adds support to count in ravendb

Author: otaviojava

ravendb-driver/src/main/java/org/jnosql/diana/ravendb/document/RavenDBDocumentCollectionManager.java

@@ -16,6 +16,8 @@
 package org.jnosql.diana.ravendb.document;
 
 import net.ravendb.client.documents.DocumentStore;
+import net.ravendb.client.documents.queries.Query;
+import net.ravendb.client.documents.session.IDocumentQuery;
 import net.ravendb.client.documents.session.IDocumentSession;
 import net.ravendb.client.documents.session.IEnumerableQuery;
 import net.ravendb.client.documents.session.IMetadataDictionary;
@@ -120,6 +122,15 @@ public List<DocumentEntity> select(DocumentQuery query) {
 
     }
 
+    @Override
+    public long count(String documentCollection) {
+        Objects.requireNonNull(documentCollection, "documentCollection is required");
+        try (IDocumentSession session = store.openSession()) {
+            IDocumentQuery<HashMap> ravenQuery = session.query(HashMap.class, Query.collection(documentCollection));
+            return ravenQuery.count();
+        }
+    }
+
     @Override
     public void close() {
         store.close();

ravendb-driver/src/test/java/org/jnosql/diana/ravendb/document/RavenDBDocumentCollectionManagerTest.java

@@ -352,6 +352,14 @@ private DocumentEntity createSubdocumentList() {
     }
 
 
+    @Test
+    public void shouldCount() {
+        DocumentEntity entity = getEntity();
+        entityManager.insert(entity);
+        assertTrue(entityManager.count(COLLECTION_NAME) > 0);
+    }
+
+
     private DocumentEntity getEntity() {
         DocumentEntity entity = DocumentEntity.of(COLLECTION_NAME);
         Map<String, Object> map = new HashMap<>();