protected function generateNullValue(\XmlWriter $writer, $key = null, $elementName = 'value')
    {
        $writer->startElement($elementName);
        $this->generateKeyAttribute($writer, $key);
        // @todo: xsi:type?
        $writer->endElement();
    }
protected function generateNullValue(\XmlWriter $writer, $key = null, $elementName = 'value')
    {
        $writer->startElement($elementName);
        $this->generateKeyAttribute($writer, $key);
        // @todo: xsi:type?
        $writer->endElement();
    }
protected function generateNullValue ( \ XmlWriter $ writer , $ key = null , $ elementName = 'value' ) { $ writer -> startElement ( $ elementName ) ; $ this -> generateKeyAttribute ( $ writer , $ key ) ; // @todo: xsi:type? $ writer -> endElement ( ) ; }
Generates a null value.

@param \XmlWriter $writer
@param string|null $key
@param string $elementName
Generates a null value .