1 files changed, 119 insertions, 0 deletions
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StatefulAggregate.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StatefulAggregate.scala
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--- /dev/null
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/StatefulAggregate.scala
@@ -0,0 +1,119 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License.  You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.execution.streaming
+
+import org.apache.spark.rdd.RDD
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.errors._
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.expressions.codegen.GenerateUnsafeProjection
+import org.apache.spark.sql.execution
+import org.apache.spark.sql.execution.streaming.state._
+import org.apache.spark.sql.execution.SparkPlan
+
+/** Used to identify the state store for a given operator. */
+case class OperatorStateId(
+    checkpointLocation: String,
+    operatorId: Long,
+    batchId: Long)
+
+/**
+ * An operator that saves or restores state from the [[StateStore]].  The [[OperatorStateId]] should
+ * be filled in by `prepareForExecution` in [[IncrementalExecution]].
+ */
+trait StatefulOperator extends SparkPlan {
+  def stateId: Option[OperatorStateId]
+
+  protected def getStateId: OperatorStateId = attachTree(this) {
+    stateId.getOrElse {
+      throw new IllegalStateException("State location not present for execution")
+    }
+  }
+}
+
+/**
+ * For each input tuple, the key is calculated and the value from the [[StateStore]] is added
+ * to the stream (in addition to the input tuple) if present.
+ */
+case class StateStoreRestore(
+    keyExpressions: Seq[Attribute],
+    stateId: Option[OperatorStateId],
+    child: SparkPlan) extends execution.UnaryNode with StatefulOperator {
+
+  override protected def doExecute(): RDD[InternalRow] = {
+    child.execute().mapPartitionsWithStateStore(
+      getStateId.checkpointLocation,
+      operatorId = getStateId.operatorId,
+      storeVersion = getStateId.batchId,
+      keyExpressions.toStructType,
+      child.output.toStructType,
+      new StateStoreConf(sqlContext.conf),
+      Some(sqlContext.streams.stateStoreCoordinator)) { case (store, iter) =>
+        val getKey = GenerateUnsafeProjection.generate(keyExpressions, child.output)
+        iter.flatMap { row =>
+          val key = getKey(row)
+          val savedState = store.get(key)
+          row +: savedState.toSeq
+        }
+    }
+  }
+  override def output: Seq[Attribute] = child.output
+}
+
+/**
+ * For each input tuple, the key is calculated and the tuple is `put` into the [[StateStore]].
+ */
+case class StateStoreSave(
+    keyExpressions: Seq[Attribute],
+    stateId: Option[OperatorStateId],
+    child: SparkPlan) extends execution.UnaryNode with StatefulOperator {
+
+  override protected def doExecute(): RDD[InternalRow] = {
+    child.execute().mapPartitionsWithStateStore(
+      getStateId.checkpointLocation,
+      operatorId = getStateId.operatorId,
+      storeVersion = getStateId.batchId,
+      keyExpressions.toStructType,
+      child.output.toStructType,
+      new StateStoreConf(sqlContext.conf),
+      Some(sqlContext.streams.stateStoreCoordinator)) { case (store, iter) =>
+        new Iterator[InternalRow] {
+          private[this] val baseIterator = iter
+          private[this] val getKey = GenerateUnsafeProjection.generate(keyExpressions, child.output)
+
+          override def hasNext: Boolean = {
+            if (!baseIterator.hasNext) {
+              store.commit()
+              false
+            } else {
+              true
+            }
+          }
+
+          override def next(): InternalRow = {
+            val row = baseIterator.next().asInstanceOf[UnsafeRow]
+            val key = getKey(row)
+            store.put(key.copy(), row.copy())
+            row
+          }
+        }
+    }
+  }
+
+  override def output: Seq[Attribute] = child.output
+}