1 files changed, 40 insertions, 0 deletions
diff --git a/dsa/FireBase/Query/IFirebaseQuery.cs b/dsa/FireBase/Query/IFirebaseQuery.cs
new file mode 100644
index 0000000..0da4b15
--- /dev/null
+++ b/dsa/FireBase/Query/IFirebaseQuery.cs
@@ -0,0 +1,40 @@
+using System;
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using Firebase.Database.Streaming;
+
+namespace Firebase.Database.Query
+{
+    /// <summary>
+    ///     The FirebaseQuery interface.
+    /// </summary>
+    public interface IFirebaseQuery
+    {
+        /// <summary>
+        ///     Gets the owning client of this query.
+        /// </summary>
+        FirebaseClient Client { get; }
+
+        /// <summary>
+        ///     Retrieves items which exist on the location specified by this query instance.
+        /// </summary>
+        /// <param name="timeout"> Optional timeout value. </param>
+        /// <typeparam name="T"> Type of the items. </typeparam>
+        /// <returns> Collection of <see cref="FirebaseObject{T}" />. </returns>
+        Task<IReadOnlyCollection<FirebaseObject<T>>> OnceAsync<T>(TimeSpan? timeout = null);
+
+        /// <summary>
+        ///     Returns current location as an observable which allows to real-time listening to events from the firebase server.
+        /// </summary>
+        /// <typeparam name="T"> Type of the items. </typeparam>
+        /// <returns> Cold observable of <see cref="FirebaseEvent{T}" />. </returns>
+        IObservable<FirebaseEvent<T>> AsObservable<T>(
+            EventHandler<ExceptionEventArgs<FirebaseException>> exceptionHandler, string elementRoot = "");
+
+        /// <summary>
+        ///     Builds the actual url of this query.
+        /// </summary>
+        /// <returns> The <see cref="string" />. </returns>
+        Task<string> BuildUrlAsync();
+    }
+}
+\ No newline at end of file