput();
      target.setCharacterStream(new OutputStreamWriter(System.out));
      ls.createLSSerializer().write(doc, target);

    } catch (Exception e) {
      System.out.println(e.getMessage());
      e.printStackTrace();
      System.exit(0);
    }
  }
}

To add newlines/indents to enhance readability of the output, replace in the above example

ls.createLSSerializer().write(doc, target);

with

      LSSerializer serializer = ls.createLSSerializer();
      DOMConfiguration serializerConfig = serializer.getDomConfig();
      serializerConfig.setParameter("format-pretty-print", Boolean.TRUE);
      serializer.write(doc, target);