From 74d93e43a7b86832ca525365ebf2929dfbf8022b Mon Sep 17 00:00:00 2001
From: galtm <40716346+galtm@users.noreply.github.com>
Date: Fri, 15 Apr 2022 14:58:07 -0500
Subject: [PATCH] Profile resolver: Metadata tests and way of determining top
 UUID (#1175)

- Metadata tests and way of determining top UUID
- Remove global parameter assign-uuid (note backward incompatibility - is it OK?)
- Instead, support global parameters uuid-method and top-uuid, in uuid-method-choice.xsl
- Support global parameter hide-source-profile-uri
- Stub of opr:oscal-version function
- Stub of message handler template, using xsl:message for now
- Add XSpec tests
- Add table of parameters and clarify testing folder content
- Change "home" from global param to global variable; does not need to be set from outside
---
 .../example-set.xspec                         |   3 +-
 .../resolver-pipeline/message-handler.xsl     |  19 +
 .../oscal-profile-RESOLVE.xsl                 |  51 +-
 .../oscal-profile-resolve-metadata.xsl        |  76 ++-
 src/utils/util/resolver-pipeline/readme.md    |  46 +-
 .../testing/2_metadata/metadata.xspec         | 437 +++++++++++++-----
 .../2_metadata/uuid-method-choice.xspec       |  86 ++++
 .../testing/2_metadata/uuid-value.txt         |   1 +
 .../resolver-pipeline/uuid-method-choice.xsl  |  89 ++++
 9 files changed, 621 insertions(+), 187 deletions(-)
 create mode 100644 src/utils/util/resolver-pipeline/message-handler.xsl
 create mode 100644 src/utils/util/resolver-pipeline/testing/2_metadata/uuid-method-choice.xspec
 create mode 100644 src/utils/util/resolver-pipeline/testing/2_metadata/uuid-value.txt
 create mode 100644 src/utils/util/resolver-pipeline/uuid-method-choice.xsl

diff --git a/src/specifications/profile-resolution/profile-resolution-examples/example-set.xspec b/src/specifications/profile-resolution/profile-resolution-examples/example-set.xspec
index b5d8326d73..e17d79042b 100644
--- a/src/specifications/profile-resolution/profile-resolution-examples/example-set.xspec
+++ b/src/specifications/profile-resolution/profile-resolution-examples/example-set.xspec
@@ -3,7 +3,8 @@
     xmlns:opr="http://csrc.nist.gov/ns/oscal/profile-resolution"
     stylesheet="../../../utils/util/resolver-pipeline/oscal-profile-RESOLVE.xsl"
     run-as="external">
-    <!--<x:param name="assign-uuid">00000000-0000-4000-A000-000000000000</x:param>-->
+    <!--<x:param name="top-uuid">00000000-0000-4000-A000-000000000000</x:param>
+        <x:param name="uuid-method" select="'user-provided'"/>-->
     
 <!-- x:description/@run-as='external' permits the context item to be determined dynamically per scenario
     cf https://github.com/xspec/xspec/wiki/External-Transformation#global-context-item
diff --git a/src/utils/util/resolver-pipeline/message-handler.xsl b/src/utils/util/resolver-pipeline/message-handler.xsl
new file mode 100644
index 0000000000..7b0420fbb7
--- /dev/null
+++ b/src/utils/util/resolver-pipeline/message-handler.xsl
@@ -0,0 +1,19 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet
+    xmlns:mh="http://csrc.nist.gov/ns/message"
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    xmlns:xs="http://www.w3.org/2001/XMLSchema"
+    exclude-result-prefixes="#all"
+    version="3.0">
+    
+    <xsl:template name="mh:message-handler">
+        <xsl:param name="text" as="xs:string"/>
+        <xsl:param name="message-type" as="xs:string?"/><!-- e.g., 'Error', 'Warning' -->
+        <xsl:param name="error-code" as="xs:string?"/>
+        <xsl:param name="terminate" as="xs:boolean" select="false()"/>
+        <xsl:message expand-text="yes" terminate="{$terminate}">{
+            string-join(($message-type, $error-code, $text),': ')
+            }</xsl:message>
+    </xsl:template>
+
+</xsl:stylesheet>
\ No newline at end of file
diff --git a/src/utils/util/resolver-pipeline/oscal-profile-RESOLVE.xsl b/src/utils/util/resolver-pipeline/oscal-profile-RESOLVE.xsl
index 025a5785a9..e4ba2066ba 100644
--- a/src/utils/util/resolver-pipeline/oscal-profile-RESOLVE.xsl
+++ b/src/utils/util/resolver-pipeline/oscal-profile-RESOLVE.xsl
@@ -1,11 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <xsl:stylesheet version="3.0" xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
     xmlns:opr="http://csrc.nist.gov/ns/oscal/profile-resolution"
+    xmlns:u="http://csrc.nist.gov/ns/uuid"
     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xmlns:xs="http://www.w3.org/2001/XMLSchema"
     exclude-result-prefixes="#all"
-    xmlns:javaUUID="java.util.UUID"
-    xmlns:r="http://csrc.nist.gov/ns/random"
     xpath-default-namespace="http://csrc.nist.gov/ns/oscal/1.0">
 
     <!--
@@ -22,8 +21,10 @@
 
     <xsl:output method="xml" indent="yes"/>
 
-    <xsl:import href="random-util.xsl"/>
-    
+    <!-- uuid-method-choice.xsl has global parameters
+        $uuid-method, $top-uuid, and $uuid-service. -->
+    <xsl:import href="uuid-method-choice.xsl"/>
+
     <xsl:strip-space
         elements="catalog group control param guideline select part
         metadata back-matter annotation party person org rlink address resource role responsible-party citation
@@ -35,43 +36,19 @@
 
