nu.xom.canonical

Class Canonicalizer

Object

nu.xom.canonical.Canonicalizer

public class Canonicalizer
extends Object

Writes XML in the format specified by Canonical XML Version 1.0 or Exclusive XML Canonicalization Version 1.0. Canonical XML 1.1 support is in progress.

Version:

1.3.1

Author:

Elliotte Rusty Harold

Field Summary

Fields

Modifier and Type	Field and Description
static String	CANONICAL_XML
static String	CANONICAL_XML_11
static String	CANONICAL_XML_11_WITH_COMMENTS
static String	CANONICAL_XML_WITH_COMMENTS
static String	EXCLUSIVE_XML_CANONICALIZATION
static String	EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

Constructor Summary

Constructors

Constructor and Description
Canonicalizer(OutputStream out) Creates a Canonicalizer that outputs a canonical XML document with comments.
Canonicalizer(OutputStream out, boolean withComments) Creates a Canonicalizer that outputs a canonical XML document with or without comments.
Canonicalizer(OutputStream out, String algorithm) Creates a Canonicalizer that outputs a canonical XML document using the specified algorithm.

Method Summary

Modifier and Type	Method and Description
void	setInclusiveNamespacePrefixList(String inclusiveNamespacePrefixes) Specifies the prefixes that will be output as specified in regular canonical XML, even when doing exclusive XML canonicalization.
void	write(Node node) Serializes a node onto the output stream using the specified canonicalization algorithm.
void	write(Nodes documentSubset) Serializes a document subset onto the output stream using the canonical XML algorithm.

Methods inherited from class Object

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

Field Detail

CANONICAL_XML

public static final String CANONICAL_XML

See Also:

Constant Field Values

CANONICAL_XML_WITH_COMMENTS

public static final String CANONICAL_XML_WITH_COMMENTS

See Also:

Constant Field Values

EXCLUSIVE_XML_CANONICALIZATION

public static final String EXCLUSIVE_XML_CANONICALIZATION

See Also:

Constant Field Values

EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

public static final String EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

See Also:

Constant Field Values

CANONICAL_XML_11

public static final String CANONICAL_XML_11

See Also:

Constant Field Values

CANONICAL_XML_11_WITH_COMMENTS

public static final String CANONICAL_XML_11_WITH_COMMENTS

See Also:

Constant Field Values

Constructor Detail

Canonicalizer

public Canonicalizer(OutputStream out)

Creates a Canonicalizer that outputs a canonical XML document with comments.

Parameters:

out - the output stream the document is written onto

Canonicalizer

public Canonicalizer(OutputStream out,
                     boolean withComments)

Creates a Canonicalizer that outputs a canonical XML document with or without comments.

Parameters:

out - the output stream the document is written onto

withComments - true if comments should be included in the output, false otherwise

Canonicalizer

public Canonicalizer(OutputStream out,
                     String algorithm)

Creates a Canonicalizer that outputs a canonical XML document using the specified algorithm. Currently, four algorithms are defined and supported:

• Canonical XML without comments: http://www.w3.org/TR/2001/REC-xml-c14n-20010315
• Canonical XML with comments: http://www.w3.org/TR/2001/REC-xml-c14n-20010315#WithComments
• Exclusive XML canonicalization without comments: http://www.w3.org/2001/10/xml-exc-c14n#
• Exclusive XML canonicalization with comments: http://www.w3.org/2001/10/xml-exc-c14n#WithComments

Parameters:

out - the output stream the document is written onto

algorithm - the URI for the canonicalization algorithm

Throws:

CanonicalizationException - if the algorithm is not recognized

NullPointerException - if the algorithm is null

Method Detail

write

public final void write(Node node)
                 throws IOException

Serializes a node onto the output stream using the specified canonicalization algorithm. If the node is a document or an element, then the node's entire subtree is written out.

Parameters:

node - the node to canonicalize

Throws:

IOException - if the underlying OutputStream encounters an I/O error

write

public final void write(Nodes documentSubset)
                 throws IOException

Serializes a document subset onto the output stream using the canonical XML algorithm. All nodes in the list must come from same document. Furthermore, they must come from a document. They cannot be detached. The nodes need not be sorted. This method will sort them into the appropriate order for canonicalization.

In most common use cases, these nodes will be the result of evaluating an XPath expression. For example,

 Canonicalizer canonicalizer 
   = new Canonicalizer(System.out, Canonicalizer.CANONICAL_XML);
 Nodes result = doc.query("//. | //@* | //namespace::*");
 canonicalizer.write(result);  
 

Children are not output unless the subset also includes them. Including an element in the subset does not automatically select all the element's children, attributes, and namespaces. Furthermore, not selecting an element does not imply that its children, namespaces, attributes will not be output.

Parameters:

documentSubset - the nodes to serialize

Throws:

IOException - if the underlying OutputStream encounters an I/O error

CanonicalizationException - if the nodes come from more than one document; or if a detached node is in the list

setInclusiveNamespacePrefixList

public final void setInclusiveNamespacePrefixList(String inclusiveNamespacePrefixes)

Specifies the prefixes that will be output as specified in regular canonical XML, even when doing exclusive XML canonicalization.

Parameters:

inclusiveNamespacePrefixes - a whitespace separated list of namespace prefixes that will always be included in the output, even in exclusive canonicalization