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NamespaceSupport(3pm) User Contributed Perl DocumentationNamespaceSupport(3pm)



NAME
       XML::NamespaceSupport - a simple generic namespace support class

SYNOPSIS
         use XML::NamespaceSupport;
         my $nsup = XML::NamespaceSupport->new;

         # add a new empty context
         $nsup->push_context;
         # declare a few prefixes
         $nsup->declare_prefix($prefix1, $uri1);
         $nsup->declare_prefix($prefix2, $uri2);
         # the same shorter
         $nsup->declare_prefixes($prefix1 => $uri1, $prefix2 => $uri2);

         # get a single prefix for a URI (randomly)
         $prefix = $nsup->get_prefix($uri);
         # get all prefixes for a URI (probably better)
         @prefixes = $nsup->get_prefixes($uri);
         # get all prefixes in scope
         @prefixes = $nsup->get_prefixes();
         # get all prefixes that were declared for the current scope
         @prefixes = $nsup->get_declared_prefixes;
         # get a URI for a given prefix
         $uri = $nsup->get_uri($prefix);

         # get info on a qname (java-ish way, it's a bit weird)
         ($ns_uri, $local_name, $qname) = $nsup->process_name($qname, $is_attr);
         # the same, more perlish
         ($ns_uri, $prefix, $local_name) = $nsup->process_element_name($qname);
         ($ns_uri, $prefix, $local_name) = $nsup->process_attribute_name($qname);

         # remove the current context
         $nsup->pop_context;

         # reset the object for reuse in another document
         $nsup->reset;

         # a simple helper to process Clarkian Notation
         my ($ns, $lname) = $nsup->parse_jclark_notation('{http://foo}bar');
         # or (given that it doesn't care about the object
         my ($ns, $lname) = XML::NamespaceSupport->parse_jclark_notation('{http://foo}bar');

DESCRIPTION
       This module offers a simple to process namespaced XML names (unames)
       from within any application that may need them. It also helps maintain
       a prefix to namespace URI map, and provides a number of basic checks.

       The model for this module is SAX2's NamespaceSupport class, readable at
       http://www.megginson.com/SAX/Java/javadoc/org/xml/sax/helpers/Names-
       paceSupport.html.  It adds a few perlisations where we thought it
       appropriate.

METHODS
       * XML::NamespaceSupport->new(\%options)
           A simple constructor.

           The options are "xmlns", "fatal_errors", and "auto_prefix"

           If "xmlns" is turned on (it is off by default) the mapping from the
           xmlns prefix to the URI defined for it in DOM level 2 is added to
           the list of predefined mappings (which normally only contains the
           xml prefix mapping).

           If "fatal_errors" is turned off (it is on by default) a number of
           validity errors will simply be flagged as failures, instead of
           die()ing.

           If "auto_prefix" is turned on (it is off by default) when one pro-
           vides a prefix of "undef" to "declare_prefix" it will generate a
           random prefix mapped to that namespace. Otherwise an undef prefix
           will trigger a warning (you should probably know what you're doing
           if you turn this option on).

           If "xmlns_11" us turned off, it becomes illegal to undeclare names-
           pace prefixes. It is on by default. This behaviour is compliant
           with Namespaces in XML 1.1, turning it off reverts you to version
           1.0.

       * $nsup->push_context
           Adds a new empty context to the stack. You can then populate it
           with new prefixes defined at this level.

       * $nsup->pop_context
           Removes the topmost context in the stack and reverts to the previ-
           ous one. It will die() if you try to pop more than you have pushed.

       * $nsup->declare_prefix($prefix, $uri)
           Declares a mapping of $prefix to $uri, at the current level.

           Note that with "auto_prefix" turned on, if you declare a prefix
           mapping in which $prefix is undef(), you will get an automatic pre-
           fix selected for you. If it is off you will get a warning.