     <xsl:param name="trace" as="xs:string">off</xsl:param>
     
-    <!-- Provide a top-level UUID for the result catalog as $assign-uuid,
-         or assign-uuid=make-uuid for a native (XSLT 3.0) function call. -->
-    <xsl:param name="assign-uuid" as="xs:string?"/>
-    <!-- Alternatively, call a web site if the processor supports it -->
-    <xsl:param name="uuid-service" select="'https://www.uuidgenerator.net/api/version4'"/>
-    
-    <!-- For checking a UUID before assigning it. -->
-    <xsl:variable name="uuid-v4-regex" as="xs:string">^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-4[0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}$</xsl:variable>
-    
     <xsl:param name="uri-stack" as="xs:anyURI*" select="()"/>
-
-    <xsl:variable name="use-uuid" as="xs:string">
-        <xsl:choose>
-            <xsl:when test="matches($assign-uuid,$uuid-v4-regex)">
-                <xsl:sequence select="$assign-uuid"/>
-            </xsl:when>
-            <xsl:when use-when="function-available('random-number-generator')" test="$assign-uuid = 'make-uuid'">
-                <!-- seed splices a timestamp with a given @uuid -->
-                <xsl:sequence select="r:make-uuid( /*/@uuid || '-' || replace( string(current-dateTime()),'\D','') )"/>
-            </xsl:when>
-            <xsl:when use-when="function-available('javaUUID:randomUUID')" test="function-available('javaUUID:randomUUID')">
-                <xsl:sequence select="javaUUID:randomUUID()"/>
-            </xsl:when>
-            <xsl:when test="unparsed-text-available($uuid-service)">
-                <xsl:sequence select="unparsed-text($uuid-service)"/>
-            </xsl:when>
-            <xsl:otherwise>00000000-0000-4000-B000-000000000000</xsl:otherwise>
-        </xsl:choose>
-    </xsl:variable>
-
+    
     <!-- $path-to-source should point back to the location of the source catalog (or profile) from its result,
          so '..' is appropriate when writing results down a directory. -->
     <xsl:param name="path-to-source" as="xs:string?"/>
 
     <xsl:variable name="louder" select="$trace = 'on'"/>
 
-    <xsl:param name="home" select="/"/>
+    <xsl:variable name="home" select="/"/>
+
+    <!-- If true, do not record profile URI in output catalog's source-profile
+        metadata, due to privacy or security concerns. -->
+    <xsl:param name="hide-source-profile-uri" as="xs:boolean" select="false()"/>
 
     <!-- The $transformation-sequence declares transformations to be applied in order. -->
     <xsl:variable name="transformation-sequence">
@@ -109,8 +86,10 @@
     <xsl:template mode="opr:provide-parameters" match="opr:transform"/>
     
     <xsl:template mode="opr:provide-parameters" match="opr:transform[.='oscal-profile-resolve-metadata.xsl']">
-        <!-- Since the fallback is not a valid URI the processor will try Java -->
-        <xsl:map-entry key="QName('','assign-uuid')" select="$use-uuid"/>
+        <xsl:map-entry key="QName('','top-uuid-computed')">
+            <xsl:call-template name="u:determine-uuid"/>
+        </xsl:map-entry>
+        <xsl:map-entry key="QName('','hide-source-profile-uri')" select="$hide-source-profile-uri"/>
     </xsl:template>
     
     <!-- for opr:transformation, the semantics are "apply this XSLT" -->
diff --git a/src/utils/util/resolver-pipeline/oscal-profile-resolve-metadata.xsl b/src/utils/util/resolver-pipeline/oscal-profile-resolve-metadata.xsl
index 2f45c909bd..da67371d88 100644
--- a/src/utils/util/resolver-pipeline/oscal-profile-resolve-metadata.xsl
+++ b/src/utils/util/resolver-pipeline/oscal-profile-resolve-metadata.xsl
@@ -6,29 +6,53 @@
     xmlns:xs="http://www.w3.org/2001/XMLSchema"
     xmlns:math="http://www.w3.org/2005/xpath-functions/math"
     xmlns:opr="http://csrc.nist.gov/ns/oscal/profile-resolution"
-    exclude-result-prefixes="xs math o opr"
+    xmlns:u="http://csrc.nist.gov/ns/uuid"
+    exclude-result-prefixes="xs math o opr u"
     xpath-default-namespace="http://csrc.nist.gov/ns/oscal/1.0" >
-
+    
     <!-- XSLT 2.0 so as to validate against XSLT 3.0 constructs -->
+    
+    <!-- How to specify top-level UUID for result catalog:
+
+        a) When oscal-profile-RESOLVE.xsl invokes this transform,
+        it passes in a precomputed value for $top-uuid-computed.
+
+        b) Any other caller of this transform should pass in
+        $uuid-method and, if applicable, $top-uuid and $uuid-service,
+        but not $top-uuid-computed. As a result, this transform
+        will compute $top-uuid-computed.
+        -->
+
+    <!-- uuid-method-choice.xsl has global parameters
+        $uuid-method, $top-uuid, and $uuid-service. -->
+    <xsl:import href="uuid-method-choice.xsl"/>
+
+    <!-- Top-level UUID for result catalog. -->
+    <xsl:param name="top-uuid-computed"  as="xs:string">
+        <xsl:call-template name="u:determine-uuid"/>
+    </xsl:param>
 
     <xsl:param name="profile-origin-uri">urn:UNKNOWN</xsl:param>
 
-    <!-- Accepts a uuid as $assign-uuid, or provides a dummy UUID. A calling application can provide a 'random' UUID.  -->
-    <xsl:param name="assign-uuid"  as="xs:string?"/>
-    
-    <xsl:variable name="uuid-v4-regex" as="xs:string">^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-4[0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}$</xsl:variable>
+    <!-- If true, do not record profile URI in output catalog's source-profile
+        metadata, due to privacy or security concerns. This parameter is
+        passed from oscal-profile-RESOLVE.xsl and the end user can override it. -->
+    <xsl:param name="hide-source-profile-uri" as="xs:boolean" select="false()"/>
     
-    <xsl:variable name="use-uuid" as="xs:string"
-        select="( $assign-uuid[matches(.,$uuid-v4-regex)], '00000000-0000-4000-B000-000000000000' )[1]"/>
-       
-    <xsl:template match="* | @*" mode="#all">
+    <!-- Version of this resolution tool -->
+    <xsl:variable name="tool-oscal-version" as="xs:string" select="'1.1.0'"/>
+
+    <xsl:variable name="source-profile" as="xs:string"
+        select="if ($hide-source-profile-uri) then 'profile' else $profile-origin-uri"/>
+
+    <xsl:template match="/ | * | @*" mode="#all">
         <xsl:copy>
             <xsl:apply-templates mode="#current" select="node() | @*"/>
         </xsl:copy>
     </xsl:template>
 
     <xsl:template match="profile" priority="1">
-        <catalog uuid="{ $use-uuid }">
+        <catalog uuid="{ $top-uuid-computed }">
             <!-- Rewriting top-level @id -->
             <!--<xsl:if test="function-available('uuid:randomUUID')" xmlns:uuid="java:java.util.UUID">
                 <xsl:attribute name="uuid" select="uuid:randomUUID()"/>
@@ -38,12 +62,13 @@
     </xsl:template>
 
