Name the attributes the Mission Data Product area was aliasing

The area declared ProductToken, ProductPath and SubscriptionId as
composites that extend String, URI and Identifier, each with no fields
of its own. They were not structures but attempts at naming an
attribute, and the MAL data model has no way to say that: Composite and
Attribute are separate branches of the type hierarchy, and the set of
attributes is closed by the MAL area.

The schema could not object, because it types the extends element as a
plain reference and only its documentation says the target is meant to
be a Composite. The document generator could, and did: it looks a super
type up among the composites, finds nothing, and abandons the whole
area. ProductToken is the first type declared, so the area has been
producing no document at all, while the run that produced nothing
reported success.

The three are removed and the eighteen fields that used them now name
String, URI and Identifier directly, which is what they carried anyway.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: CesarCoelho

xml-service-specifications/xml-ccsds-mo-prototypes/src/main/resources/xml/area051-v001-Mission-Data-Product.xml

@@ -11,7 +11,7 @@
 							<mal:field name="root" canBeNull="false"
 									comment="Identifies the root for the search.
 									E.g. /mission-x/attitude/ identifies the collection of attitude files for mission-x, and / indentifies the whole archive">
-									<mal:type name="ProductPath" area="MDP"/>
+									<mal:type name="URI" area="MAL"/>
 							</mal:field>
 							<mal:field name="filter" canBeNull="true"
 										comment="Optional filter to be applied on the product metadata">
@@ -35,7 +35,7 @@
 						<mal:response
 	                  	comment="Returns the list of items that match the search">
 							<mal:field name="token" comment="Decided to return single token during Fall meeting 2019">
-								<mal:type list="true" name="ProductToken" area="MDP" />
+								<mal:type list="true" name="String" area="MAL" />
 							</mal:field>
 						</mal:response>
 					</mal:messages>
@@ -70,7 +70,7 @@
 						<mal:response
 											comment="Returns the list of items that match the search">
 							<mal:field name="subscriptionId" comment="Decided to return single token during Fall meeting 2019">
-								<mal:type list="false" name="SubscriptionId" area="MDP" />
+								<mal:type list="false" name="Identifier" area="MAL" />
 							</mal:field>
 						</mal:response>
 					</mal:messages>
@@ -96,7 +96,7 @@
 						<mal:submit>
 							<mal:field name="ids" canBeNull="true"
 				            comment="Identifies the product type">
-								<mal:type list="true" name="SubscriptionId" area="MDP"/>
+								<mal:type list="true" name="Identifier" area="MAL"/>
 							</mal:field>
 						</mal:submit>
 					</mal:messages>
@@ -132,7 +132,7 @@
 						<mal:invoke comment="">
 							<mal:field name="token" canBeNull="false"
 				            comment="Identifier that univocally identifies one product item for a given provider">
-								<mal:type name="ProductToken" area="MDP"  list="true"/>
+								<mal:type name="String" area="MAL"  list="true"/>
 							</mal:field>
 							<mal:field name="preFetch" canBeNull="true"
 				            comment="If true, only the attributes are returned not any data.">
@@ -171,7 +171,7 @@
 							<mal:field name="path" canBeNull="false"
 				            comment="Identifies the root for the search.
 				            E.g. /mission-x/attitude/ identifies the collection of attitude files for mission-x, and / indentifies the whole archive">
-								<mal:type name="ProductPath" area="MDP"/>
+								<mal:type name="URI" area="MAL"/>
 							</mal:field>
 							<mal:field name="limitPaths" canBeNull="true"
 				            comment="Limit the number of records returned by the get operation.
@@ -189,10 +189,10 @@
 						<mal:response
 	                  	comment="Returns the list of product types that match the search">
 							<mal:field name="paths" canBeNull="false" comment="List of sub-folders for the current path">
-								<mal:type list="true" name="ProductPath" area="MDP"/>
+								<mal:type list="true" name="URI" area="MAL"/>
 							</mal:field>
 							<mal:field name="tokens" canBeNull="false" comment="Tokens to request products on the current path">
-							<mal:type list="true" name="ProductToken" area="MDP"/>
+							<mal:type list="true" name="String" area="MAL"/>
 							</mal:field>
 						</mal:response>
 					</mal:messages>
@@ -215,7 +215,7 @@
 						<mal:response
 											comment="Returns token for the created product">
