The interfaces represents the namespace schema information information
item. Each namespace schema information information item corresponds to
an XML Schema with unique namespace name.
The interface may be updated or replaced.
[schema components]: a list of top-level components, i.e. element
declarations, attribute declarations, etc.
param
objectType The type of the declaration, i.e.
ELEMENT_DECLARATION. Note that
XSTypeDefinition.SIMPLE_TYPE and
XSTypeDefinition.COMPLEX_TYPE can also be used as the
objectType to retrieve only complex types or simple
types, instead of all types.
return
A list of top-level definition of the specified type in
objectType or null.