yaooqinn commented on a change in pull request #32515: URL: https://github.com/apache/spark/pull/32515#discussion_r631194854
########## File path: sql/core/src/main/scala/org/apache/spark/sql/SparkSessionExtensionsProvider.scala ########## @@ -0,0 +1,82 @@ +/* + * 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.spark.sql + +import org.apache.spark.annotation.{DeveloperApi, Experimental, Unstable} + +// scalastyle:off line.size.limit +/** + * :: Experimental :: + * + * Base trait for implementations used by [[SparkSessionExtensions]] + * + * + * For example, now we have an external function named `Age` to register as an extension for SparkSession: + * + * + * {{{ + * package org.apache.spark.examples.extensions + * + * import org.apache.spark.sql.catalyst.expressions.{CurrentDate, Expression, RuntimeReplaceable, SubtractDates} + * + * case class Age(birthday: Expression, child: Expression) extends RuntimeReplaceable { + * + * def this(birthday: Expression) = this(birthday, SubtractDates(CurrentDate(), birthday)) + * override def exprsReplaced: Seq[Expression] = Seq(birthday) + * override protected def withNewChildInternal(newChild: Expression): Expression = copy(newChild) + * } + * }}} + * + * We need to create our extension which inherits [[SparkSessionExtensionsProvider]] + * Example: + * + * {{{ + * package org.apache.spark.examples.extensions + * + * import org.apache.spark.sql.{SparkSessionExtensions, SparkSessionExtensionsProvider} + * import org.apache.spark.sql.catalyst.FunctionIdentifier + * import org.apache.spark.sql.catalyst.expressions.{Expression, ExpressionInfo} + * + * class MyExtensions extends SparkSessionExtensionsProvider { + * override def apply(v1: SparkSessionExtensions): Unit = { + * v1.injectFunction( + * (new FunctionIdentifier("age"), + * new ExpressionInfo(classOf[Age].getName, + * "age"), (children: Seq[Expression]) => new Age(children.head))) + * } + * } + * }}} + * + * We can inject `MyExtensions` in three ways, + * + * <ul> + * <li>[[SparkSession.Builder.withExtensions]]</li> + * <li>Config - spark.sql.extensions</li> + * <li>[[java.util.ServiceLoader]] - Add to src/main/resources/META-INF/services/org.apache.spark.sql.SparkSessionExtensionsProvider</li> + * </ul> + * + * @since 3.2.0 + * + * @note We make NO guarantee about the stability regarding binary compatibility and source compatibility of methods here. + * It's experimental and intended for developers Review comment: nice suggession -- 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 --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
