liyuheng55555 commented on code in PR #9236: URL: https://github.com/apache/iotdb/pull/9236#discussion_r1129163281
########## server/src/main/java/org/apache/iotdb/db/mpp/plan/expression/visitor/CollectVisitor.java: ########## @@ -0,0 +1,62 @@ +/* + * 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.iotdb.db.mpp.plan.expression.visitor; + +import org.apache.iotdb.db.mpp.plan.expression.Expression; +import org.apache.iotdb.db.mpp.plan.expression.binary.BinaryExpression; +import org.apache.iotdb.db.mpp.plan.expression.leaf.LeafOperand; +import org.apache.iotdb.db.mpp.plan.expression.ternary.TernaryExpression; +import org.apache.iotdb.db.mpp.plan.expression.unary.UnaryExpression; + +import java.util.ArrayList; +import java.util.List; + +/** + * Simply collects result from child-expression. For example, two child give me 3 and 4 results, I + * will return 3+4 = 7 results to upper level. + */ +public class CollectVisitor extends ExpressionAnalyzeVisitor<List<Expression>, Void> { + protected List<Expression> collectFromChild(Expression expression) { + List<Expression> result = new ArrayList<>(); + for (Expression child : expression.getExpressions()) result.addAll(process(child, null)); + return result; + } + + @Override + public List<Expression> visitTernaryExpression( + TernaryExpression ternaryExpression, Void context) { + return collectFromChild(ternaryExpression); + } + + @Override + public List<Expression> visitBinaryExpression(BinaryExpression binaryExpression, Void context) { + return collectFromChild(binaryExpression); + } + + @Override + public List<Expression> visitUnaryExpression(UnaryExpression unaryExpression, Void context) { + return collectFromChild(unaryExpression); + } + + @Override + public List<Expression> visitLeafOperand(LeafOperand leafOperand, Void context) { + return super.visitLeafOperand(leafOperand, context); + } Review Comment: done. -- 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]
