Replace string class names with the ::class attribute.

src/Mapper/Layer/GroupLayerMapper.php

@@ -17,6 +17,7 @@ use Netzmacht\Contao\Leaflet\Mapper\DefinitionMapper;
 use Netzmacht\Contao\Leaflet\Model\LayerModel;
 use Netzmacht\Contao\Leaflet\Request\Request;
 use Netzmacht\LeafletPHP\Definition;
+use Netzmacht\LeafletPHP\Definition\Group\FeatureGroup;
 use Netzmacht\LeafletPHP\Definition\Group\LayerGroup;
 use Netzmacht\LeafletPHP\Definition\Layer;
 
@@ -40,10 +41,10 @@ class GroupLayerMapper extends AbstractLayerMapper
     protected function getClassName(Model $model, DefinitionMapper $mapper, Request $request = null)
     {
         if ($model->groupType === 'feature') {
-            return 'Netzmacht\LeafletPHP\Definition\Group\FeatureGroup';
+            return FeatureGroup::class;
         }
 
-        return 'Netzmacht\LeafletPHP\Definition\Group\LayerGroup';
+        return LayerGroup::class;
     }
 
     /**

src/Mapper/Layer/MarkerClusterLayerMapper.php

@@ -36,7 +36,7 @@ class MarkerClusterLayerMapper extends AbstractLayerMapper
      *
      * @var string
      */
-    protected static $definitionClass = 'Netzmacht\LeafletPHP\Plugins\MarkerCluster\MarkerClusterGroup';
+    protected static $definitionClass = MarkerClusterGroup::class;
 
     /**
      * Layer type.

src/Mapper/Layer/MarkersLayerMapper.php

@@ -20,6 +20,7 @@ use Netzmacht\Contao\Leaflet\Frontend\RequestUrl;
 use Netzmacht\Contao\Leaflet\Request\Request;
 use Netzmacht\JavascriptBuilder\Type\Expression;
 use Netzmacht\LeafletPHP\Definition;
+use Netzmacht\LeafletPHP\Plugins\Omnivore\GeoJson as OmnivoreGeoJson;
 use Netzmacht\LeafletPHP\Value\GeoJson\FeatureCollection;
 use Netzmacht\LeafletPHP\Definition\Group\GeoJson;
 
@@ -43,10 +44,10 @@ class MarkersLayerMapper extends AbstractLayerMapper implements GeoJsonMapper
     protected function getClassName(Model $model, DefinitionMapper $mapper, Request $request = null)
     {
         if ($model->deferred) {
-            return 'Netzmacht\LeafletPHP\Plugins\Omnivore\GeoJson';
+            return OmnivoreGeoJson::class;
         }
 
-        return 'Netzmacht\LeafletPHP\Definition\Group\GeoJson';
+        return GeoJson::class;
     }
 
     /**

src/Mapper/Layer/ProviderLayerMapper.php

@@ -17,6 +17,7 @@ use Netzmacht\Contao\Leaflet\Mapper\DefinitionMapper;
 use Netzmacht\Contao\Leaflet\Mapper\OptionsBuilder;
 use Netzmacht\Contao\Leaflet\Request\Request;
 use Netzmacht\LeafletPHP\Definition;
+use Netzmacht\LeafletPHP\Plugins\LeafletProviders\Provider;
 
 /**
  * Class ProviderLayerMapper maps the layer model to the tile provider definition.
@@ -60,7 +61,7 @@ class ProviderLayerMapper extends AbstractLayerMapper
             return $this->providers[$model->tile_provider]['class'];
         }
 
-        return 'Netzmacht\LeafletPHP\Plugins\LeafletProviders\Provider';
+        return Provider::class;
     }
 
     /**

src/Mapper/Layer/TileLayerMapper.php

@@ -32,7 +32,7 @@ class TileLayerMapper extends AbstractLayerMapper
      *
      * @var string
      */
-    protected static $definitionClass = 'Netzmacht\LeafletPHP\Definition\Raster\TileLayer';
+    protected static $definitionClass = TileLayer::class;
 
     /**
      * The layer type.

src/Mapper/Layer/VectorsLayerMapper.php

@@ -21,6 +21,7 @@ use Netzmacht\Contao\Leaflet\Frontend\RequestUrl;
 use Netzmacht\Contao\Leaflet\Request\Request;
 use Netzmacht\JavascriptBuilder\Type\Expression;
 use Netzmacht\LeafletPHP\Definition;
+use Netzmacht\LeafletPHP\Plugins\Omnivore\GeoJson as OmnivoreGeoJson;
 use Netzmacht\LeafletPHP\Value\GeoJson\FeatureCollection;
 use Netzmacht\LeafletPHP\Definition\Group\GeoJson;
 
@@ -44,10 +45,10 @@ class VectorsLayerMapper extends AbstractLayerMapper implements GeoJsonMapper
     protected function getClassName(Model $model, DefinitionMapper $mapper, Request $request = null)
     {
         if ($model->deferred) {
-            return 'Netzmacht\LeafletPHP\Plugins\Omnivore\GeoJson';
+            return OmnivoreGeoJson::class;
         }
 
-        return 'Netzmacht\LeafletPHP\Definition\Group\GeoJson';
+        return GeoJson::class;
     }
 
     /**