nu.xom.canonical

Class Canonicalizer


public class Canonicalizer
extends java.lang.Object

Writes XML in the format specified by Canonical XML Version 1.0 or Exclusive XML Canonicalization Version 1.0.
Version:
1.2b3
Author:
Elliotte Rusty Harold

Field Summary

static String
CANONICAL_XML
static String
CANONICAL_XML_WITH_COMMENTS
static String
EXCLUSIVE_XML_CANONICALIZATION
static String
EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

Constructor Summary

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

Method Summary

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.

Field Details

CANONICAL_XML

public static final String CANONICAL_XML

CANONICAL_XML_WITH_COMMENTS

public static final String CANONICAL_XML_WITH_COMMENTS

EXCLUSIVE_XML_CANONICALIZATION

public static final String EXCLUSIVE_XML_CANONICALIZATION

EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

public static final String EXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS

Constructor Details

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,
                     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

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

Method Details

setInclusiveNamespacePrefixList

public final void setInclusiveNamespacePrefixList(String inclusiveNamespacePrefixes)
            throws IOException
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

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

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

Copyright 2002-2009 Elliotte Rusty Harold
elharo@metalab.unc.edu