# +===========================================================================+
# |                                                                           |
# |                    NATIONAL GEOSPATIAL DIGITAL ARCHIVE                    |
# |                 University of California at Santa Barbara                 |
# |                                                                           |
# +===========================================================================+

# $Header: /export/home/gjanee/ngda/data-model/RCS/template.rnc,v 1.2 2006/02/15 18:08:40 gjanee Exp $

# DESCRIPTION
#
#     RELAX NG schema for archival object templates.
#
#     A template defines the common structure of a class of objects.
#     It is essentially identical to a manifest, except that
#     quantities that are specific to individual objects (object
#     identifiers, file sizes, etc.) are not present, and in a
#     template components may be marked as optional.
#
#     A template is purely an ingest aid.  An archival object may, at
#     any time, deviate from the structure specified by an associated
#     template.
#
#     Storage note: the storage of templates has been left
#     deliberately ambiguous in this specification.  Templates may be
#     stored as archival objects in the archive, or, they may be
#     stored by the archive server by any other means.  The only
#     requirement either way is that they be referencable by URI.
#
#     If a template is stored as an archival object, the recommended
#     representation is to store it as a file named "template.xml" in
#     the archival object's root directory.  In other words, templates
#     adhere to the following meta-template:
#
#         <template>
#           <templateIdentifier>meta-template</templateIdentifier>
#           <file>
#             <name>template.xml</name>
#             <definitionRef> (this specification) </definitionRef>
#           </file>
#         </template>
#
# AUTHOR
#
#     Greg Janee
#     gjanee@alexandria.ucsb.edu
#
# HISTORY
#
#     $Log: template.rnc,v $
#     Revision 1.2  2006/02/15 18:08:40  gjanee
#     Parallel changes to match those made to manifest.rnc.  Also,
#     added an "optional" attribute to components.  This schema is
#     fully backward-compatible with the previous version except for
#     the version change in the XML namespace.  (There is a new
#     restriction on object identifiers that is not
#     backward-compatible in theory, but in practice the change should
#     have no implications.)
#
#     Revision 1.1  2005/11/14 00:38:13  gjanee
#     Initial revision
#

default namespace = "tag:ngda.org,2005:schemas/1.1/template"

namespace a = "http://relaxng.org/ns/compatibility/annotations/1.0"

grammar {

  # Note that the identifier here identifies the template.

  start = element template {
    element templateIdentifier { xsd:anyURI },
    Relationship*,
    Definition*,
    Lineage?,
    Component*
  }

  Relationship = element relationship {
    attribute type { text },
    attribute targetObjectRef { xsd:anyURI }
  }

  Component = Directory | File

  CommonComponentElements =
    [a:defaultValue="false"] attribute optional { xsd:boolean }?,
    element name { xsd:NCName },
    Definition*,
    Lineage?

  Directory = element directory {
    attribute type { "subcomponents" | "alternatives" },
    CommonComponentElements,
    Component*
  }

  File = element file {
    CommonComponentElements
  }

  Definition = element definitionRef { xsd:anyURI }

  Lineage = element lineage {
    element sourceComponentRef { xsd:anyURI }*,
    element notes { text }?
  }

  # The extra-schema validity checks listed in manifest.rnc apply to
  # templates as well.

}