Include possibility to specify custom marshaller

src/main/groovy/grails/plugins/elasticsearch/conversion/JSONDomainFactory.groovy

@@ -55,55 +55,57 @@ class JSONDomainFactory {
         if (object == null) {
             return null
         }
-        def marshaller
+        def marshaller = null
         def objectClass = object.getClass()
 
+        // Check if we arrived from searchable domain class.
+        def parentObject = marshallingContext.peekDomainObject()
+        GrailsDomainClass domainClass = getDomainClass(parentObject)
+        def propertyMapping = elasticSearchContextHolder.getMappingContext(domainClass)?.getPropertyMapping(marshallingContext.lastParentPropertyName)
+        def customMarshaller = propertyMapping?.customMarshaller
+
+        if (customMarshaller && customMarshaller instanceof Class) {
+            marshaller = customMarshaller.newInstance()
+        }
+
         // Resolve collections.
         // Check for direct marshaller matching
-        if (object instanceof Collection) {
+        if (!marshaller && object instanceof Collection) {
             marshaller = new CollectionMarshaller()
         }
 
         if (!marshaller && DEFAULT_MARSHALLERS[objectClass]) {
             marshaller = DEFAULT_MARSHALLERS[objectClass].newInstance()
         }
 
-        if (!marshaller) {
-
-            // Check if we arrived from searchable domain class.
-            def parentObject = marshallingContext.peekDomainObject()
-            if (parentObject && marshallingContext.lastParentPropertyName && DomainClassArtefactHandler.isDomainClass(parentObject.getClass())) {
-                GrailsDomainClass domainClass = getDomainClass(parentObject)
-                def propertyMapping = elasticSearchContextHolder.getMappingContext(domainClass)?.getPropertyMapping(marshallingContext.lastParentPropertyName)
-                def converter = propertyMapping?.converter
-                // Property has converter information. Lets see how we can apply it.
-                if (converter) {
-                    // Property editor?
-                    if (converter instanceof Class) {
-                        if (PropertyEditor.isAssignableFrom(converter)) {
-                            marshaller = new PropertyEditorMarshaller(propertyEditorClass: converter)
-                        }
-                    }
-                } else if (propertyMapping?.isDynamic()) {
-                    marshaller = new DynamicValueMarshaller()
-                } else if (propertyMapping?.reference) {
-                    def refClass = propertyMapping.getBestGuessReferenceType()
-                    marshaller = new SearchableReferenceMarshaller(refClass: refClass)
-                } else if (propertyMapping?.component) {
-                    if (propertyMapping?.isGeoPoint()) {
-                        marshaller = new GeoPointMarshaller()
-                    } else {
-                        marshaller = new DeepDomainClassMarshaller()
+        if (!marshaller && parentObject && marshallingContext.lastParentPropertyName && DomainClassArtefactHandler.isDomainClass(parentObject.getClass())) {
+            def converter = propertyMapping?.converter
+            // Property has converter information. Lets see how we can apply it.
+            if (converter) {
+                // Property editor?
+                if (converter instanceof Class) {
+                    if (PropertyEditor.isAssignableFrom(converter)) {
+                        marshaller = new PropertyEditorMarshaller(propertyEditorClass: converter)
                     }
                 }
+            } else if (propertyMapping?.isDynamic()) {
+                marshaller = new DynamicValueMarshaller()
+            } else if (propertyMapping?.reference) {
+                def refClass = propertyMapping.getBestGuessReferenceType()
+                marshaller = new SearchableReferenceMarshaller(refClass: refClass)
+            } else if (propertyMapping?.component) {
+                if (propertyMapping?.isGeoPoint()) {
+                    marshaller = new GeoPointMarshaller()
+                } else {
+                    marshaller = new DeepDomainClassMarshaller()
+                }
             }
         }
 
         if (!marshaller) {
-            // TODO : support user custom marshaller/converter (& marshaller registration)
             // Check for domain classes
             if (DomainClassArtefactHandler.isDomainClass(objectClass)) {
-                def propertyMapping = elasticSearchContextHolder.getMappingContext(getDomainClass(marshallingContext.peekDomainObject()))?.getPropertyMapping(marshallingContext.lastParentPropertyName)
+                propertyMapping = elasticSearchContextHolder.getMappingContext(getDomainClass(marshallingContext.peekDomainObject()))?.getPropertyMapping(marshallingContext.lastParentPropertyName)
 
                 if (propertyMapping?.isGeoPoint()) {
                     marshaller = new GeoPointMarshaller()

src/main/groovy/grails/plugins/elasticsearch/mapping/SearchableClassPropertyMapping.groovy

@@ -26,7 +26,7 @@ class SearchableClassPropertyMapping {
     private static final Set<String> SEARCHABLE_MAPPING_OPTIONS = ['boost', 'index', 'analyzer']
     private static final Set<String> SEARCHABLE_SPECIAL_MAPPING_OPTIONS =
             ['component', 'converter', 'reference', 'excludeFromAll', 'maxDepth', 'multi_field', 'parent', 'geoPoint',
-             'alias', 'dynamic', 'attachment']
+             'alias', 'dynamic', 'attachment', 'customMarshaller'] as Set<String>
 
     /** Grails attributes of this property */
     private GrailsDomainClassProperty grailsProperty
@@ -79,6 +79,10 @@ class SearchableClassPropertyMapping {
         specialMappingAttributes.converter
     }
 
+    Object getCustomMarshaller() {
+        specialMappingAttributes.customMarshaller
+    }
+
     Object getReference() {
         specialMappingAttributes.reference
     }