Support Trigger in DataStreamWriter (#153)

src/csharp/Microsoft.Spark.E2ETest/IpcTests/Sql/Streaming/TriggerTests.cs

@@ -0,0 +1,36 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Spark.Sql;
+using Microsoft.Spark.Sql.Streaming;
+using Xunit;
+
+namespace Microsoft.Spark.E2ETest.IpcTests
+{
+    [Collection("Spark E2E Tests")]
+    public class TriggerTests
+    {
+        private readonly SparkSession _spark;
+
+        public TriggerTests(SparkFixture fixture)
+        {
+            _spark = fixture.Spark;
+        }
+
+        /// <summary>
+        /// Test Trigger's static functions
+        /// </summary>
+        [Fact]
+        public void TestSignatures()
+        {
+            Assert.IsType<Trigger>(Trigger.Once());
+
+            Assert.IsType<Trigger>(Trigger.Continuous("1 seconds"));
+            Assert.IsType<Trigger>(Trigger.Continuous(1000));
+
+            Assert.IsType<Trigger>(Trigger.ProcessingTime("1 seconds"));
+            Assert.IsType<Trigger>(Trigger.ProcessingTime(1000));
+        }
+    }
+}

src/csharp/Microsoft.Spark/Sql/Streaming/DataStreamWriter.cs

@@ -118,6 +118,31 @@ public DataStreamWriter Options(Dictionary<string, string> options)
             return this;
         }
 
+        /// <summary>
+        /// Sets the trigger for the stream query.
+        /// </summary>
+        /// <param name="trigger">Trigger object</param>
+        /// <returns>This DataStreamReader object</returns>
+        public DataStreamWriter Trigger(Trigger trigger)
+        {
+            _jvmObject.Invoke("trigger", trigger);
+            return this;
+        }
+
+        /// <summary>
+        /// Specifies the name of the <see cref="StreamingQuery"/> 
+        /// that can be started with `start()`.
+        /// This name must be unique among all the currently active queries 
+        /// in the associated SQLContext.
+        /// </summary>
+        /// <param name="queryName">Query name</param>
+        /// <returns>This DataStreamReader object</returns>
+        public DataStreamWriter QueryName(string queryName)
+        {
+            _jvmObject.Invoke("queryName", queryName);
+            return this;
+        }
+
         /// <summary>
         /// Starts the execution of the streaming query.
         /// </summary>

src/csharp/Microsoft.Spark/Sql/Streaming/Trigger.cs

@@ -0,0 +1,91 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+using Microsoft.Spark.Interop;
+using Microsoft.Spark.Interop.Ipc;
+
+namespace Microsoft.Spark.Sql.Streaming
+{
+    /// <summary>
+    /// Policy used to indicate how often results should be produced by a 
+    /// <see cref="StreamingQuery"/>
+    /// </summary>
+    public sealed class Trigger : IJvmObjectReferenceProvider
+    {
+        private static IJvmBridge Jvm { get; } = SparkEnvironment.JvmBridge;
+        private static readonly string s_triggerClassName = 
+            "org.apache.spark.sql.streaming.Trigger";
+
+        private readonly JvmObjectReference _jvmObject;
+
+        internal Trigger(JvmObjectReference jvmObject) => _jvmObject = jvmObject;
+
+        JvmObjectReference IJvmObjectReferenceProvider.Reference => _jvmObject;
+
+        /// <summary>
+        /// A trigger policy that runs a query periodically based on an interval 
+        /// in processing time.
+        /// If `interval` is 0, the query will run as fast as possible.
+        /// </summary>
+        /// <param name="intervalMs">Milliseconds</param>
+        /// <returns>Trigger Object</returns>
+        public static Trigger ProcessingTime(long intervalMs)
+        {
+            return Apply("ProcessingTime", intervalMs);
+        }
+
+        /// <summary>
+        /// A trigger policy that runs a query periodically based on an interval 
+        /// in processing time.
+        /// If `interval` is effectively 0, the query will run as fast as possible.
+        /// </summary>
+        /// <param name="interval">string representation for interval. eg. "10 seconds"</param>
+        /// <returns>Trigger Object</returns>
+        public static Trigger ProcessingTime(string interval)
+        {
+            return Apply("ProcessingTime", interval);
+        }
+
+        /// <summary>
+        /// A trigger that process only one batch of data in a streaming query 
+        /// then terminates the query.
+        /// </summary>
+        /// <returns>Trigger Object</returns>
+        public static Trigger Once()
+        {
+            return Apply("Once");
+        }
+
+        /// <summary>
+        /// A trigger that continuously processes streaming data,
+        /// asynchronously checkpointing at the specified interval.
+        /// </summary>
+        /// <param name="intervalMs">Milliseconds</param>
+        /// <returns>Trigger Object</returns>
+        public static Trigger Continuous(long intervalMs)
+        {
+            return Apply("Continuous", intervalMs);
+        }
+
+        /// <summary>
+        /// A trigger that continuously processes streaming data,
+        /// asynchronously checkpointing at the specified interval.
+        /// </summary>
+        /// <param name="interval">string representation for interval. eg. "10 seconds"</param>
+        /// <returns>Trigger Object</returns>
+        public static Trigger Continuous(string interval)
+        {
+            return Apply("Continuous", interval);
+        }
+
+        private static Trigger Apply(string funcName, params object[] args)
+        {
+            return new Trigger(
+                (JvmObjectReference)Jvm.CallStaticJavaMethod(
+                    s_triggerClassName,
+                    funcName,
+                    args));
+        }
+    }
+}