     <xsl:template match="profile/metadata">
-        <xsl:variable name="leaders" select="(title | published | last-modified | version | oscal-version | doc-id)"/>
+        <xsl:variable name="leaders" select="(title | published | last-modified | version | oscal-version | document-id)"/>
         <xsl:copy>
             <xsl:apply-templates mode="#current" select="@*"/>
             <xsl:apply-templates mode="#current" select="$leaders"/>
             <xsl:apply-templates mode="#current" select="prop"/>
-            <link href="{$profile-origin-uri}" rel="resolution-source"/>
+            <prop name="resolution-tool" value="OSCAL Profile Resolver XSLT Pipeline OPRXP"/>
+            <link href="{$source-profile}" rel="source-profile"/>
             <xsl:apply-templates mode="#current" select="* except ($leaders | prop)"/>
             <!--<xsl:apply-templates select="../selection" mode="imported-metadata"/>-->
         </xsl:copy>
@@ -55,13 +80,34 @@
         </xsl:copy>
     </xsl:template>
 
+    <xsl:template match="profile/metadata/oscal-version">
+        <xsl:copy>
+            <xsl:sequence select="opr:oscal-version(
+                .,
+                ancestor::profile/selection/metadata/oscal-version/normalize-space(),
+                $tool-oscal-version
+                )"/>
+        </xsl:copy>
+    </xsl:template>
+
+    <!-- If there is a common major version among all inputs,
+        return the most recent minor version or the tool version,
+        whichever is earlier.
+        If there is no common major version, return fatal error. -->
+    <xsl:function name="opr:oscal-version" as="xs:string">
+        <xsl:param name="source" as="xs:string"/>
+        <xsl:param name="imported" as="xs:string*"/>
+        <xsl:param name="tool" as="xs:string"/>
+        <xsl:value-of select="'TODO: Not implemented yet'"/>
+    </xsl:function>
+
     <!--<xsl:template match="selection" mode="imported-metadata">
         <resource id="{@id}-RESOURCE" rel="imported">
             <xsl:copy-of select="metadata/title" copy-namespaces="no"/>
             <rlink href="{@opr:src}"/>
         </resource>
     </xsl:template>-->
-
+    
     <xsl:template match="selection/metadata"/>
-
+    
 </xsl:stylesheet>
diff --git a/src/utils/util/resolver-pipeline/readme.md b/src/utils/util/resolver-pipeline/readme.md
index aa9cadeb67..0e8913a01b 100644
--- a/src/utils/util/resolver-pipeline/readme.md
+++ b/src/utils/util/resolver-pipeline/readme.md
@@ -1,33 +1,49 @@
-## Resolver pipeline
+## Profile Resolver Pipeline
 
-Profile resolution is implemented here as a set of XSLT transformations to be performed in sequence, applied to defined inputs (a **source profile** with imported **catalog** sources) to produce defined outputs (a **profile resolution result** in the form of a catalog). The word **baseline** is also used to refer to a particular profile in application, whether in its unprocessed form or its resolved, serialized form.
+Profile resolution is implemented here as a sequence of XSLT transformations. The sequence applies to defined inputs (a **source profile** with imported **catalog** sources) and produces defined outputs (a **profile resolution result** in the form of a catalog). The word **baseline** also refers to a particular profile in application, whether in its unprocessed form or its resolved, serialized form.
 
-The sequence reflects and roughly corresponds to the three steps in profile resolution described for OSCAL in the [Profile Resolution Specification](https://pages.nist.gov/OSCAL/concepts/processing/profile-resolution/):
+The sequence of XSLT transformations reflects and roughly corresponds to the steps in profile resolution described for OSCAL in the [Profile Resolution Specification](https://pages.nist.gov/OSCAL/concepts/processing/profile-resolution/):
 
-- **selection** (importing catalogs or profiles and selecting controls from them)
+- **selection**: importing catalogs or profiles, and selecting controls from them
 
-- **organization (merging)** i.e. specifying how selected controls are to be organized in representation
+- **organization (merging)**: organizing the selected controls for the output representation
 
-- **modification** - setting parameters and potentially supplementing, amending or editing control text
+- **modification**: setting parameters and potentially supplementing, amending or editing control text
 
-For demonstration, the expected interim results for test files are kept in the testing/\* folders
+### Tests for this Implementation
 
-Note that these interim results are *not always valid to any OSCAL schema* while at the same time they are quite close to OSCAL profile and catalog syntax.
+The `testing/*` folders contain XSpec tests that indicate expected interim results of each XSLT transformation in the sequence.
 
-Testing files for profile resolution in general are kept [with the specification](../../../specifications/profile-resolution). The testing files in this subdirectory are only for this implementation.
+Note that these interim results are *not necessarily valid to any OSCAL schema*, although they are quite close to OSCAL profile and catalog syntax.
 
-### Invoking the XSLT:
+The files in `testing/*` are only for this implementation. Implementation-independent tests and sample files for profile resolution are [with the specification](../../../specifications/profile-resolution).
 
-Use a recent version of Saxon for best results -- although we would also be *very interested* to hear from users of other XSLT engines conformant to the 3.1 family of XML standards (XSLT/XPath/XDM/XQuery).
+### Invoking the XSLT
 
-The main entry point for the transformation pipeline is the dynamic build XSLT called `oscal-profile-RESOLVE.xsl`, which invokes the core transformation steps in sequence, taking the source profile document as primary input. Load Saxon with your document and this stylesheet as follows (for example):
+Use a recent version of Saxon for best results &#8212; although we would also be *very interested* to hear from users of other XSLT engines conformant to the 3.1 family of XML standards (XSLT/XPath/XDM/XQuery).
+
+The entry point for the transformation pipeline is `oscal-profile-RESOLVE.xsl`, which invokes the transformation steps in sequence, taking the source profile document as primary input. Load Saxon with your document and this stylesheet as follows (for example):
 
 ```bash
 >  java -cp saxon-he-10.0.jar net.sf.saxon.Transform -t -s:YOUR_PROFILE_DOCUMENT.xml -xsl:path/to/oscal-profile-RESOLVE.xsl -o:YOUR_RESULT_BASELINE.xml
 ```
 
