Add WindowStart and WindowEnd UDFs

ksql-engine/src/main/java/io/confluent/ksql/analyzer/AggregateAnalyzer.java

@@ -28,9 +28,9 @@
 
 public class AggregateAnalyzer extends DefaultTraversalVisitor<Node, AnalysisContext> {
 
-  private AggregateAnalysis aggregateAnalysis;
-  private Analysis analysis;
-  private FunctionRegistry functionRegistry;
+  private final AggregateAnalysis aggregateAnalysis;
+  private final Analysis analysis;
+  private final FunctionRegistry functionRegistry;
 
   private boolean hasAggregateFunction = false;
 

ksql-engine/src/main/java/io/confluent/ksql/function/udaf/placeholder/PlaceholderTableUdaf.java

@@ -0,0 +1,50 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * 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 io.confluent.ksql.function.udaf.placeholder;
+
+import io.confluent.ksql.function.udaf.TableUdaf;
+
+/**
+ * A no-op {@link TableUdaf} that is used as a placeholder for some later hardcoded computation.
+ */
+public final class PlaceholderTableUdaf implements TableUdaf<Long, Long> {
+
+  public static final PlaceholderTableUdaf INSTANCE = new PlaceholderTableUdaf();
+
+  private PlaceholderTableUdaf(){
+  }
+
+  @Override
+  public Long undo(final Long valueToUndo, final Long aggregateValue) {
+    return null;
+  }
+
+  @Override
+  public Long initialize() {
+    return null;
+  }
+
+  @Override
+  public Long aggregate(final Long value, final Long aggregate) {
+    return null;
+  }
+
+  @Override
+  public Long merge(final Long aggOne, final Long aggTwo) {
+    return null;
+  }
+}

ksql-engine/src/main/java/io/confluent/ksql/function/udaf/window/WindowEndKudaf.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * 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 io.confluent.ksql.function.udaf.window;
+
+import io.confluent.ksql.function.udaf.TableUdaf;
+import io.confluent.ksql.function.udaf.UdafDescription;
+import io.confluent.ksql.function.udaf.UdafFactory;
+import io.confluent.ksql.function.udaf.placeholder.PlaceholderTableUdaf;
+
+/**
+ * A placeholder KUDAF for extracting window end times.
+ *
+ * <p>The KUDAF itself does nothing. It's just a placeholder.
+ *
+ * @see WindowSelectMapper
+ */
+@SuppressWarnings("WeakerAccess") // Invoked via reflection.
+@UdafDescription(name = "WindowEnd", author = "Confluent",
+    description = "Returns the window end time, in milliseconds, for the given record. "
+        + "If the given record is not part of a window the function will return NULL.")
+public final class WindowEndKudaf {
+
+  private WindowEndKudaf() {
+  }
+
+  static String getFunctionName() {
+    return "WindowEnd";
+  }
+
+  @UdafFactory(description = "Extracts the window end time")
+  public static TableUdaf<Long, Long> createWindowEnd() {
+    return PlaceholderTableUdaf.INSTANCE;
+  }
+}

ksql-engine/src/main/java/io/confluent/ksql/function/udaf/window/WindowSelectMapper.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * 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 io.confluent.ksql.function.udaf.window;
+
+import com.google.common.collect.ImmutableMap;
+import io.confluent.ksql.GenericRow;
+import io.confluent.ksql.function.KsqlAggregateFunction;
+import java.util.Map;
+import java.util.function.Function;
+import java.util.stream.Collectors;
+import org.apache.kafka.streams.kstream.ValueMapperWithKey;
+import org.apache.kafka.streams.kstream.Window;
+import org.apache.kafka.streams.kstream.Windowed;
+
+/**
+ * Used to handle the special cased {@link WindowStartKudaf} and {@link WindowEndKudaf}.
+ */
+public final class WindowSelectMapper
+    implements ValueMapperWithKey<Windowed<?>, GenericRow, GenericRow> {
+
+  private static final Map<String, Type> WINDOW_FUNCTION_NAMES = ImmutableMap.of(
+      WindowStartKudaf.getFunctionName().toUpperCase(), Type.StartTime,
+      WindowEndKudaf.getFunctionName().toUpperCase(), Type.EndTime
+  );
+
+  private final Map<Integer, Type> windowSelects;
+
+  public WindowSelectMapper(
+      final Map<Integer, KsqlAggregateFunction> aggFunctionsByIndex) {
+    this.windowSelects = aggFunctionsByIndex.entrySet().stream()
+        .filter(e ->
+            WINDOW_FUNCTION_NAMES.containsKey(e.getValue().getFunctionName().toUpperCase()))
+        .collect(Collectors.toMap(
+            Map.Entry::getKey,
+            e -> WINDOW_FUNCTION_NAMES.get(e.getValue().getFunctionName().toUpperCase())));
+  }
+
+  public boolean hasSelects() {
+    return !windowSelects.isEmpty();
+  }
+
+  @Override
+  public GenericRow apply(final Windowed<?> readOnlyKey, final GenericRow row) {
+    final Window window = readOnlyKey.window();
+
+    windowSelects.forEach((index, type) ->
+        row.getColumns().set(index, type.mapper.apply(window)));
+
+    return row;
+  }
+
+  private enum Type {
+    StartTime(Window::start), EndTime(Window::end);
+
+    private final Function<Window, Object> mapper;
+
+    Type(final Function<Window, Object> mapper) {
+      this.mapper = mapper;
+    }
+  }
+}

