added getCollectionNames method

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoOperations.java

@@ -54,6 +54,8 @@ public interface MongoOperations {
 	void createCollection(String collectionName,
 			CollectionOptions collectionOptions);
 
+	List<String> getCollectionNames();
+	
 	DBCollection getCollection(String collectionName);
 
 	boolean collectionExists(String collectionName);

spring-data-mongodb/src/main/java/org/springframework/data/document/mongodb/MongoTemplate.java

@@ -469,6 +469,13 @@ public class MongoTemplate implements InitializingBean, MongoOperations {
 		return results;
 	}
 
+	/* (non-Javadoc)
+	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollectionNames()
+	 */
+	public List<String> getCollectionNames() {
+		return new ArrayList<String>(getDb().getCollectionNames());
+	}
+
 	/* (non-Javadoc)
 	 * @see org.springframework.data.document.mongodb.MongoOperations#getCollection(java.lang.String, java.lang.Class, org.springframework.data.document.mongodb.MongoReader)
 	 */