-Alternatively, set up the bindings in an IDE or programmed environment that has XSLT 3.1 support.
+You can optionally set one or more of the parameters listed in the following table, using syntax `name=value` at the end of the command above. The sequence of parameters is not significant.
+
+For example,
+```bash
+>  java -cp saxon-he-10.0.jar net.sf.saxon.Transform -t -s:YOUR_PROFILE_DOCUMENT.xml -xsl:path/to/oscal-profile-RESOLVE.xsl -o:YOUR_RESULT_BASELINE.xml uuid-method=random-xslt hide-source-profile-uri=true
+```
+| Name  | Description  | Default  |
+|---|---|---|
+| `hide-source-profile-uri` | If `true`, the output catalog's metadata does not record the source profile's URI.  | `false` |
+| `path-to-source`  | Path from output catalog to location of source profile. | None |
+| `top-uuid` | UUID value for top-level element in output catalog, if `uuid-method` is `user-provided`. | None |
+| `uuid-method` | Method for computing UUID of top-level element in output catalog. Valid values are: `random-xslt`, in which case the `random-number-generator` XPath function must be available; `random-java`, in which case the `java.util.UUID.randomUUID()` Java method must be available; `user-provided`, in which case you must specify the `top-uuid` parameter; `web-service`, referring to the `uuid-service` parameter value; and `fixed`. | `fixed`|
+| `uuid-service` | URI for a web service that produces a UUID, if `uuid-method` is `web-service`.| `https://www.uuidgenerator.net/api/version4`|
+
+Alternatively, set up the bindings in an IDE or programming environment that has XSLT 3.1 support.
 
-Note that URIs (addresses) given in a profile document must link correctly as absolute or relative paths to their imported catalogs, as demonstrated in examples.
+Note that URIs (addresses) given in a profile document must link correctly as absolute or relative paths to their imported catalogs, as demonstrated in [examples](../../../specifications/profile-resolution/profile-resolution-examples).
 
-A captured and serialized profile resolution will take the form of an OSCAL catalog, and be valid to the catalog schema for correctly formed inputs.
+A serialized output of profile resolution takes the form of an OSCAL catalog. Assuming inputs are correctly formed, the output is valid to the catalog schema.
diff --git a/src/utils/util/resolver-pipeline/testing/2_metadata/metadata.xspec b/src/utils/util/resolver-pipeline/testing/2_metadata/metadata.xspec
index a670f3b298..2cb9d2fade 100644
--- a/src/utils/util/resolver-pipeline/testing/2_metadata/metadata.xspec
+++ b/src/utils/util/resolver-pipeline/testing/2_metadata/metadata.xspec
@@ -1,162 +1,359 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <x:description
-    xmlns="http://csrc.nist.gov/ns/oscal/1.0" xmlns:x="http://www.jenitennison.com/xslt/xspec"
+    xmlns="http://csrc.nist.gov/ns/oscal/1.0"    
+    xmlns:o="http://csrc.nist.gov/ns/oscal/1.0"
+    xmlns:opr="http://csrc.nist.gov/ns/oscal/profile-resolution"
+    xmlns:ov="http://csrc.nist.gov/ns/oscal/xspec/variable"
+    xmlns:x="http://www.jenitennison.com/xslt/xspec"
+    xmlns:xs="http://www.w3.org/2001/XMLSchema"
+    run-as="external"
     stylesheet="../../oscal-profile-resolve-metadata.xsl">
-    <x:scenario label="Base">
-        <x:context>
-            <profile uuid="test"/>
-        </x:context>
-
-        <x:expect label="profile becomes catalog">
-            <catalog uuid="..."/>
-        </x:expect>
-    </x:scenario>
+    
+    <!-- In this file, the purpose of run-as="external" is to enable
+        individual scenarios to specify values of global XSLT
+        parameters. -->
 
-    <x:scenario label="floor">
-        <x:context>
-            <profile uuid="test">
+    <x:variable name="ov:sample-output-from-pipeline-step-1" as="element(o:profile)">
+        <profile uuid="cb1ec926-3441-458f-8cce-ea11308c9d37">
+            <metadata>
+                <title>Test Profile</title>
+                <last-modified>2021-05-30T14:39:35.84-04:00</last-modified>
+                <version>1.3</version>
+                <oscal-version>1.0.1</oscal-version>
+            </metadata>
+            <selection uuid="6498eb6e-8653-4470-8b97-54054d3ba886" opr:src="some-value">
                 <metadata>
-                    <title>Small Profile for Testing</title>
-                    <last-modified>2019-11-13T12:13:58.517-05:00</last-modified>
+                    <title>XYZ Tiny Catalog</title>
+                    <last-modified>2020-05-30T14:51:42.355-04:00</last-modified>
                     <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
+                    <oscal-version>1.0.0</oscal-version>
+                    <prop name="catalog-required" value="some value"/>
+                    <link href="#catalog-internal"><text>Internal link within catalog</text></link>
                 </metadata>
-            </profile>
-        </x:context>
+                <group opr:id="some-id">
+                    <title>Group X of XYZ</title>
+                </group>
+            </selection>
+        </profile>
+    </x:variable>
 