ksql-engine/src/main/java/io/confluent/ksql/function/udaf/window/WindowStartKudaf.java

@@ -0,0 +1,48 @@
+/*
+ * Copyright 2018 Confluent Inc.
+ *
+ * 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 io.confluent.ksql.function.udaf.window;
+
+import io.confluent.ksql.function.udaf.TableUdaf;
+import io.confluent.ksql.function.udaf.UdafDescription;
+import io.confluent.ksql.function.udaf.UdafFactory;
+import io.confluent.ksql.function.udaf.placeholder.PlaceholderTableUdaf;
+
+/**
+ * A placeholder KUDAF for extracting window start times.
+ *
+ * <p>The KUDAF itself does nothing. It's just a placeholder.
+ *
+ * @see WindowSelectMapper
+ */
+@SuppressWarnings("WeakerAccess") // Invoked via reflection.
+@UdafDescription(name = "WindowStart", author = "Confluent",
+    description = "Returns the window start time, in milliseconds, for the given record. "
+        + "If the given record is not part of a window the function will return NULL.")
+public final class WindowStartKudaf {
+
+  private WindowStartKudaf() {
+  }
+
+  static String getFunctionName() {
+    return "WindowStart";
+  }
+
+  @UdafFactory(description = "Extracts the window start time")
+  public static TableUdaf<Long, Long> createWindowStart() {
+    return PlaceholderTableUdaf.INSTANCE;
+  }
+}

ksql-engine/src/main/java/io/confluent/ksql/planner/plan/AggregateNode.java

@@ -41,8 +41,8 @@
 import io.confluent.ksql.util.KafkaTopicClient;
 import io.confluent.ksql.util.KsqlConfig;
 import io.confluent.ksql.util.KsqlException;
-import io.confluent.ksql.util.Pair;
 import io.confluent.ksql.util.SchemaUtil;
+import io.confluent.ksql.util.SelectExpression;
 import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
@@ -66,12 +66,9 @@ public class AggregateNode extends PlanNode {
   private final List<Expression> groupByExpressions;
   private final WindowExpression windowExpression;
   private final List<Expression> aggregateFunctionArguments;
-
   private final List<FunctionCall> functionList;
   private final List<Expression> requiredColumnList;
-
   private final List<Expression> finalSelectExpressions;
-
   private final Expression havingExpressions;
 
   @JsonCreator
@@ -139,8 +136,8 @@ public List<Expression> getRequiredColumnList() {
     return requiredColumnList;
   }
 
-  private List<Pair<String, Expression>> getFinalSelectExpressions() {
-    final List<Pair<String, Expression>> finalSelectExpressionList = new ArrayList<>();
+  private List<SelectExpression> getFinalSelectExpressions() {
+    final List<SelectExpression> finalSelectExpressionList = new ArrayList<>();
     if (finalSelectExpressions.size() != schema.fields().size()) {
       throw new RuntimeException(
           "Incompatible aggregate schema, field count must match, "
@@ -150,7 +147,7 @@ private List<Pair<String, Expression>> getFinalSelectExpressions() {
           + schema.fields().size());
     }
     for (int i = 0; i < finalSelectExpressions.size(); i++) {
-      finalSelectExpressionList.add(new Pair<>(
+      finalSelectExpressionList.add(SelectExpression.of(
           schema.fields().get(i).name(),
           finalSelectExpressions.get(i)
       ));
@@ -232,17 +229,13 @@ public SchemaKStream buildStream(
     );
 
