- Sams Teach Yourself XML in 21 Days, Third Edition
- Table of Contents
- About the Author
- Acknowledgments
- We Want to Hear from You!
- Introduction
- Part I: At a Glance
- Day 1. Welcome to XML
- All About Markup Languages
- All About XML
- Looking at XML in a Browser
- Working with XML Data Yourself
- Structuring Your Data
- Creating Well-Formed XML Documents
- Creating Valid XML Documents
- How XML Is Used in the Real World
- Online XML Resources
- Summary
- Q&A
- Workshop
- Day 2. Creating XML Documents
- Choosing an XML Editor
- Using XML Browsers
- Using XML Validators
- Creating XML Documents Piece by Piece
- Creating Prologs
- Creating an XML Declaration
- Creating XML Comments
- Creating Processing Instructions
- Creating Tags and Elements
- Creating CDATA Sections
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 3. Creating Well-Formed XML Documents
- What Makes an XML Document Well-Formed?
- Creating an Example XML Document
- Understanding the Well-Formedness Constraints
- Using XML Namespaces
- Understanding XML Infosets
- Understanding Canonical XML
- Summary
- Q&A
- Workshop
- Day 4. Creating Valid XML Documents: DTDs
- All About DTDs
- Validating a Document by Using a DTD
- Creating Element Content Models
- Commenting a DTD
- Supporting External DTDs
- Handling Namespaces in DTDs
- Summary
- Q&A
- Workshop
- Declaring Attributes in DTDs
- Day 5. Handling Attributes and Entities in DTDs
- Specifying Default Values
- Specifying Attribute Types
- Handling Entities
- Summary
- Q&A
- Workshop
- Day 6. Creating Valid XML Documents: XML Schemas
- Using XML Schema Tools
- Creating XML Schemas
- Dissecting an XML Schema
- The Built-in XML Schema Elements
- Creating Elements and Types
- Specifying a Number of Elements
- Specifying Element Default Values
- Creating Attributes
- Summary
- Q&A
- Workshop
- Day 7. Creating Types in XML Schemas
- Restricting Simple Types by Using XML Schema Facets
- Creating XML Schema Choices
- Using Anonymous Type Definitions
- Declaring Empty Elements
- Declaring Mixed-Content Elements
- Grouping Elements Together
- Grouping Attributes Together
- Declaring all Groups
- Handling Namespaces in Schemas
- Annotating an XML Schema
- Summary
- Q&A
- Workshop
- Part I. In Review
- Well-Formed Documents
- Valid Documents
- Part II: At a Glance
- Day 8. Formatting XML by Using Cascading Style Sheets
- Our Sample XML Document
- Introducing CSS
- Connecting CSS Style Sheets and XML Documents
- Creating Style Sheet Selectors
- Using Inline Styles
- Creating Style Rule Specifications in Style Sheets
- Summary
- Q&A
- Workshop
- Day 9. Formatting XML by Using XSLT
- Introducing XSLT
- Transforming XML by Using XSLT
- Writing XSLT Style Sheets
- Using <xsl:apply-templates>
- Using <xsl:value-of> and <xsl:for-each>
- Matching Nodes by Using the match Attribute
- Working with the select Attribute and XPath
- Using <xsl:copy>
- Using <xsl:if>
- Using <xsl:choose>
- Specifying the Output Document Type
- Summary
- Q&A
- Workshop
- Day 10. Working with XSL Formatting Objects
- Introducing XSL-FO
- Using XSL-FO
- Using XSL Formatting Objects and Properties
- Building an XSL-FO Document
- Handling Inline Formatting
- Formatting Lists
- Formatting Tables
- Summary
- Q&A
- Workshop
- Part II. In Review
- Using CSS
- Using XSLT
- Using XSL-FO
- Part III: At a Glance
- Day 11. Extending HTML with XHTML
- Why XHTML?