-        <x:expect label="profile becomes catalog">
-            <catalog uuid="...">
-                <metadata>
-                    <title>Small Profile for Testing</title>
-                    <last-modified>...</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
-                    <link href="urn:UNKNOWN" rel="resolution-source"/>
-                </metadata>
-            </catalog>
-        </x:expect>
+    <x:scenario label="Tests for match='/ | * | @*' template for all modes">
+        <x:variable name="ov:arbitrary-element" as="element(arbitrary-element)">
+            <arbitrary-element xmlns="" arbitrary-attribute="val">text<child/></arbitrary-element>
+        </x:variable>
+        <x:scenario label="Element">
+            <x:context select="$ov:arbitrary-element"/>
+            <x:expect label="Copy" select="$ov:arbitrary-element"/>
+        </x:scenario>
+        <x:scenario label="Attribute">
+            <x:context select="$ov:arbitrary-element/@arbitrary-attribute"/>
+            <x:expect label="Copy"
+                test="$x:result instance of attribute(arbitrary-attribute) and $x:result/string()='val'"/>
+        </x:scenario>
     </x:scenario>
-    <x:scenario label="enhance metadata">
+
+    <x:scenario label="Tests for match=profile template">
+        <x:variable name="ov:top-uuid" as="xs:string"
+            select="'12345678-90AB-4CDE-a012-bcdef0123456'"/>
+        <x:param name="profile-origin-uri" select="'urn:UNKNOWN/some-profile-filename.xml'"/>
         <x:context>
-            <profile uuid="pathological-profile">
+            <profile uuid="test"/>
+        </x:context>
+        <x:scenario label="Basic case">
+            <x:param name="top-uuid" select="$ov:top-uuid"/>
+            <x:param name="uuid-method" select="'user-provided'"/>
+            <x:expect label="Catalog uses specified uuid"
+                test="/o:catalog/@uuid/string()" select="$ov:top-uuid"/>
+        </x:scenario>
+        <x:scenario label="selection/metadata has prop and link children">
+            <x:context select="$ov:sample-output-from-pipeline-step-1"/>            
+            <x:expect label="Source catalog prop does not leak into output catalog metadata"
+                test="exists(/o:catalog/o:metadata) and
+                empty(/o:catalog/o:metadata/o:prop[@name='catalog-required'])"/>
+            <x:expect label="Source catalog link does not leak into output catalog metadata"
+                test="exists(/o:catalog/o:metadata) and
+                empty(/o:catalog/o:metadata/o:link[@href='#catalog-internal'])"/>
+        </x:scenario>
+    </x:scenario>
+
+    <x:scenario label="Tests for match=profile/metadata template">
+        <x:scenario label="Simple case">
+            <x:context select="$ov:sample-output-from-pipeline-step-1/o:metadata"/>
+            <x:expect label="Metadata includes profile version, resolution-tool prop, and source-profile link">
                 <metadata>
-                    <title>Pathological Profile</title>
-                    <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
+                    <title>Test Profile</title>
+                    <last-modified>...</last-modified>
+                    <version>1.3</version>
+                    <oscal-version>...</oscal-version>
+                    <prop name="resolution-tool" value="OSCAL Profile Resolver XSLT Pipeline OPRXP" />
+                    <link href="urn:UNKNOWN" rel="source-profile" />
                 </metadata>
-                <selection uuid="abc-full_catalog">
+            </x:expect>
+            <x:expect label="version value matches version of source profile"
+                test="/o:metadata/o:version/string()" select="'1.3'"/>
+        </x:scenario>
+        <x:scenario label="profile/metadata has additional children, 'leader' and others">
+            <x:context select="/o:profile/o:metadata">
+                <profile uuid="pathological-profile">
                     <metadata>
-                        <title>ABC Catalog</title>
-                        <last-modified>2019-11-01T10:16:22.939-04:00</last-modified>
+                        <title>Pathological Profile</title>
+                        <published>2019-11-13T12:41:07.061-05:00</published>
+                        <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
                         <version>1.0</version>
                         <oscal-version>1.0-rc2</oscal-version>
+                        <document-id scheme="https://www.doi.org/">...doi...</document-id>
+                        <party>
+                            <org>
+                                <org-name>Standing Committee</org-name>
+                            </org>
+                        </party>
                     </metadata>
-                </selection>
-            </profile>
-        </x:context>
-
-        <x:expect label="title amended, with properties and link added">
-            <catalog uuid="...">
+                </profile>
+            </x:context>            
+            <x:expect label="resolution-tool and source-profile are between last 'leader' (document-id) and 'everything else' (party)">
                 <metadata>
-                    <title>Pathological Profile</title>
+                    <title>...</title>
+                    <published>2019-11-13T12:41:07.061-05:00</published>
                     <last-modified>...</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
-                    <link href="urn:UNKNOWN"
-                        rel="resolution-source"/>
-                </metadata>
-                <selection uuid="abc-full_catalog"/>
-            </catalog>
-        </x:expect>
-    </x:scenario>
-    <x:scenario label="place link correctly">
-        <x:context>
-            <profile uuid="pathological-profile">
-                <metadata>
-                    <title>Pathological Profile</title>
-                    <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
+                    <version>...</version>
+                    <oscal-version>...</oscal-version>
+                    <document-id scheme="https://www.doi.org/">...doi...</document-id>
+                    <prop name="resolution-tool" value="..."/>
+                    <link href="urn:UNKNOWN" rel="source-profile"/>
                     <party>
                         <org>
                             <org-name>Standing Committee</org-name>
                         </org>
                     </party>
                 </metadata>
-                <selection uuid="abc-full_catalog">
+            </x:expect>
+        </x:scenario>
+        <x:scenario label="profile/metadata has prop child">
+            <x:context select="/o:profile/o:metadata">
+                <profile uuid="pathological-profile">
                     <metadata>
-                        <title>ABC Catalog</title>
-                        <last-modified>2019-11-01T10:16:22.939-04:00</last-modified>
+                        <title>Pathological Profile</title>
+                        <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
                         <version>1.0</version>
                         <oscal-version>1.0-rc2</oscal-version>
+                        <prop name="required" value="some value"/>
+                        <prop name="optional" value="some other value"/>
                     </metadata>
-                </selection>
-            </profile>
-        </x:context>
-
-        <x:expect label="title amended, link added before party">
-            <catalog uuid="...">
+                </profile>
+            </x:context>            
+            <x:expect label="resolution-tool prop is after last prop from input">
                 <metadata>
-                    <title>Pathological Profile</title>
+                    <title>...</title>
                     <last-modified>...</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
-                    <link href="urn:UNKNOWN" rel="resolution-source"/>
-                    <party>
-                        <org>
-                            <org-name>Standing Committee</org-name>
-                        </org>
-                    </party>
-                </metadata>
-                <selection uuid="abc-full_catalog"/>
-            </catalog>
-        </x:expect>
-    </x:scenario>
-    <x:scenario label="place link correctly with another link">
-        <x:context>
-            <profile uuid="pathological-profile">
-                <metadata>
-                    <title>Pathological Profile</title>
-                    <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
-                    <link href="#internal"><text>Internal link</text></link>
-                    <party>
-                        <org>
-                            <org-name>Standing Committee</org-name>
-                        </org>
-                    </party>
+                    <version>...</version>
+                    <oscal-version>...</oscal-version>
+                    <prop name="required" value="some value"/>
+                    <prop name="optional" value="some other value"/>
+                    <prop name="resolution-tool" value="..."/>
+                    <link href="..." rel="source-profile"/>
                 </metadata>
-                <selection uuid="abc-full_catalog">
+            </x:expect>
+        </x:scenario>
+        <x:scenario label="profile/metadata has link">
+            <x:context select="/o:profile/o:metadata">
+                <profile uuid="pathological-profile">
                     <metadata>
-                        <title>ABC Catalog</title>
-                        <last-modified>2019-11-01T10:16:22.939-04:00</last-modified>
+                        <title>Pathological Profile</title>
+                        <last-modified>2019-11-13T12:41:07.061-05:00</last-modified>
                         <version>1.0</version>
                         <oscal-version>1.0-rc2</oscal-version>
+                        <link href="#internal"><text>Internal link</text></link>
                     </metadata>
-                </selection>
