code for review update

app/Library/Xml/DatasetExtension.php

@@ -43,7 +43,7 @@ trait DatasetExtension
             'pivot' => array('role' => 'author'),
                             //'sort_order' => array('sort_order' => 'ASC'),   // <-- We need a sorted authors list.
             //'sort_field' => 'SortOrder',
-            'relation' => 'authors',
+            'relation' => 'persons',
             'fetch' => 'eager'
         ),
         'PersonContributor' => array(
@@ -52,7 +52,7 @@ trait DatasetExtension
             'pivot' => array('role' => 'contributor'),
             //                'sort_order' => array('sort_order' => 'ASC'),   // <-- We need a sorted authors list.
             //'sort_field' => 'SortOrder',
-            'relation' => 'contributors',
+            'relation' => 'persons',
             'fetch' => 'eager'
         ),
         'Subject' => array(
@@ -85,14 +85,9 @@ trait DatasetExtension
     {
         $fields = array(
             "Id",
-            "CompletedDate", "CompletedYear",
             "ContributingCorporation",
             "CreatingCorporation",
-            "ThesisDateAccepted", "ThesisYearAccepted",
-            "Edition",
-            "Issue",
             "Language",
-            "PageFirst", "PageLast", "PageNumber",
             "PublishedDate", "PublishedYear",
             "PublisherName", "PublisherPlace",
             "PublicationState",
@@ -102,7 +97,6 @@ trait DatasetExtension
             "ServerDateDeleted",
             "ServerState",
             "Type",
-            "Volume",
             "BelongsToBibliography",
             "EmbargoDate"
         );
@@ -121,7 +115,7 @@ trait DatasetExtension
              // Initialize available date fields and set up date validator
             // if the particular field is present
         $dateFields = array(
-            'ServerDateCreated', 'CompletedDate', 'PublishedDate',
+            'ServerDateCreated', 'PublishedDate',
             'ServerDateModified', 'ServerDatePublished', 'ServerDateDeleted', 'EmbargoDate'
         );
         foreach ($dateFields as $fieldName) {

app/Library/Xml/Strategy.php

@@ -70,6 +70,37 @@ class Strategy
         return $this->_config->dom;
     }
 
+    public function getModelFieldValues(Dataset $model)
+    {
+        $fields = $model->describe();
+        $excludeFields = $this->getConfig()->excludeFields;
+        if (count($excludeFields) > 0) {
+            $fieldsDiff = array_diff($fields, $excludeFields);
+        } else {
+            $fieldsDiff = $fields;
+        }
+
+        foreach ($fieldsDiff as $fieldname) {
+            $field = $model->getField($fieldname);
+            $fieldValue = $this->getFieldValue($field);
+        }
+    }
+
+    protected function getFieldValue(Field $field): string
+    {
+        $modelClass = $field->getValueModelClass();
+        $fieldValues = $field->getValue();
+      
+        if (null === $modelClass) {
+            $fieldName = $field->getName();
+            $fieldValues = $this->getFieldValues($field);
+    
+            // Replace invalid XML-1.0-Characters by UTF-8 replacement character.
+            $fieldValues = preg_replace('/[\x00-\x08\x0B\x0C\x0E-\x1F\x7F]/', "\xEF\xBF\xBD ", $fieldValues);
+        }
+        return fieldValues;
+    }
+
     protected function _mapModel(Dataset $model, \DOMDocument $dom, \DOMNode $rootNode)
     {
         $fields = $model->describe();

app/Library/Xml/XmlModel.php

@@ -126,7 +126,7 @@ class XmlModel
             return $domDocument;
         }
 
-        //create xml:
+        //$domDocument == null -> create xml:
         $domDocument = $this->strategy->getDomDocument();
         //if caching is not desired, return domDocument
         if (is_null($this->cache)) {