- Writing XHTML Documents
- Validating XHTML Documents
- The Basic XHTML Elements
- Organizing Text
- Formatting Text
- Selecting Fonts: <font>
- Comments: <!-->
- Summary
- Q&A
- Workshop
- Day 12. Putting XHTML to Work
- Creating Hyperlinks: <a>
- Linking to Other Documents: <link>
- Handling Images: <img>
- Creating Frame Documents: <frameset>
- Creating Frames: <frame>
- Creating Embedded Style Sheets: <style>
- Formatting Tables: <table>
- Creating Table Rows: <tr>
- Formatting Table Headers: <th>
- Formatting Table Data: <td>
- Extending XHTML
- Summary
- Q&A
- Workshop
- Day 13. Creating Graphics and Multimedia: SVG and SMIL
- Introducing SVG
- Creating an SVG Document
- Creating Rectangles
- Adobe's SVG Viewer
- Using CSS Styles
- Creating Circles
- Creating Ellipses
- Creating Lines
- Creating Polylines
- Creating Polygons
- Creating Text
- Creating Gradients
- Creating Paths
- Creating Text Paths
- Creating Groups and Transformations
- Creating Animation
- Creating Links
- Creating Scripts
- Embedding SVG in HTML
- Introducing SMIL
- Summary
- Q&A
- Workshop
- Day 14. Handling XLinks, XPointers, and XForms
- Introducing XLinks
- Beyond Simple XLinks
- Introducing XPointers
- Introducing XBase
- Introducing XForms
- Summary
- Workshop
- Part III. In Review
- Part IV: At a Glance
- Day 15. Using JavaScript and XML
- Introducing the W3C DOM
- Introducing the DOM Objects
- Working with the XML DOM in JavaScript
- Searching for Elements by Name
- Reading Attribute Values
- Getting All XML Data from a Document
- Validating XML Documents by Using DTDs
- Summary
- Q&A
- Workshop
- Day 16. Using Java and .NET: DOM
- Using Java to Read XML Data
- Finding Elements by Name
- Creating an XML Browser by Using Java
- Navigating Through XML Documents
- Writing XML by Using Java
- Summary
- Q&A
- Workshop
- Day 17. Using Java and .NET: SAX
- An Overview of SAX
- Using SAX
- Using SAX to Find Elements by Name
- Creating an XML Browser by Using Java and SAX
- Navigating Through XML Documents by Using SAX
- Writing XML by Using Java and SAX
- Summary
- Q&A
- Workshop
- Day 18. Working with SOAP and RDF
- Introducing SOAP
- A SOAP Example in .NET
- A SOAP Example in Java
- Introducing RDF
- Summary
- Q&A
- Workshop
- Part IV. In Review
- Part V: At a Glance
- Day 19. Handling XML Data Binding
- Introducing DSOs
- Binding HTML Elements to HTML Data
- Binding HTML Elements to XML Data
- Binding HTML Tables to XML Data
- Accessing Individual Data Fields
- Binding HTML Elements to XML Data by Using the XML DSO
- Binding HTML Tables to XML Data by Using the XML DSO
- Searching XML Data by Using a DSO and JavaScript
- Handling Hierarchical XML Data
- Summary
- Q&A
- Workshop
- Day 20. Working with XML and Databases
- XML, Databases, and ASP
- Storing Databases as XML
- Using XPath with a Database
- Introducing XQuery
- Summary
- Q&A
- Workshop
- Day 21. Handling XML in .NET
- Creating and Editing an XML Document in .NET
- From XML to Databases and Back
- Reading and Writing XML in .NET Code
- Using XML Controls to Display Formatted XML
- Creating XML Web Services
- Summary
- Q&A
- Workshop
- Part V. In Review
- Appendix A. Quiz Answers
- Quiz Answers for Day 1
- Quiz Answers for Day 2
- Quiz Answers for Day 3
- Quiz Answers for Day 4
- Quiz Answers for Day 5
- Quiz Answers for Day 6
- Quiz Answers for Day 7
- Quiz Answers for Day 8
- Quiz Answers for Day 9
- Quiz Answers for Day 10
- Quiz Answers for Day 11
- Quiz Answers for Day 12
- Quiz Answers for Day 13
- Quiz Answers for Day 14
- Quiz Answers for Day 15
- Quiz Answers for Day 16
- Quiz Answers for Day 17
- Quiz Answers for Day 18
- Quiz Answers for Day 19
- Quiz Answers for Day 20
- Quiz Answers for Day 21
Creating an XML Browser by Using Java
Besides letting us work with text, Java also lets us work with graphics. You'll take advantage of that to create a complete XML browser in Java now, using the relatively simple Java Abstract Windowing Toolkit (AWT).
In this example, you're going to read in the XML document shown in Listing 16.4. This document uses a <square> element to draw squares in an XML browser. The upper left of each square is set by the <square> element's x and y attributes as the point (x,y), and the width of each square is set by the width attribute.
Example 16.4. An XML Document for an XML Browser (ch16_04.xml)
<?xml version = "1.0" encoding="UTF-8"?> <!DOCTYPE document [ <!ELEMENT document (square)*> <!ELEMENT square EMPTY> <!ATTLIST square x CDATA #IMPLIED y CDATA #IMPLIED width CDATA #IMPLIED> ]> <document> <square x='220' y='130' width='50' /> <square x='140' y='180' width='15' /> <square x='60' y='100' width='45' /> <square x='210' y='190' width='35' /> <square x='20' y='200' width='25' /> <square x='260' y='280' width='45' /> <square x='220' y='220' width='25' /> <square x='90' y='180' width='35' /> <square x='140' y='290' width='55' /> </document>
In your Java code, you need to read in the new XML document, ch16_04.xml, and interpret it. You'll store the total number of squares to draw in a variable named totalFigures, the x values of the squares in an array named x, the y values of the squares in an array named y, and the widths of the squares in an array named width:
import java.awt.*; import java.awt.event.*; import javax.xml.parsers.*; import org.w3c.dom.*; public class ch16_05 { static int totalFigures = 0; static int x[] = new int[100]; static int y[] = new int[100]; static int width[] = new int[100]; . . .
