twalthr commented on a change in pull request #8062: [FLINK-11884][table] Implement expression resolution on top of new Expressions URL: https://github.com/apache/flink/pull/8062#discussion_r273070489
########## File path: flink-table/flink-table-planner/src/main/java/org/apache/flink/table/expressions/rules/OverWindowResolverRule.java ########## @@ -0,0 +1,105 @@ +/* + * 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.flink.table.expressions.rules; + +import org.apache.flink.annotation.Internal; +import org.apache.flink.table.api.ValidationException; +import org.apache.flink.table.expressions.ApiExpressionDefaultVisitor; +import org.apache.flink.table.expressions.BuiltInFunctionDefinitions; +import org.apache.flink.table.expressions.CallExpression; +import org.apache.flink.table.expressions.CurrentRange; +import org.apache.flink.table.expressions.CurrentRow; +import org.apache.flink.table.expressions.Expression; +import org.apache.flink.table.expressions.PlannerExpression; +import org.apache.flink.table.plan.logical.LogicalOverWindow; +import org.apache.flink.table.typeutils.RowIntervalTypeInfo; + +import java.util.ArrayList; +import java.util.List; +import java.util.stream.Collectors; + +import static java.util.Arrays.asList; +import static java.util.stream.Collectors.toList; + +/** + * Joins call to {@link BuiltInFunctionDefinitions#OVER} with corresponding over window + * and creates a fully resolved over aggregation. + */ +@Internal +final class OverWindowResolverRule implements ResolverRule { + + @Override + public List<Expression> apply(List<Expression> expression, ResolutionContext context) { + return expression.stream() + .map(expr -> expr.accept(new ExpressionResolverVisitor(context))) + .collect(Collectors.toList()); + } + + private class ExpressionResolverVisitor extends ApiExpressionDefaultVisitor<Expression> { + + private final ResolutionContext context; + + ExpressionResolverVisitor(ResolutionContext context) { + this.context = context; + } + + @Override + public Expression visitCall(CallExpression call) { + + if (call.getFunctionDefinition() == BuiltInFunctionDefinitions.OVER) { + List<Expression> children = call.getChildren(); + Expression alias = children.get(1); + + LogicalOverWindow referenceWindow = context.getOverWindow(alias) + .orElseThrow(() -> new ValidationException("Could not resolve over call.")); + + Expression following = calculateOverWindowFollowing(referenceWindow); + List<Expression> newArgs = new ArrayList<>(asList( + children.get(0), + referenceWindow.orderBy(), + referenceWindow.preceding(), + following)); + + newArgs.addAll(referenceWindow.partitionBy()); + return new CallExpression(call.getFunctionDefinition(), newArgs); + } else { + return new CallExpression( + call.getFunctionDefinition(), + call.getChildren().stream().map(expr -> expr.accept(this)).collect(toList())); + } + } + + private Expression calculateOverWindowFollowing(LogicalOverWindow referenceWindow) { + return referenceWindow.following().orElseGet(() -> { + PlannerExpression preceding = context.bridge(referenceWindow.preceding()); + if (preceding.resultType() instanceof RowIntervalTypeInfo) { + return new CurrentRow(); Review comment: Change to a call instead of planner expressions. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
