singhpk234 commented on code in PR #1287: URL: https://github.com/apache/polaris/pull/1287#discussion_r2053037617
########## extension/persistence/relational-jdbc/src/main/java/org/apache/polaris/extension/persistence/relational/jdbc/ResultSetToObjectConverter.java: ########## @@ -0,0 +1,107 @@ +/* + * 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.polaris.extension.persistence.relational.jdbc; + +import jakarta.annotation.Nonnull; +import java.lang.reflect.Field; +import java.sql.ResultSet; +import java.sql.ResultSetMetaData; +import java.sql.SQLException; +import java.util.ArrayList; +import java.util.List; +import java.util.Locale; +import java.util.function.Function; +import java.util.function.Predicate; + +public class ResultSetToObjectConverter { + + public static <T, R> List<R> collect( + @Nonnull ResultSet resultSet, + @Nonnull Class<T> targetClass, + @Nonnull Function<T, R> transformer, + Predicate<R> entityFilter, + int limit) + throws ReflectiveOperationException, SQLException { + List<R> resultList = new ArrayList<>(); + ResultSetMetaData metaData = resultSet.getMetaData(); + int columnCount = metaData.getColumnCount(); + String[] columnNames = new String[columnCount + 1]; // 1-based indexing + + for (int i = 1; i <= columnCount; i++) { + columnNames[i] = + metaData + .getColumnLabel(i) + .toLowerCase(Locale.ROOT); // or getColumnName(), lowercase to match field names + } + + while (resultSet.next() && resultList.size() < limit) { + T object = targetClass.getDeclaredConstructor().newInstance(); // Create a new instance + for (int i = 1; i <= columnCount; i++) { + String columnName = columnNames[i]; + Object value; + // TODO: This handling doesn't works for H2, works fine with Postgres. + // if (columnName.contains("properties")) { + // value = resultSet.getString(i); + // } else { + // value = resultSet.getObject(i); + // } + value = resultSet.getObject(i); + + try { + Field field = targetClass.getDeclaredField(columnName); + field.setAccessible(true); // Allow access to private fields + field.set(object, value); + } catch (NoSuchFieldException e) { + // Handle case where column name doesn't match field name (e.g., snake_case vs. camelCase) + // You could implement more sophisticated matching logic here, or use annotations. + try { + Field field = targetClass.getDeclaredField(convertSnakeCaseToCamelCase(columnName)); + field.setAccessible(true); + field.set(object, value); + } catch (NoSuchFieldException e2) { + // if still not found, just skip it. + } + } + } + R entity = transformer.apply(object); + if (entityFilter == null || entityFilter.test(entity)) { + resultList.add(entity); + } + } + return resultList; + } + + private static String convertSnakeCaseToCamelCase(String snakeCase) { Review Comment: I though the name is sufficient that it takes a snakeCase string and covert to Camel Case, this is a private function as well, I honestly don't understand whats un:readable here ? -- 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: issues-unsubscr...@polaris.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