In the main method, you'll read in the document and call the childLoop method to decode the data in the XML document:
import java.awt.*; import java.awt.event.*; import javax.xml.parsers.*; import org.w3c.dom.*; public class ch16_05 { static int totalFigures = 0; static int x[] = new int[100]; static int y[] = new int[100]; static int width[] = new int[100]; public static void main(String args[]) { try { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = null; try { builder = factory.newDocumentBuilder(); } catch (ParserConfigurationException e) {} Document document = null; document = builder.parse(args[0]); childLoop(document); } catch (Exception e) { e.printStackTrace(System.err); } . . .
After the childLoop method fills the totalFigures variable and the x, y, and width arrays, you can use code in the main method to pass those items to a new Java class, AppFrame, based on the Java Frame class, to create the window and display the data:
AppFrame frame = new AppFrame(totalFigures, x, y, width); frame.setSize(400, 400); frame.addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e) {System.exit(0);}}); frame.show(); }
Here's what the AppFrame class, which just uses the Java drawRect method to draw the squares in your new window, looks like:
class AppFrame extends Frame { int totalFigures; int[] xValues; int[] yValues; int[] widthValues; public AppFrame(int number, int[] x, int[] y, int[] width) { totalFigures = number; xValues = x; yValues = y; widthValues = width; } public void paint(Graphics g) { for(int loopIndex = 0; loopIndex < totalFigures; loopIndex++){ g.drawRect(xValues[loopIndex], yValues[loopIndex], widthValues[loopIndex], widthValues[loopIndex]); } } }
All that's left is to write the childLoop method that does that actual decoding of the data and fills the totalFigures variable and the x, y, and width arrays. In this method, you'll look for <square> element nodes and decipher their x, y, and width attributes. To do that, you use the getAttributes method to get a named node map of each <square> element's attributes and then use the getNamedItem method to recover the attributes you want. Here's what the childLoop method looks like:
public static void childLoop(Node node) { if (node == null) { return; } int type = node.getNodeType(); if (node.getNodeType() == Node.DOCUMENT_NODE) { childLoop(((Document)node).getDocumentElement()); } if (node.getNodeType() == Node.ELEMENT_NODE) { if (node.getNodeName().equals("square")) { NamedNodeMap attrs = node.getAttributes(); x[totalFigures] = Integer.parseInt((String)attrs.getNamedItem("x"). getNodeValue()); y[totalFigures] = Integer.parseInt((String)attrs.getNamedItem("y"). getNodeValue()); width[totalFigures] = Integer.parseInt((String)attrs.getNamedItem("width"). getNodeValue()); totalFigures++; } NodeList childNodes = node.getChildNodes(); if (childNodes != null) { int length = childNodes.getLength(); for (int loopIndex = 0; loopIndex < length; loopIndex++) { childLoop(childNodes.item(loopIndex)) ; } } } }
Figure 16.3 shows the results. As the figure shows, the code has indeed read in the XML document ch16_04.xml, interpreted it, and displayed the results. Now you've created an XML browser from scratch, using Java. Listing 16.5 shows all the code for it.
Example 16.5. An XML Browser (ch16_05.java)
import java.awt.*; import java.awt.event.*; import javax.xml.parsers.*; import org.w3c.dom.*; public class ch16_05 { static int totalFigures = 0; static int x[] = new int[100]; static int y[] = new int[100]; static int width[] = new int[100]; public static void main(String args[]) { try { DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance(); DocumentBuilder builder = null; try { builder = factory.newDocumentBuilder(); } catch (ParserConfigurationException e) {} Document document = null; document = builder.parse(args[0]); childLoop(document) ; } catch (Exception e) { e.printStackTrace(System.err); } AppFrame frame = new AppFrame(totalFigures, x, y, width); frame.setSize(400, 400); frame.addWindowListener(new WindowAdapter() {public void windowClosing(WindowEvent e) {System.exit(0);}}); frame.show(); } public static void childLoop(Node node) { if (node == null) { return; } int type = node.getNodeType(); if (node.getNodeType() == Node.DOCUMENT_NODE) { childLoop(((Document)node).getDocumentElement()); } if (node.getNodeType() == Node.ELEMENT_NODE) { if (node.getNodeName().equals("square")) { NamedNodeMap attrs = node.getAttributes(); x[totalFigures] = Integer.parseInt((String) attrs.getNamedItem("x").getNodeValue()); y[totalFigures] = Integer.parseInt((String) attrs.getNamedItem("y").getNodeValue()); width[totalFigures] = Integer.parseInt((String) attrs.getNamedItem("width").getNodeValue()); totalFigures++; } NodeList childNodes = node.getChildNodes(); if (childNodes != null) { int length = childNodes.getLength(); for (int loopIndex = 0; loopIndex < length; loopIndex++) { childLoop(childNodes.item(loopIndex)); } } } } } class AppFrame extends Frame { int totalFigures; int[] xValues; int[] yValues; int[] widthValues; public AppFrame(int number, int[] x, int[] y, int[] width) { totalFigures = number; xValues = x; yValues = y; widthValues = width; } public void paint(Graphics g) { for(int loopIndex = 0; loopIndex < totalFigures; loopIndex++){ g.drawRect(xValues[loopIndex], yValues[loopIndex], widthValues[loopIndex], widthValues[loopIndex]); } } }

Figure 16.3 Creating an XML browser.