     final KudafInitializer initializer = new KudafInitializer(aggValToValColumnMap.size());
+
+    final Map<Integer, KsqlAggregateFunction> aggValToFunctionMap = createAggValToFunctionMap(
+        aggregateArgExpanded, aggregateSchema, initializer, aggValToValColumnMap.size(),
+        functionRegistry, internalSchema);
+
     final SchemaKTable schemaKTable = schemaKGroupedStream.aggregate(
-        initializer,
-        createAggValToFunctionMap(
-            aggregateArgExpanded,
-            aggregateSchema,
-            initializer,
-            aggValToValColumnMap.size(),
-            functionRegistry,
-            internalSchema),
-        aggValToValColumnMap,
-        getWindowExpression(),
+        initializer, aggValToFunctionMap, aggValToValColumnMap, getWindowExpression(),
         aggValueGenericRowSerde);
 
     SchemaKTable result = new SchemaKTable(
@@ -368,7 +361,7 @@ private Schema buildAggregateSchema(
   }
 
   private static class InternalSchema {
-    private final List<Pair<String, Expression>> aggArgExpansionList = new ArrayList<>();
+    private final List<SelectExpression> aggArgExpansionList = new ArrayList<>();
     private final Map<String, Integer> internalNameToIndexMap = new HashMap<>();
     private final Map<String, String> expressionToInternalColumnNameMap = new HashMap<>();
 
@@ -389,14 +382,13 @@ private void collectAggregateArgExpressions(
             final String internalColumnName = INTERNAL_COLUMN_NAME_PREFIX
                 + aggArgExpansionList.size();
             internalNameToIndexMap.put(internalColumnName, aggArgExpansionList.size());
-            aggArgExpansionList.add(new Pair<>(internalColumnName, expression));
-            if (!expressionToInternalColumnNameMap.containsKey(expression.toString())) {
-              expressionToInternalColumnNameMap.put(expression.toString(), internalColumnName);
-            }
+            aggArgExpansionList.add(SelectExpression.of(internalColumnName, expression));
+            expressionToInternalColumnNameMap
+                .putIfAbsent(expression.toString(), internalColumnName);
           });
     }
 
-    List<Expression> getInternalExpressionList(final List<Expression> expressionList) {
+    private List<Expression> getInternalExpressionList(final List<Expression> expressionList) {
       return expressionList.stream()
           .map(argExpression -> argExpression instanceof Literal
                                 ? argExpression
@@ -406,27 +398,31 @@ List<Expression> getInternalExpressionList(final List<Expression> expressionList
           .collect(Collectors.toList());
     }
 
-    List<Pair<String, Expression>> updateFinalSelectExpressions(
-        final List<Pair<String, Expression>> finalSelectExpressions) {
+    private List<SelectExpression> updateFinalSelectExpressions(
+        final List<SelectExpression> finalSelectExpressions
+    ) {
       return finalSelectExpressions.stream()
-          .map(finalSelectExpression ->
-                   expressionToInternalColumnNameMap
-                       .containsKey(finalSelectExpression.getRight().toString())
-                   ? new Pair<>(finalSelectExpression.getLeft(),
-                                (Expression)
-                                    new QualifiedNameReference(
-                                        QualifiedName.of(
-                                            expressionToInternalColumnNameMap
-                                                .get(finalSelectExpression.getRight().toString()))))
-                   : new Pair<>(finalSelectExpression.getLeft(), finalSelectExpression.getRight()))
+          .map(finalSelectExpression -> {
+            final String internal = expressionToInternalColumnNameMap
+                .get(finalSelectExpression.getExpression().toString());
+
+            if (internal == null) {
+              return finalSelectExpression;
+            }
+
+            return SelectExpression.of(
+                finalSelectExpression.getName(),
+                new QualifiedNameReference(QualifiedName.of(internal)));
+
+          })
           .collect(Collectors.toList());
     }
 
     String getInternalColumnForExpression(final Expression expression) {
       return expressionToInternalColumnNameMap.get(expression.toString());
     }
 
-    List<Pair<String, Expression>> getAggArgExpansionList() {
+    List<SelectExpression> getAggArgExpansionList() {
       return aggArgExpansionList;
     }