 							<mal:field name="token" comment="Asafvvz">
-								<mal:type list="false" name="ProductToken" area="MDP" />
+								<mal:type list="false" name="String" area="MAL" />
 							</mal:field>
 						</mal:response>
 					</mal:messages>
@@ -236,7 +236,7 @@
 					<mal:messages>
 						<mal:submit>
 							<mal:field name="token" comment="Token of the product to be updated">
-								<mal:type list="false" name="ProductToken" area="MDP" />
+								<mal:type list="false" name="String" area="MAL" />
 							</mal:field>
 							<mal:field name="productData" canBeNull="false"
 				            comment="New data for the product">
@@ -262,7 +262,7 @@
 						<mal:submit>
 							<mal:field name="tokens" canBeNull="false"
 				            comment="Tokens for the products beeing deleted">
-								<mal:type name="ProductToken" list="true" area="MDP"/>
+								<mal:type name="String" list="true" area="MAL"/>
 							</mal:field>
 						</mal:submit>
 					</mal:messages>
@@ -333,7 +333,7 @@
 						<mal:submit>
 							<mal:field name="productPath" canBeNull="false"
 				            comment="Path and details for the product being added">
-								<mal:type name="ProductPath" area="MDP"/>
+								<mal:type name="URI" area="MAL"/>
 							</mal:field>
 						</mal:submit>
 					</mal:messages>
@@ -353,35 +353,13 @@
 			</mal:capabilitySet>
 		</mal:service>
 		<mal:dataTypes>
-			<mal:composite name="ProductToken" shortFormPart="10"
-         	comment="This token will allow a product to be fetched. A token might be a path to a specific product (e.g. /mission-x/orbit/orbit_file_12345) or any other sort of unique identifier (e.g. implementation specific checksum of the file). Some tokens might be deducible (e.g. /mission-y/sensor-x/YYYY-MM-DD) and thus don't need to be searched. The creation strategy for tokens is implementation specific">
-				<mal:extends>
-					<mal:type name="String" area="MAL"/>
-				</mal:extends>
-			</mal:composite>
-			<mal:composite name="ProductPath" shortFormPart="20"
-         	comment="Path that univocally identifies one or more items (products or product types) offered by a provider. The path is local to the provider.
-         	As long as it is unique for a given provider, this field can take any valid path value as defined in RFC3986:relative-part,
-         	e.g. /mission-x/orbit/orbit_file_12345.xml to identify a specific file, or /mission-x/attitude/ to identify the collection of attitude files for mission-x ">
-				<mal:extends>
-					<mal:type name="URI" area="MAL"/>
-				</mal:extends>
-			</mal:composite>
-
-			<mal:composite name="SubscriptionId" shortFormPart="25"
-         	comment="cmt">
-				<mal:extends>
-					<mal:type name="Identifier" area="MAL"/>
-				</mal:extends>
-			</mal:composite>
-
 			<mal:composite name="ProductType" shortFormPart="30"
 			comment="Identifies a product or product type, with an optional metadata">
 				<mal:extends>
 					<mal:type name="Composite" area="MAL"/>
 				</mal:extends>
 				<mal:field name="path" canBeNull="false" comment="">
-					<mal:type name="ProductPath" area="MDP"/>
+					<mal:type name="URI" area="MAL"/>
 				</mal:field>
 				<mal:field name="metadata" canBeNull="true" comment="Metadata common to all products in this path">
 					<mal:type list="true" name="NamedValue" area="MAL"/>
@@ -393,7 +371,7 @@
 					<mal:type name="Composite" area="MAL"/>
 				</mal:extends>
 				<mal:field name="path" canBeNull="false" comment="e.g. /mission-x/orbit/orbit_file_12345">
-					<mal:type name="ProductPath" area="MDP"/>
+					<mal:type name="URI" area="MAL"/>
 				</mal:field>
 				<mal:field name="attributes" canBeNull="true" comment="Searchable attributes specific to this product">
 					<mal:type list="true" name="ProductAttributes" area="MDP"/>
@@ -441,7 +419,7 @@
 				<mal:field name="root" canBeNull="false"
 						comment="Identifies the root for the search.
 						E.g. /mission-x/attitude/ identifies the collection of attitude files for mission-x, and / indentifies the whole archive">
-						<mal:type name="ProductPath" area="MDP"/>
+						<mal:type name="URI" area="MAL"/>
 				</mal:field>
 				<mal:field name="filter" canBeNull="true"
 							comment="Optional filter to be applied on the product metadata">
@@ -483,7 +461,7 @@
 				</mal:extends>
 
 				<mal:field name="subscriptionId" canBeNull="false" comment="Decided to return single token during Fall meeting 2019">
-					<mal:type list="false" name="SubscriptionId" area="MDP" />
+					<mal:type list="false" name="Identifier" area="MAL" />
 				</mal:field>
 
 				<mal:field name="type" canBeNull="false"