nu.xom.canonical

Class 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.

Version: 1.2d1

Author: Elliotte Rusty Harold

Field Summary
static StringCANONICAL_XML
static StringCANONICAL_XML_WITH_COMMENTS
static StringEXCLUSIVE_XML_CANONICALIZATION
static StringEXCLUSIVE_XML_CANONICALIZATION_WITH_COMMENTS
Constructor Summary
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
voidsetInclusiveNamespacePrefixList(String inclusiveNamespacePrefixes)

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

voidwrite(Node node)

Serializes a node onto the output stream using the specified canonicalization algorithm.

voidwrite(Nodes documentSubset)

Serializes a document subset onto the output stream using the canonical XML algorithm.

Field Detail

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 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:

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

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

write

public final void write(Node node)

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)

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

Copyright 2002-2006 Elliotte Rusty Harold
elharo@metalab.unc.edu