=head1 NAME

XmlValue - A Perl interface to the DbXml XmlValue Class

=head1 SYNOPSIS

    use Sleepycat::DbXml;

    my $v = new XmlValue()
    my $v = new XmlValue(VALUE);
    my $v = new XmlValue(TYPE, VALUE);
    my $v = new XmlValue(typeURI, typeName, stringValue);

    my $type = $v->getType();
    my $type = $v->getTypeName();
    my $uri  = $v->getTypeURI();

    my $boolean  = $v->isNull;
    my $boolean  = $v->isType(TYPE);
    my $boolean  = $v->isBoolean();
    my $boolean  = $v->isNumber();
    my $boolean  = $v->isString();
    my $boolean  = $v->isNode();
    my $boolean  = $v->isBinary();

    my $boolean  = $v->asBoolean();
    my $number   = $v->asNumber();
    my $string   = $v->asString();
    my $document = $v->asDocument();
    my $document = $v->asBinary();

    my $reader   = $v->asEventReader();
    $v->equals($v2);

    # Node traversal
    my $string   = $v->getNodeName() ;
    my $string   = $v->getNodeValue() ;
    my $string   = $v->getNamespaceURI() ;
    my $string   = $v->getPrefix() ;
    my $string   = $v->getLocalName() ;
    my $type     = $v->getNodeType() ;
    my $xmlvalue = $v->getParentNode() ;
    my $xmlvalue = $v->getFirstChild() ;
    my $xmlvalue = $v->getLastChild() ;
    my $xmlvalue = $v->getPreviousSibling() ;
    my $xmlvalue = $v->getNextSibling() ;
    my $xmlvalue = $v->getAttributes() ;
    my $xmlvalue = $v->getOwnerElement();


=head1 DESCRIPTION



=head1 CONFORMANCE to C++ API

The Perl interface to XMlValue is identical to the C++ API, apart from
the following

=over 5

=item 1.

No Perl interface is provided to the asNode method.

=item 2

Addition of getTypeName method.


=item 3.

The Node traversal methods are implemented but untested at present.

=back


=head1 Constructor

The constructor for XmlValue can take one of the following four forms:

    my $value = new XmlValue() ;
    my $value = new XmlValue(VALUE);
    my $value = new XmlValue(TYPE, VALUE);
    my $v = new XmlValue(typeURI, typeName, stringValue);

The first form, with no parameters, will create an empty XmlValue.

The second, with one parameter, creates and initialises an XmlValue
of type XmlValue::STRING. Value can be an XMlDocument object, another
XmlValue object or a simple Perl scalar.

The third form creates and initialises an XmlValue of the specified type.

The TYPE parameter can be one of the following

    XmlValue::NONE 
    XmlValue::NODE 
    XmlValue::ANY_SIMPLE_TYPE 
    XmlValue::ANY_URI 
    XmlValue::BASE_64_BINARY 
    XmlValue::BOOLEAN 
    XmlValue::DATE 
    XmlValue::DATE_TIME 
    XmlValue::DAY_TIME_DURATION 
    XmlValue::DECIMAL 
    XmlValue::DOUBLE 
    XmlValue::DURATION 
    XmlValue::FLOAT 
    XmlValue::G_DAY 
    XmlValue::G_MONTH 
    XmlValue::G_MONTH_DAY 
    XmlValue::G_YEAR 
    XmlValue::G_YEAR_MONTH 
    XmlValue::HEX_BINARY 
    XmlValue::NOTATION 
    XmlValue::QNAME 
    XmlValue::STRING 
    XmlValue::TIME 
    XmlValue::YEAR_MONTH_DURATION 
    XmlValue::UNTYPED_ATOMIC 
    XmlValue::BINARY 


The VALUE parameter is the value you want stored in the XmlValue object.

XmlValue objects are overloaded to allow convenient access to their
contents. Stringification of an XmlValue object or comparison of one
(or more) XmValue objects will automagically result in the asString
method being called.

=head1 Methods

=head2 my $type = $v->getType()

Returns the numeric representation of the type of the XmlValue. The
value returned will match one of the the TYPE constants defined in the
constructor section, above.

=head2 my $type = $v->getTypeName()

Returns a string representation of the type of the XmlValue. The
string returned will match one of the the TYPE constants defined in the
constructor section, above.

=head2 my $uri = $v->getType()

return the URI for the type.

=head2 my $boolean = $v->isNull

Returns true if $v is null, otherwize returns false.

=head2 my $boolean  = $v->isBoolean()

Returns true if $v has type XmlValue::BOOLEAN, otherwise returns false.

The $context parameter is optional, but if present must be a valid
XmlQueryContext object.

=head2 my $boolean  = $v->isNumber();

Returns true if $v has type XmlValue::NUMBER, otherwise returns false.


=head2 my $boolean  = $v->isString();

Returns true if $v has type XmlValue::STRING, otherwise returns false.

=head2 my $boolean  = $v->isNode();

Returns true if $v has type XmlValue::NODE, otherwise returns false.

=head2 my $boolean  = $v->asBoolean();

Returns the value of the XmlValue as a Boolean. 

=head2 my $number   = $v->asNumber();

Returns the value of the XmlValue as a Number.

=head2 my $string   = $v->asString();

Returns the value of the XmlValue as a String.

=head2 my $document = $v->asDocument();

Returns the value of the XmlValue as a Document.

=head2 $v->equals($v2);

Returns true if $v and $v2 represrnt the same value.

=head2    my $string   = $v->getNodeName() ;

=head2    my $string   = $v->getNodeValue() ;

=head2    my $string   = $v->getNamespaceURI() ;

=head2    my $string   = $v->getPrefix() ;

=head2    my $string   = $v->getLocalName() ;

=head2    my $type     = $v->getNodeType() ;

=head2    my $xmlvalue = $v->getParentNode() ;

=head2    my $xmlvalue = $v->getFirstChild() ;

=head2    my $xmlvalue = $v->getLastChild() ;

=head2    my $xmlvalue = $v->getPreviousSibling() ;

=head2    my $xmlvalue = $v->getNextSibling() ;

=head2    my $xmlvalue = $v->getAttributes() ;

=head2    my $xmlvalue = $v->getOwnerElement();

=head1 EXAMPLES

    use strict;
    use warnings;

    use DbXml;

    my $mgr = new XMlManager();

    # Create an empty object
    my $value1 = new XmlValue ;

    # Create and initialise a string
    my $value2 = new XmlValue("alpha");

    # Create and initialise another string
    my $value3 = new XmlValue(XmlValue::STRING, "beta");

    # Create and initialise a number
    my $value4 = new XmlValue(XmlValue::DECIMAL, 42);

    print "value2 contains " . $value2->asString() . "\n" ;

    # Same as above using overloaded stringification XmlValue
    print "value2 contains $value2"\n" ;

    print "value4 is a DECIMAL\n"
        if $value4->getType == XmlValue::DECIMAL ;
    

=head1 NOTES



=head1 SEE ALSO


=head1 AUTHOR

Paul Marquess