cc.xml
Class PrettyPrinter

java.lang.Object
  org.xml.sax.helpers.DefaultHandler
      cc.xml.PrettyPrinter

All Implemented Interfaces:

org.xml.sax.ContentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler

public class PrettyPrinter
extends org.xml.sax.helpers.DefaultHandler

This class "pretty prints" an XML stream to something more human-readable. It duplicates the character content with some modifications to whitespace, restoring line breaks and a simple pattern of indenting child elements. This version of the class acts as a SAX 2.0 DefaultHandler, so to provide the unformatted XML just pass a new instance to a SAX parser. Its output is via the toString method. One major limitation: we gather character data for elements in a single buffer, so mixed-content documents will lose a lot of data! This works best with data-centric documents where elements either have single values or child elements, but not both.

Nested Class Summary

static class

PrettyPrinter.StreamAdapter

Field Summary

private java.lang.StringBuffer	currentValue A buffer for character data.
private static java.lang.String	endLine
private java.lang.String	indent This whitespace string is expanded and collapsed to manage the output indenting.
private boolean	justHitStartTag
private java.lang.StringBuffer	output The primary buffer for accumulating the formatted XML.
private static java.lang.String	standardIndent

Constructor Summary

PrettyPrinter()

Method Summary

void	characters(char[] chars, int start, int length) When the currentValue buffer is enabled, appends character data into it, to be gathered when the element end tag is encountered.
void	endDocument() Prints a blank line at the end of the reformatted document.
void	endElement(java.lang.String URI, java.lang.String name, java.lang.String qName) Checks the currentValue buffer to gather element content.
private static java.lang.String	escape(char[] chars, int start, int length) Filter to pass strings to output, escaping < and & characters to &lt; and &amp; respectively.
static java.lang.String	prettyPrint(byte[] content) Convenience method to wrap pretty-printing SAX pass over existing content.
static java.lang.String	prettyPrint(org.w3c.dom.Document doc) Convenience method to wrap pretty-printing SAX pass over existing content.
static java.lang.String	prettyPrint(java.io.InputStream content) Convenience method to wrap pretty-printing SAX pass over existing content.
static java.lang.String	prettyPrint(java.lang.String content) Convenience method to wrap pretty-printing SAX pass over existing content.
void	startDocument() Prints the XML declaration.
void	startElement(java.lang.String URI, java.lang.String name, java.lang.String qName, org.xml.sax.Attributes attributes) Writes the start tag for the element.
java.lang.String	toString() Call this to get the formatted XML post-parsing.

Methods inherited from class org.xml.sax.helpers.DefaultHandler

endPrefixMapping, error, fatalError, ignorableWhitespace, notationDecl, processingInstruction, resolveEntity, setDocumentLocator, skippedEntity, startPrefixMapping, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

indent

private java.lang.String indent

This whitespace string is expanded and collapsed to manage the output indenting.

currentValue

private java.lang.StringBuffer currentValue

A buffer for character data. It is "enabled" in startElement by being initialized to a new StringBuffer, and then read and reset to null in endElement.

output

private java.lang.StringBuffer output

The primary buffer for accumulating the formatted XML.

justHitStartTag

private boolean justHitStartTag

standardIndent

private static final java.lang.String standardIndent

See Also:

Constant Field Values

endLine

private static final java.lang.String endLine

Constructor Detail

PrettyPrinter

public PrettyPrinter()

Method Detail

prettyPrint

public static java.lang.String prettyPrint(byte[] content)

Convenience method to wrap pretty-printing SAX pass over existing content.

prettyPrint

public static java.lang.String prettyPrint(java.lang.String content)

Convenience method to wrap pretty-printing SAX pass over existing content.

prettyPrint

public static java.lang.String prettyPrint(java.io.InputStream content)

Convenience method to wrap pretty-printing SAX pass over existing content.

prettyPrint

public static java.lang.String prettyPrint(org.w3c.dom.Document doc)
                                    throws javax.xml.transform.TransformerException

Convenience method to wrap pretty-printing SAX pass over existing content.

Throws:

javax.xml.transform.TransformerException

toString

public java.lang.String toString()

Call this to get the formatted XML post-parsing.

Overrides:

toString in class java.lang.Object

startDocument

public void startDocument()
                   throws org.xml.sax.SAXException

Prints the XML declaration.

Specified by:

startDocument in interface org.xml.sax.ContentHandler

Overrides:

startDocument in class org.xml.sax.helpers.DefaultHandler

Throws:

org.xml.sax.SAXException

endDocument

public void endDocument()
                 throws org.xml.sax.SAXException

Prints a blank line at the end of the reformatted document.

Specified by:

endDocument in interface org.xml.sax.ContentHandler

Overrides:

endDocument in class org.xml.sax.helpers.DefaultHandler

Throws:

org.xml.sax.SAXException

startElement

public void startElement(java.lang.String URI,
                         java.lang.String name,
                         java.lang.String qName,
                         org.xml.sax.Attributes attributes)
                  throws org.xml.sax.SAXException

Writes the start tag for the element. Attributes are written out, one to a text line. Starts gathering character data for the element.

Specified by:

startElement in interface org.xml.sax.ContentHandler

Overrides:

startElement in class org.xml.sax.helpers.DefaultHandler

Throws:

org.xml.sax.SAXException

endElement

public void endElement(java.lang.String URI,
                       java.lang.String name,
                       java.lang.String qName)
                throws org.xml.sax.SAXException

Checks the currentValue buffer to gather element content. Writes this out if it is available. Writes the element end tag.

Specified by:

endElement in interface org.xml.sax.ContentHandler

Overrides:

endElement in class org.xml.sax.helpers.DefaultHandler

Throws:

org.xml.sax.SAXException

characters

public void characters(char[] chars,
                       int start,
                       int length)
                throws org.xml.sax.SAXException

When the currentValue buffer is enabled, appends character data into it, to be gathered when the element end tag is encountered.

Specified by:

characters in interface org.xml.sax.ContentHandler

Overrides:

characters in class org.xml.sax.helpers.DefaultHandler

Throws:

org.xml.sax.SAXException

escape

private static java.lang.String escape(char[] chars,
                                       int start,
                                       int length)

Filter to pass strings to output, escaping < and & characters to &lt; and &amp; respectively.