Add LimitNode and UnionNode

sql/core/src/main/scala/org/apache/spark/sql/execution/local/LimitNode.scala

@@ -0,0 +1,51 @@
+/*
+* 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.local
+
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.Attribute
+
+
+case class LimitNode(limit: Int, child: LocalNode) extends UnaryLocalNode {
+
+  override def output: Seq[Attribute] = child.output
+
+  override def execute(): OpenCloseRowIterator = new OpenCloseRowIterator {
+
+    private var count = 0
+
+    private val childIter = child.execute()
+
+    override def open(): Unit = childIter.open()
+
+    override def close(): Unit = childIter.close()
+
+    override def getRow: InternalRow = childIter.getRow
+
+    override def advanceNext(): Boolean = {
+      if (count < limit) {
+        count += 1
+        childIter.advanceNext()
+      } else {
+        false
+      }
+    }
+
+  }
+
+}

sql/core/src/main/scala/org/apache/spark/sql/execution/local/UnionNode.scala

@@ -0,0 +1,75 @@
+/*
+* 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.local
+
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions.Attribute
+
+case class UnionNode(children: Seq[LocalNode]) extends LocalNode {
+
+  override def output: Seq[Attribute] = children.head.output
+
+  override def execute(): OpenCloseRowIterator = new OpenCloseRowIterator {
+
+    private var currentIter: OpenCloseRowIterator = _
+
+    private var nextChildIndex: Int = _
+
+    override def open(): Unit = {
+      currentIter = children.head.execute()
+      currentIter.open()
+      nextChildIndex = 1
+    }
+
+    private def advanceToNextChild(): Boolean = {
+      var found = false
+      var exit = false
+      while (!exit && !found) {
+        if (currentIter != null) {
+          currentIter.close()
+        }
+        if (nextChildIndex >= children.size) {
+          found = false
+          exit = true
+        } else {
+          currentIter = children(nextChildIndex).execute()
+          nextChildIndex += 1
+          currentIter.open()
+          found = currentIter.advanceNext()
+        }
+      }
+      found
+    }
+
+    override def close(): Unit = {
+      if (currentIter != null) {
+        currentIter.close()
+      }
+    }
+
+    override def getRow: InternalRow = currentIter.getRow
+
+    override def advanceNext(): Boolean = {
+      if (currentIter.advanceNext()) {
+        true
+      } else {
+        advanceToNextChild()
+      }
+    }
+  }
+}

sql/core/src/test/scala/org/apache/spark/sql/execution/local/LimitNodeSuite.scala

@@ -0,0 +1,37 @@
+/*
+* 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.local
+
+import org.apache.spark.sql.test.SharedSQLContext
+
+class LimitNodeSuite extends LocalNodeTest with SharedSQLContext {
+
+  test("basic") {
+    checkAnswer(testData,
+      node => LimitNode(10, node),
+      testData.limit(10).collect()
+    )
+  }
+
+  test("empty") {
+    checkAnswer(emptyTestData,
+      node => LimitNode(10, node),
+      emptyTestData.limit(10).collect()
+    )
+  }
+}

sql/core/src/test/scala/org/apache/spark/sql/execution/local/UnionNodeSuite.scala

@@ -0,0 +1,52 @@
+/*
+* 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.local
+
+import org.apache.spark.sql.test.SharedSQLContext
+
+class UnionNodeSuite extends LocalNodeTest with SharedSQLContext {
+
+  test("basic") {
+    checkAnswer2(
+      testData,
+      testData,
+      (node1, node2) => UnionNode(Seq(node1, node2)),
+      testData.unionAll(testData).collect()
+    )
+  }
+
+  test("empty") {
+    checkAnswer2(
+      emptyTestData,
+      emptyTestData,
+      (node1, node2) => UnionNode(Seq(node1, node2)),
+      emptyTestData.unionAll(emptyTestData).collect()
+    )
+  }
+
+  test("complicated union") {
+    val dfs = Seq(testData, emptyTestData, emptyTestData, testData, testData, emptyTestData,
+      emptyTestData, emptyTestData, testData, emptyTestData)
+    doCheckAnswer(
+      dfs,
+      nodes => UnionNode(nodes),
+      dfs.reduce(_.unionAll(_)).collect()
+    )
+  }
+
+}