com.deltaxml.pipe.filters

Class NormalizeSpace

java.lang.Object

org.xml.sax.helpers.XMLFilterImpl

com.deltaxml.pipe.XMLFilterImpl2

com.deltaxml.pipe.filters.NormalizeSpace

All Implemented Interfaces:

org.xml.sax.ContentHandler, org.xml.sax.DTDHandler, org.xml.sax.EntityResolver, org.xml.sax.ErrorHandler, org.xml.sax.ext.DeclHandler, org.xml.sax.ext.LexicalHandler, org.xml.sax.XMLFilter, org.xml.sax.XMLReader

public final class NormalizeSpace
extends XMLFilterImpl2

Removes whitespace in PCDATA and attributes in an XML file. Whitespace is defined as:

• multiple space characters (#x20 hex)
• tab characters (#x9 hex or \t escaped Java character)
• newline (linefeed) characters (#xA hex or \n escaped Java character)
• carriage returns (#xD hex or \r escaped Java character)

Unlike the standard definition of the XSLT normalize-space function, leading and trailing whitespace in PCDATA nodes is replaced by a single space, and not removed altogether. This is due to the possible need to output as html or xhtml.

To preserve whitespace in a specific section of the XML file, the xml:space attribute should be included in an element and set to preserve. This attribute applies to a complete subtree beneath that element unless overridden by another xml:space attribute at a lower level.
WARNING: We have found this attribute to successfully preserve space with the Saxon processor, but not with Xalan-J. Therefore we strongly recommend the use of Saxon when any input data uses xml:space attributes.

By default, whitespace between elements is removed. In the following example, the space between the bold and italic words would be deleted: <para>some text <bold>bold words</bold> <italic>italic words</italic></para> To change this behaviour, adding the attribute deltaxml:mixed-content="true" to the paragraph level causes the whitespace to be normalised rather than removed. N.B. This attribute needs to be added at every level that it is required, it is not inherited from parent elements.

NormalizeSpace should be used as the first filter in a pipeline to ensure that subsequent filters do not regard whitespace as significant. It should be applied to either both input files or neither of them. Applying it to a single input file may have an undesired effect.

Note: This class has not been designed to be extended, therefore to err on the side of caution, it has been declared final.

Constructor Summary

Constructors

Constructor and Description
NormalizeSpace() Creates a new instance of NormalizeSpace.

Method Summary

Modifier and Type	Method and Description
void	characters(char[] ch, int start, int length) Overrides the default characters method.
void	elementDecl(java.lang.String name, java.lang.String model) Overrides the default elementDecl method.
void	endElement(java.lang.String uri, java.lang.String localName, java.lang.String qName) Overrides the default endElement method.
void	ignorableWhitespace(char[] ch, int start, int length) Overrides the default ignorableWhitespace method.
void	setnormalizeAttValues(java.lang.String value) Specifies whether to normalize attribute values.
void	startDocument() Overrides the default startDocument method.
void	startElement(java.lang.String uri, java.lang.String localName, java.lang.String qName, org.xml.sax.Attributes atts) Overrides the default startElement method.
void	startPrefixMapping(java.lang.String prefix, java.lang.String uri) Overrides the default startPrefixMapping method.

Methods inherited from class com.deltaxml.pipe.XMLFilterImpl2

attributeDecl, comment, endCDATA, endDTD, endEntity, externalEntityDecl, getProperty, internalEntityDecl, parse, parse, setProperty, startCDATA, startDTD, startEntity

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

endDocument, endPrefixMapping, error, fatalError, getContentHandler, getDTDHandler, getEntityResolver, getErrorHandler, getFeature, getParent, notationDecl, processingInstruction, resolveEntity, setContentHandler, setDocumentLocator, setDTDHandler, setEntityResolver, setErrorHandler, setFeature, setParent, skippedEntity, unparsedEntityDecl, warning

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

NormalizeSpace

public NormalizeSpace()

Creates a new instance of NormalizeSpace. An instance cannot be shared amongst pipelines, it can only receive SAX event inputs from a single source and send events to a single output, thus two instances of this class are typically required when used in conjunction with the DeltaXML XMLComparator.

Method Detail

setnormalizeAttValues

public void setnormalizeAttValues(java.lang.String value)

Specifies whether to normalize attribute values.

Parameters:

value - whether to normalize attribute values

elementDecl

public void elementDecl(java.lang.String name,
                        java.lang.String model)
                 throws org.xml.sax.SAXException

Overrides the default elementDecl method.

Specified by:

elementDecl in interface org.xml.sax.ext.DeclHandler

Overrides:

elementDecl in class XMLFilterImpl2

Parameters:

name - - the element type name

model - - the content model as a normalized string

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing

See Also:

DeclHandler.elementDecl(String, String)

startPrefixMapping

public void startPrefixMapping(java.lang.String prefix,
                               java.lang.String uri)
                        throws org.xml.sax.SAXException

Overrides the default startPrefixMapping method.

Specified by:

startPrefixMapping in interface org.xml.sax.ContentHandler

Overrides:

startPrefixMapping in class org.xml.sax.helpers.XMLFilterImpl

Parameters:

prefix - - the namespace prefix

uri - - the namespace URI

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing.

See Also:

XMLFilterImpl.startPrefixMapping(String, String)

startDocument

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

Overrides the default startDocument method. This method performs internal operations.

Specified by:

startDocument in interface org.xml.sax.ContentHandler

Overrides:

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

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing.

startElement

public void startElement(java.lang.String uri,
                         java.lang.String localName,
                         java.lang.String qName,
                         org.xml.sax.Attributes atts)
                  throws org.xml.sax.SAXException

Overrides the default startElement method. This method performs internal operations.

Specified by:

startElement in interface org.xml.sax.ContentHandler

Overrides:

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

Parameters:

uri - - the element's namespace URI

localName - - the element's localname

qName - - the element's qualified name

atts - - the element's attributes

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing.

See Also:

XMLFilterImpl.startElement(String, String, String, Attributes)

endElement

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

Overrides the default endElement method. This method performs internal operations.

Specified by:

endElement in interface org.xml.sax.ContentHandler

Overrides:

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

Parameters:

uri - - the element's namespace URI

localName - - the element's localname

qName - - the element's qualified name

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing.

See Also:

XMLFilterImpl.endElement(String, String, String)

characters

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

Overrides the default characters method. This version of the method removes whitespace from PCDATA within the XML file unless the xml:space attribute is set to preserve.

Specified by:

characters in interface org.xml.sax.ContentHandler

Overrides:

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

Parameters:

ch - - an array of characters

start - - the starting position in the array

length - - the number of characters to use from the array

Throws:

org.xml.sax.SAXException - the superclass may throw an exception during processing.

See Also:

XMLFilterImpl.characters(char[], int, int)

ignorableWhitespace

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

Overrides the default ignorableWhitespace method. When a DTD is present in the XML file, inter-element whitespace causes an ignorableWhitespace SAXEvent to occur rather then the normal characters SAXEvent. This method ensures that such space is removed should a DTD be present.

Specified by:

ignorableWhitespace in interface org.xml.sax.ContentHandler

Overrides:

ignorableWhitespace in class org.xml.sax.helpers.XMLFilterImpl

Parameters:

ch - - an array of characters

start - - the starting position in the array

length - - the number of characters to use from the array

Throws:

org.xml.sax.SAXException - the superclass may thrown an exception during processing.

See Also:

XMLFilterImpl.ignorableWhitespace(char[], int, int)