Fix Spark 3.1.0 shim build error in GpuHashJoin

shims/spark310/src/main/scala/com/nvidia/spark/rapids/shims/spark310/GpuHashJoin.scala

@@ -19,13 +19,10 @@ import ai.rapids.cudf.{NvtxColor, Table}
 import com.nvidia.spark.rapids._
 
 import org.apache.spark.TaskContext
-import org.apache.spark.rdd.RDD
-import org.apache.spark.sql.catalyst.InternalRow
 import org.apache.spark.sql.catalyst.expressions.{Attribute, Expression}
-import org.apache.spark.sql.catalyst.expressions.codegen.CodegenContext
 import org.apache.spark.sql.catalyst.optimizer.{BuildLeft, BuildRight}
 import org.apache.spark.sql.catalyst.plans.{ExistenceJoin, FullOuter, InnerLike, JoinType, LeftAnti, LeftExistence, LeftOuter, LeftSemi, RightOuter}
-import org.apache.spark.sql.execution.joins.HashJoin
+import org.apache.spark.sql.execution.joins.HashJoinWithoutCodegen
 import org.apache.spark.sql.execution.metric.SQLMetric
 import org.apache.spark.sql.vectorized.{ColumnarBatch, ColumnVector}
 
@@ -45,9 +42,7 @@ object GpuHashJoin {
   }
 }
 
-trait GpuHashJoin extends GpuExec with HashJoin {
-
-  override def supportCodegen: Boolean = false
+trait GpuHashJoin extends GpuExec with HashJoinWithoutCodegen {
 
   override def output: Seq[Attribute] = {
     joinType match {
@@ -247,13 +242,4 @@ trait GpuHashJoin extends GpuExec with HashJoin {
       joinedTable.close()
     }
   }
-
-  override def inputRDDs(): Seq[RDD[InternalRow]] = {
-    throw new UnsupportedOperationException("inputRDDs is used by codegen which we don't support")
-  }
-
-  protected override def prepareRelation(ctx: CodegenContext): (String, Boolean) = {
-    throw new UnsupportedOperationException(
-      "prepareRelation is used by codegen which we don't support")
-  }
 }

shims/spark310/src/main/scala/org/apache/spark/sql/execution/joins/HashJoinWithoutCodegen.scala

@@ -0,0 +1,39 @@
+/*
+ * Copyright (c) 2020, NVIDIA CORPORATION.
+ *
+ * Licensed 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.joins
+
+import org.apache.spark.rdd.RDD
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.codegen.CodegenContext
+
+/**
+ * This trait is used to implement a hash join that does not support codegen.
+ * It is in the org.apache.spark.sql.execution.joins package to access the
+ * `HashedRelationInfo` class which is private to that package but needed by
+ * any class implementing `HashJoin`.
+ */
+trait HashJoinWithoutCodegen extends HashJoin {
+  override def supportCodegen: Boolean = false
+
+  override def inputRDDs(): Seq[RDD[InternalRow]] = {
+    throw new UnsupportedOperationException("inputRDDs is used by codegen which we don't support")
+  }
+
+  protected override def prepareRelation(ctx: CodegenContext): HashedRelationInfo = {
+    throw new UnsupportedOperationException(
+      "prepareRelation is used by codegen which is not supported for this join")
+  }
+}