function MetaTagHandler(next) {
	
	DMCommandHandler.apply(this, [next]);
	this.process = function(command) {
		
		with(command.triple) {
			
			/* assert prerequisites */
			if( !(
				(subject instanceof ERDF.Resource) &&
				(subject.isCurrentDocument()) &&
				(object instanceof ERDF.Literal)
			))	return false;
		}
		
	};
}
This Handler manages the addition and the removal of meta elements in the
head of the document.
@param {DMCommandHandler} next The handler that is next in the chain.