-            </profile>
-        </x:context>
-
-        <x:expect label="title amended, link added before old link">
-            <catalog uuid="...">
+                </profile>
+            </x:context>
+            <x:expect label="source-profile link is inserted before copied link">
                 <metadata>
-                    <title>Pathological Profile</title>
+                    <title>...</title>
                     <last-modified>...</last-modified>
-                    <version>1.0</version>
-                    <oscal-version>1.0-rc2</oscal-version>
-                    <link href="urn:UNKNOWN" rel="resolution-source"/>
+                    <version>...</version>
+                    <oscal-version>...</oscal-version>
+                    <prop name="resolution-tool" value="..."/>
+                    <link href="..." rel="source-profile"/>
                     <link href="#internal"><text>Internal link</text></link>
-                    <party>
-                        <org>
-                            <org-name>Standing Committee</org-name>
-                        </org>
-                    </party>
                 </metadata>
-                <selection uuid="abc-full_catalog"/>
-            </catalog>
-        </x:expect>
+            </x:expect>
+        </x:scenario>
+        <x:scenario label="Option to hide source profile URI">
+            <x:param name="hide-source-profile-uri" select="true()"/>
+            <x:context select="$ov:sample-output-from-pipeline-step-1/o:metadata"/>
+            <x:expect label="link rel=source-profile has generic href value"
+                test="//o:link[@rel='source-profile']">
+                <link href="profile" rel="source-profile"/>
+            </x:expect>
+        </x:scenario>
+    </x:scenario>
+
+    <x:scenario label="Tests for match=last-modified template">
+        <x:scenario label="Typical case">
+            <x:context select="$ov:sample-output-from-pipeline-step-1/o:metadata/o:last-modified"/>
+            <x:expect label="last-modified element without attributes">
+                <last-modified>...</last-modified>
+            </x:expect>
+            <x:expect label="Element content is a time stamp"
+                test="$x:result/node() castable as xs:dateTime"/>
+            <!-- last-modified content must represent the time the profile resolution
+                completed. Sanity-check that last-modified is not a copy of the
+                last-modified timestamps from the input document. -->
+            <x:variable name="ov:inputs-last-modified" as="xs:string+"
+                select="$ov:sample-output-from-pipeline-step-1//o:last-modified/string()"/>
+            <x:expect label="last-modified content is not from input document"
+                test="not(o:metadata/o:last-modified/string() = $ov:inputs-last-modified)"/>
+        </x:scenario>
+        <x:scenario label="Empty last-modified in source document">
+            <x:context>
+                <last-modified/>
+            </x:context>
+            <x:expect label="Output still has a time stamp"
+                test="$x:result/self::o:last-modified/node() castable as xs:dateTime"/>
+        </x:scenario>
+    </x:scenario>
+
+    <x:scenario label="Tests for match=profile/metadata/oscal-version template">
+        <x:scenario label="Simple case">
+            <x:context select="/o:profile/o:metadata/o:oscal-version">
+                <profile>
+                    <metadata>
+                        <oscal-version>1.3</oscal-version>
+                    </metadata>
+                </profile>
+            </x:context>
+            <x:expect label="oscal-version">
+                <oscal-version>...</oscal-version>
+            </x:expect>
+        </x:scenario>
+        <x:scenario label="Sanity checks for calling opr:oscal-version with correct inputs: " pending="opr:oscal-version not implemented yet">
+            <x:scenario label="Most recent version is in selection metadata">
+                <x:context select="/o:profile/o:metadata/o:oscal-version">
+                    <profile>
+                        <metadata>
+                            <oscal-version>1.0.3</oscal-version>
+                        </metadata>
+                        <!-- All selections from pipeline's step 1 output
+                            are under consideration, not just first or last. -->
+                        <selection>
+                            <metadata>
+                                <oscal-version>1.0.1</oscal-version>
+                            </metadata>
+                        </selection>
+                        <selection>
+                            <metadata>
+                                <oscal-version>1.0.4</oscal-version>
+                            </metadata>
+                        </selection>
+                        <selection>
+                            <metadata>
+                                <oscal-version>1.0.2</oscal-version>
+                            </metadata>
+                        </selection>
+                    </profile>
+                </x:context>
+                <x:expect label="Most recent minor version mentioned in document">
+                    <oscal-version>1.0.4</oscal-version>
+                </x:expect>
+            </x:scenario>
+            <x:scenario label="Most recent version is in profile metadata">
+                <x:context select="/o:profile/o:metadata/o:oscal-version">
+                    <profile>
+                        <metadata>
+                            <oscal-version>1.0.4</oscal-version>
+                        </metadata>
+                        <selection>
+                            <metadata>
+                                <oscal-version>1.0.1</oscal-version>
+                            </metadata>
+                        </selection>
+                    </profile>
+                </x:context>
+                <x:expect label="Most recent minor version mentioned in document">
+                    <oscal-version>1.0.4</oscal-version>
+                </x:expect>
+            </x:scenario>
+            <x:scenario label="Tool version is older than document versions">
+                <x:context select="/o:profile/o:metadata/o:oscal-version">
+                    <profile>
+                        <metadata>
+                            <oscal-version>1.4.0</oscal-version>
+                        </metadata>
+                        <selection>
+                            <metadata>
+                                <oscal-version>1.2.0</oscal-version>
+                            </metadata>
+                        </selection>
+                    </profile>
+                </x:context>
+                <x:expect label="Tool version">
+                    <oscal-version>1.1.0</oscal-version>
+                </x:expect>
+            </x:scenario>
+        </x:scenario>
+    </x:scenario>
+
+    <x:scenario label="Tests for opr:oscal-version function" pending="opr:oscal-version not implemented yet">
+        <x:scenario label="Same major version">
+            <x:scenario label="Source profile version newer than imported document">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'1.0.1'"/>
+                    <x:param name="imported" select="('1.0.0','1.0.0')"/>
+                    <x:param name="tool" select="'1.0.1'"/>
+                </x:call>
+                <x:expect label="Newest minor version" select="'1.0.1'"/>
+            </x:scenario>
+            <x:scenario label="Source profile version older than imported document">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'1.0.0'"/>
+                    <x:param name="imported" select="('1.0.1','1.0.1')"/>
+                    <x:param name="tool" select="'1.0.1'"/>
+                </x:call>
+                <x:expect label="Newest minor version" select="'1.0.1'"/>
+            </x:scenario>
+            <x:scenario label="Tool version is older">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'1.0.1'"/>
+                    <x:param name="imported" select="('1.0.1','1.0.1')"/>
+                    <x:param name="tool" select="'1.0.0'"/>
+                </x:call>
+                <x:expect label="Tool version" select="'1.0.0'"/>
+            </x:scenario>
+        </x:scenario>
+        <x:scenario label="Different major version">
+            <x:scenario label="Source profile version newer than imported document">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'2.0.1'"/>
+                    <x:param name="imported" select="('1.0.0','1.0.0')"/>
+                    <x:param name="tool" select="'2.0.1'"/>
+                </x:call>
+                <x:expect label="Error"
+                    test="$x:result instance of map(*) and $x:result('err') instance of map(*)"/>
+            </x:scenario>
+            <x:scenario label="Source profile version older than imported document">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'1.0.0'"/>
+                    <x:param name="imported" select="('2.0.1','2.0.1')"/>
+                    <x:param name="tool" select="'2.0.1'"/>
+                </x:call>
+                <x:expect label="Error"
+                    test="$x:result instance of map(*) and $x:result('err') instance of map(*)"/>
+            </x:scenario>
+            <x:scenario label="Tool version is older">
+                <x:call function="opr:oscal-version">
+                    <x:param name="source" select="'2.0.1'"/>
+                    <x:param name="imported" select="('2.0.1','2.0.1')"/>
+                    <x:param name="tool" select="'1.0.0'"/>
+                </x:call>
+                <x:expect label="Error"
+                    test="$x:result instance of map(*) and $x:result('err') instance of map(*)"/>
+            </x:scenario>
+        </x:scenario>
+    </x:scenario>
+    
+    <x:scenario label="Tests for match=selection/metadata template">
+        <x:context select="$ov:sample-output-from-pipeline-step-1//o:selection/o:metadata"/>
+        <x:expect label="Nothing" select="()"/>
     </x:scenario>
 
