Add own exception namespace

Exceptions from this library all extend the IIIFException - so a simple
instance of query is simpler.

Exception/DataException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Subugoe\IIIFBundle\Exception;
+
+class DataException extends IIIFException
+{
+}

Exception/IIIFException.php

@@ -0,0 +1,7 @@
+<?php
+
+namespace Subugoe\IIIFBundle\Exception;
+
+class IIIFException extends \Exception
+{
+}

Exception/MalformedDocumentException.php

@@ -2,6 +2,6 @@
 
 namespace Subugoe\IIIFBundle\Exception;
 
-class MalformedDocumentException extends \Exception
+class MalformedDocumentException extends IIIFException
 {
 }

Service/PresentationService.php

@@ -4,6 +4,7 @@
 
 namespace Subugoe\IIIFBundle\Service;
 
+use Subugoe\IIIFBundle\Exception\DataException;
 use Subugoe\IIIFBundle\Exception\MalformedDocumentException;
 use Subugoe\IIIFBundle\Model\LogicalStructure;
 use Subugoe\IIIFBundle\Model\PhysicalStructure;
@@ -501,7 +502,11 @@ private function getPreviousHierarchyStructure(\Subugoe\IIIFBundle\Model\Documen
             }
         }
 
-        throw new \Exception('Parent structure not defined');
+        throw new DataException(vsprintf(
+            'Parent structure at position %d with level %d and parent level %d not defined', [
+                $position, $level, $parentLevel,
+            ]
+        ), 1494506264);
     }
 
     /**