amaliujia commented on a change in pull request #13305: URL: https://github.com/apache/beam/pull/13305#discussion_r543909278
########## File path: sdks/java/extensions/sql/udf/src/main/java/org/apache/beam/sdk/extensions/sql/udf/ScalarFn.java ########## @@ -0,0 +1,50 @@ +/* + * 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.beam.sdk.extensions.sql.udf; + +import java.io.Serializable; +import java.lang.annotation.ElementType; +import java.lang.annotation.Retention; +import java.lang.annotation.RetentionPolicy; +import java.lang.annotation.Target; + +/** + * A scalar function that can be executed as part of a SQL query. Subclasses must contain exactly + * one method annotated with {@link ApplyMethod}, which will be applied to the SQL function + * arguments at runtime. + * + * <p>For example: + * + * <pre><code> + * public class IncrementFn extends ScalarFn { + * {@literal @ApplyMethod} + * public Long increment(Long i) { + * return i + 1; + * } + * } + * </code></pre> + */ +public abstract class ScalarFn implements Serializable { + /** + * Annotates the single method in a {@link ScalarFn} implementation that is to be applied to SQL + * function arguments. + */ + @Retention(RetentionPolicy.RUNTIME) + @Target(ElementType.METHOD) + public static @interface ApplyMethod {} Review comment: Should be marked as @Experimental? ---------------------------------------------------------------- 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]
