924060929 commented on code in PR #10947: URL: https://github.com/apache/doris/pull/10947#discussion_r926227078
########## fe/fe-core/src/main/java/org/apache/doris/nereids/trees/expressions/CaseWhen.java: ########## @@ -0,0 +1,129 @@ +// 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.doris.nereids.trees.expressions; + +import org.apache.doris.nereids.exceptions.UnboundException; +import org.apache.doris.nereids.trees.expressions.visitor.ExpressionVisitor; +import org.apache.doris.nereids.types.DataType; + +import com.google.common.base.Preconditions; +import com.google.common.collect.ImmutableList; + +import java.util.ArrayList; +import java.util.List; +import java.util.Optional; +import java.util.stream.Collectors; + +/** + * The internal representation of + * CASE [expr] WHEN expr THEN expr [WHEN expr THEN expr ...] [ELSE expr] END + * Each When/Then is stored as two consecutive children (whenExpr, thenExpr). + * If a case expr is given, convert it to equalTo(caseExpr, whenExpr) and set it to whenExpr. + * If an else expr is given then it is the last child. + */ +public class CaseWhen extends Expression { + /** + * If default value exists, then defaultValueIndex is the index of the last element in children, + * otherwise it is -1 + */ + private final int defaultValueIndex; Review Comment: utilize index to get different part of children is ugly, we should refactor to remove children from AbstractTreeNode and provide children by concrete child class later -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
