Class Canonicalizer

java.lang.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 Details

  • 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, 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 Details

    • 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