codope commented on a change in pull request #2915: URL: https://github.com/apache/hudi/pull/2915#discussion_r650815907
########## File path: hudi-utilities/src/main/java/org/apache/hudi/utilities/SqlQueryBuilder.java ########## @@ -0,0 +1,160 @@ +/* + * 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.hudi.utilities; + +import org.apache.hudi.common.util.StringUtils; + +/** + * Fluent SQL query builder. + * Current support for: SELECT, FROM, JOIN, ON, WHERE, ORDER BY, LIMIT clauses. + */ +public class SqlQueryBuilder { + + private StringBuilder sqlBuilder; + + private SqlQueryBuilder(StringBuilder sqlBuilder) { + this.sqlBuilder = sqlBuilder; + } + + /** + * Creates a SELECT query. + * + * @param columns The column names to select. + * @return The new {@link SqlQueryBuilder} instance. + */ + public static SqlQueryBuilder select(String... columns) { + if (columns == null || columns.length == 0) { + throw new IllegalArgumentException(); + } + + StringBuilder sqlBuilder = new StringBuilder(); + sqlBuilder.append("select "); + sqlBuilder.append(String.join(", ", columns)); + + return new SqlQueryBuilder(sqlBuilder); + } + + /** + * Appends a FROM clause to a query. + * + * @param tables The table names to select from. + * @return The {@link SqlQueryBuilder} instance. + */ + public SqlQueryBuilder from(String... tables) { + if (tables == null || tables.length == 0) { + throw new IllegalArgumentException(); + } + + sqlBuilder.append(" from "); + sqlBuilder.append(String.join(", ", tables)); Review comment: Added a subtask to take it up after we land this PR. -- 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: [email protected]