 </x:description>
diff --git a/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-method-choice.xspec b/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-method-choice.xspec
new file mode 100644
index 0000000000..f1a5f6b8e3
--- /dev/null
+++ b/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-method-choice.xspec
@@ -0,0 +1,86 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<x:description xmlns:x="http://www.jenitennison.com/xslt/xspec"
+    xmlns:ov="http://csrc.nist.gov/ns/oscal/xspec/variable"
+    xmlns:u="http://csrc.nist.gov/ns/uuid"
+    xmlns:xs="http://www.w3.org/2001/XMLSchema"
+    stylesheet="../../uuid-method-choice.xsl">
+    
+    <x:scenario label="Tests for u:determine-uuid template">
+        <x:variable name="ov:fixed" as="xs:string" select="'00000000-0000-4000-B000-000000000000'"/>
+        <x:variable name="ov:specified" as="xs:string" select="'f0ad1e6c-5de5-44cd-b92e-a4c507805f0f'"/>
+        <x:variable name="ov:service" as="xs:string" select="resolve-uri('../uuid-value.txt')"/>
+        <x:scenario label="Valid user-provided UUID">
+            <x:call template="u:determine-uuid">
+                <x:param name="top-uuid" select="$ov:specified"/>
+                <x:param name="uuid-method" select="'user-provided'"/>
+            </x:call>
+            <x:expect label="Specified UUID" select="$ov:specified"/>
+        </x:scenario>
+        <x:scenario label="Invalid user-provided UUID">
+            <x:call template="u:determine-uuid">
+                <x:param name="top-uuid" select="'123'"/>
+                <x:param name="uuid-method" select="'user-provided'"/>
+            </x:call>
+            <x:expect label="Fixed UUID" select="$ov:fixed"/>
+        </x:scenario>
+        <x:scenario label="Random UUID using XSLT">
+            <!-- Random XSLT method requires a global context item.
+                For this test's purpose, the context item does not
+                matter, so just use this file itself. -->
+            <x:context href="uuid-method-choice.xspec"/>
+            <x:call template="u:determine-uuid">
+                <x:param name="top-uuid" select="$ov:specified"/>
+                <x:param name="uuid-method" select="'random-xslt'"/>
+            </x:call>
+            <x:expect label="Nonempty string"
+                test="$x:result instance of xs:string and $x:result != ''"/>
+            <x:expect label="UUID is neither fixed one nor specified one"
+                test="$x:result ne $ov:specified and $x:result ne $ov:fixed"/>
+        </x:scenario>
+        <x:scenario label="Random UUID using Java">
+            <x:call template="u:determine-uuid">
+                <x:param name="top-uuid" select="$ov:specified"/>
+                <x:param name="uuid-method" select="'random-java'"/>
+            </x:call>
+            <x:expect label="Nonempty string"
+                test="$x:result instance of xs:string and $x:result != ''"/>
+            <x:expect label="UUID is neither fixed one nor specified one"
+                test="$x:result ne $ov:specified and $x:result ne $ov:fixed"/>
+        </x:scenario>
+        <!-- FYI: Because the transform relies on use-when, which is evaluated at
+            compile time, the same test invocation cannot check both
+            when the XSLT and Java random number generators are available
+            and when they are unavailable. This XSpec test does not cover
+            the fallback behavior that produces the fixed UUID value. -->
+        <x:scenario label="web-service method, available">
+            <!-- To avoid having the test require access to the Internet,
+                mock the web service as a text file that XSLT reads using
+                unparsed-text(). -->
+            <x:call template="u:determine-uuid">
+                <x:param name="uuid-service" select="$ov:service"/>
+                <x:param name="uuid-method" select="'web-service'"/>
+            </x:call>
+            <x:expect label="Value from the 'web service' (in this case, a text file)"
+                select="'309deb03-491b-4677-9148-bc1b79a21c9c'"/>
+        </x:scenario>
+        <x:scenario label="web-service method, unavailable">
+            <x:call template="u:determine-uuid">
+                <x:param name="uuid-service" select="'nonexistent.txt'"/>
+                <x:param name="uuid-method" select="'web-service'"/>
+            </x:call>
+            <x:expect label="Fixed UUID" select="$ov:fixed"/>
+        </x:scenario>
+        <x:scenario label="Fixed UUID">
+            <x:call template="u:determine-uuid">
+                <x:param name="uuid-method" select="'fixed'"/>
+            </x:call>
+            <x:expect label="Fixed UUID" select="$ov:fixed"/>
+        </x:scenario>
+        <x:scenario label="Unrecognized method">
+            <x:call template="u:determine-uuid">
+                <x:param name="uuid-method" select="'junk'"/>
+            </x:call>
+            <x:expect label="Fixed UUID" select="$ov:fixed"/>
+        </x:scenario>
+    </x:scenario>
+</x:description>
diff --git a/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-value.txt b/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-value.txt
new file mode 100644
index 0000000000..a8e02be099
--- /dev/null
+++ b/src/utils/util/resolver-pipeline/testing/2_metadata/uuid-value.txt
