This interface represents the ElementDeclaration component described in the WSDL 2.0 Component Model specification (within the Description Component section). An ElementDeclaration refers to an element, such as a global element declaration in the XML Schema type system (<xs:element>), that describes the content of WSDL input, output and fault messages. However, it does not impose XML Schema as the type system. It returns a String representing the content model or type system (e.g. "http://www.w3.org/2001/XMLSchema") and a java.lang.Object representing the content of the element declaration. This Object may be cast to a type appropriate for the content model. TODO consider whether this interface should extend WSDLComponent too (i.e. it is described in the spec within the Description component section, but it doesn't correspond directly to a WSDL element).