           This is useful when you deal with code that hasn't kept prefixes
           around and need to reserialize the nodes. It also means that if you
           want to set the default namespace (ie with an empty prefix) you
           must use the empty string instead of undef. This behaviour is con-
           sistent with the SAX 2.0 specification.

       * $nsup->declare_prefixes(%prefixes2uris)
           Declares a mapping of several prefixes to URIs, at the current
           level.

       * $nsup->get_prefix($uri)
           Returns a prefix given an URI. Note that as several prefixes may be
           mapped to the same URI, it returns an arbitrary one. It'll return
           undef on failure.

       * $nsup->get_prefixes($uri)
           Returns an array of prefixes given an URI. It'll return all the
           prefixes if the uri is undef.

       * $nsup->get_declared_prefixes
           Returns an array of all the prefixes that have been declared within
           this context, ie those that were declared on the last element, not
           those that were declared above and are simply in scope.

       * $nsup->get_uri($prefix)
           Returns a URI for a given prefix. Returns undef on failure.

       * $nsup->process_name($qname, $is_attr)
           Given a qualified name and a boolean indicating whether this is an
           attribute or another type of name (those are differently affected
           by default namespaces), it returns a namespace URI, local name,
           qualified name tuple. I know that that is a rather abnormal list to
           return, but it is so for compatibility with the Java spec. See
           below for more Perlish alternatives.

           If the prefix is not declared, or if the name is not valid, it'll
           either die or return undef depending on the current setting of
           "fatal_errors".

       * $nsup->undeclare_prefix($prefix);
           Removes a namespace prefix from the current context. This function
           may be used in SAX's end_prefix_mapping when there is fear that a
           namespace declaration might be available outside their scope (which
           shouldn't normally happen, but you never know ;). This may be
           needed in order to properly support Namespace 1.1.

       * $nsup->process_element_name($qname)
           Given a qualified name, it returns a namespace URI, prefix, and
           local name tuple. This method applies to element names.

           If the prefix is not declared, or if the name is not valid, it'll
           either die or return undef depending on the current setting of
           "fatal_errors".

       * $nsup->process_attribute_name($qname)
           Given a qualified name, it returns a namespace URI, prefix, and
           local name tuple. This method applies to attribute names.

           If the prefix is not declared, or if the name is not valid, it'll
           either die or return undef depending on the current setting of
           "fatal_errors".

       * $nsup->reset
           Resets the object so that it can be reused on another document.

       All methods of the interface have an alias that is the name used in the
       original Java specification. You can use either name interchangeably.
       Here is the mapping:

         Java name                 Perl name
         ---------------------------------------------------
         pushContext               push_context
         popContext                pop_context
         declarePrefix             declare_prefix
         declarePrefixes           declare_prefixes
         getPrefix                 get_prefix
         getPrefixes               get_prefixes
         getDeclaredPrefixes       get_declared_prefixes
         getURI                    get_uri
         processName               process_name
         processElementName        process_element_name
         processAttributeName      process_attribute_name
         parseJClarkNotation       parse_jclark_notation
         undeclarePrefix           undeclare_prefix

VARIABLES
       Two global variables are made available to you. They used to be con-
       stants but simple scalars are easier to use in a number of contexts.
       They are not exported but can easily be accessed from any package, or
       copied into it.

       * $NS_XMLNS
           The namespace for xmlns prefixes, http://www.w3.org/2000/xmlns/.

       * $NS_XML
           The namespace for xml prefixes, http://www.w3.org/XML/1998/names-
           pace.

TODO
        - add more tests
        - optimise here and there

AUTHOR
       Robin Berjon, robinATknowscape.com, with lots of it having been done by
       Duncan Cameron, and a number of suggestions from the perl-xml list.

COPYRIGHT
       Copyright (c) 2001-2005 Robin Berjon. All rights reserved. This program
       is free software; you can redistribute it and/or modify it under the
       same terms as Perl itself.

SEE ALSO
       XML::Parser::PerlSAX



perl v5.8.8                       2006-11-17             NamespaceSupport(3pm)