@@ -0,0 +1 @@
+309deb03-491b-4677-9148-bc1b79a21c9c
\ No newline at end of file
diff --git a/src/utils/util/resolver-pipeline/uuid-method-choice.xsl b/src/utils/util/resolver-pipeline/uuid-method-choice.xsl
new file mode 100644
index 0000000000..97c028fb55
--- /dev/null
+++ b/src/utils/util/resolver-pipeline/uuid-method-choice.xsl
@@ -0,0 +1,89 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<xsl:stylesheet
+    xmlns:javaUUID="java.util.UUID"
+    xmlns:mh="http://csrc.nist.gov/ns/message"
+    xmlns:r="http://csrc.nist.gov/ns/random"
+    xmlns:u="http://csrc.nist.gov/ns/uuid"
+    xmlns:xsl="http://www.w3.org/1999/XSL/Transform"
+    xmlns:xs="http://www.w3.org/2001/XMLSchema"
+    exclude-result-prefixes="#all"
+    version="3.0">
+
+    <xsl:import href="random-util.xsl"/>
+    <xsl:import href="message-handler.xsl"/>
+
+    <!-- Select an approach for assigning the top-level UUID for the 
+        result catalog. Supported values:
+        - 'random-xslt'    No parameters.
+        - 'random-java'    No parameters.
+        - 'user-provided'  Parameter $top-uuid is required in this case.
+        - 'web-service'    Parameter $uuid-service is optional.
+        - 'fixed'          No parameters.
+        -->
+    <xsl:param name="uuid-method" as="xs:string" select="'fixed'"/>
+    
+    <!-- Explicit top-level UUID for the result catalog. -->
+    <xsl:param name="top-uuid" as="xs:string?"/>
+    
+    <!-- Alternatively, call a web service if the processor supports it -->
+    <xsl:param name="uuid-service" select="'https://www.uuidgenerator.net/api/version4'"/>
+
+    <xsl:template name="u:determine-uuid" as="xs:string">
+        <xsl:param name="uuid-method" select="$uuid-method" as="xs:string"/>
+        <xsl:param name="uuid-service" select="$uuid-service" as="xs:string"/>
+        <xsl:param name="top-uuid" select="$top-uuid" as="xs:string?"/>
+        
+        <xsl:variable name="uuid-v4-regex" as="xs:string">^[0-9A-Fa-f]{8}-[0-9A-Fa-f]{4}-4[0-9A-Fa-f]{3}-[89ABab][0-9A-Fa-f]{3}-[0-9A-Fa-f]{12}$</xsl:variable>
+        <xsl:variable name="fixed-uuid" as="xs:string">00000000-0000-4000-B000-000000000000</xsl:variable>
+        <xsl:choose>
+            <xsl:when test="$uuid-method eq 'user-provided' and
+                matches($top-uuid,$uuid-v4-regex)">
+                <xsl:sequence select="$top-uuid"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'user-provided'">
+                <!-- If we reach this block, the provided value does not match the regex. -->
+                <xsl:call-template name="mh:message-handler">
+                    <xsl:with-param name="message-type">Warning</xsl:with-param>
+                    <xsl:with-param name="text" expand-text="yes">top-uuid value, '{$top-uuid}', does not meet UUID requirements. Using default UUID instead.</xsl:with-param>
+                </xsl:call-template>
+                <xsl:sequence select="$fixed-uuid"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'random-xslt'" use-when="function-available('random-number-generator')">
+                <!-- seed splices a timestamp with a given @uuid -->
+                <xsl:sequence select="r:make-uuid( /*/@uuid || '-' || replace( string(current-dateTime()),'\D','') )"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'random-java'" use-when="function-available('javaUUID:randomUUID')">
+                <xsl:sequence select="javaUUID:randomUUID()"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method = ('random-xslt','random-java')">
+                <!-- If we reach this block, the requested random method is not available. -->
+                <xsl:call-template name="mh:message-handler">
+                    <xsl:with-param name="message-type">Warning</xsl:with-param>
+                    <xsl:with-param name="text" expand-text="yes">uuid-method, '{$uuid-method}', is not available. Using default UUID instead.</xsl:with-param>
+                </xsl:call-template>
+                <xsl:sequence select="$fixed-uuid"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'web-service' and unparsed-text-available($uuid-service)">
+                <xsl:sequence select="unparsed-text($uuid-service)"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'web-service'">
+                <xsl:call-template name="mh:message-handler">
+                    <xsl:with-param name="message-type">Warning</xsl:with-param>
+                    <xsl:with-param name="text" expand-text="yes">uuid-service, '{$uuid-service}', is not available. Using default UUID instead.</xsl:with-param>
+                </xsl:call-template>
+                <xsl:sequence select="$fixed-uuid"/>
+            </xsl:when>
+            <xsl:when test="$uuid-method eq 'fixed'">
+                <xsl:sequence select="$fixed-uuid"/>
+            </xsl:when>
+            <xsl:otherwise>
+                <xsl:call-template name="mh:message-handler">
+                    <xsl:with-param name="message-type">Warning</xsl:with-param>
+                    <xsl:with-param name="text" expand-text="yes">uuid-method, '{$uuid-method}', is not recognized. Using default UUID instead.</xsl:with-param>
+                </xsl:call-template>
+                <xsl:sequence select="$fixed-uuid"/>
+            </xsl:otherwise>
+        </xsl:choose>
+    </xsl:template>
+
+</xsl:stylesheet>
\ No newline at end of file