amaliujia commented on a change in pull request #13593: URL: https://github.com/apache/beam/pull/13593#discussion_r547086805
########## File path: sdks/java/extensions/sql/zetasql/src/main/java/org/apache/beam/sdk/extensions/sql/zetasql/translation/impl/ScalarFnImpl.java ########## @@ -0,0 +1,78 @@ +/* + * 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.zetasql.translation.impl; + +import java.lang.reflect.Method; +import java.lang.reflect.Modifier; +import java.util.Arrays; +import java.util.Collection; +import org.apache.beam.sdk.extensions.sql.udf.ScalarFn; +import org.apache.beam.sdk.util.common.ReflectHelpers; + +/** Implementation logic for {@link ScalarFn}. */ +public class ScalarFnImpl { + /** + * Gets the method annotated with {@link + * org.apache.beam.sdk.extensions.sql.udf.ScalarFn.ApplyMethod} from {@code scalarFn}. + * + * <p>There must be exactly one method annotated with {@link + * org.apache.beam.sdk.extensions.sql.udf.ScalarFn.ApplyMethod}, and it must be public and + * non-static. + */ + public static Method getApplyMethod(ScalarFn scalarFn) { + Class<? extends ScalarFn> clazz = scalarFn.getClass(); + Collection<Method> matches = + ReflectHelpers.declaredMethodsWithAnnotation( + ScalarFn.ApplyMethod.class, clazz, ScalarFn.class); + + if (matches.isEmpty()) { + throw new IllegalArgumentException( + String.format( + "No method annotated with @%s found in class %s.", + ScalarFn.ApplyMethod.class.getSimpleName(), clazz.getName())); + } + + // If we have at least one match, then either it should be the only match + // or it should be an extension of the other matches (which came from parent + // classes). + Method first = matches.iterator().next(); + for (Method other : matches) { Review comment: What will happen if we choose one to execute (can print which is chosen and other methods into log)? ########## File path: sdks/java/extensions/sql/zetasql/src/main/java/org/apache/beam/sdk/extensions/sql/zetasql/translation/impl/ScalarFnImpl.java ########## @@ -0,0 +1,78 @@ +/* + * 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.zetasql.translation.impl; + +import java.lang.reflect.Method; +import java.lang.reflect.Modifier; +import java.util.Arrays; +import java.util.Collection; +import org.apache.beam.sdk.extensions.sql.udf.ScalarFn; +import org.apache.beam.sdk.util.common.ReflectHelpers; + +/** Implementation logic for {@link ScalarFn}. */ +public class ScalarFnImpl { + /** + * Gets the method annotated with {@link + * org.apache.beam.sdk.extensions.sql.udf.ScalarFn.ApplyMethod} from {@code scalarFn}. + * + * <p>There must be exactly one method annotated with {@link + * org.apache.beam.sdk.extensions.sql.udf.ScalarFn.ApplyMethod}, and it must be public and + * non-static. + */ + public static Method getApplyMethod(ScalarFn scalarFn) { + Class<? extends ScalarFn> clazz = scalarFn.getClass(); + Collection<Method> matches = + ReflectHelpers.declaredMethodsWithAnnotation( + ScalarFn.ApplyMethod.class, clazz, ScalarFn.class); + + if (matches.isEmpty()) { + throw new IllegalArgumentException( + String.format( + "No method annotated with @%s found in class %s.", + ScalarFn.ApplyMethod.class.getSimpleName(), clazz.getName())); + } + + // If we have at least one match, then either it should be the only match + // or it should be an extension of the other matches (which came from parent + // classes). + Method first = matches.iterator().next(); + for (Method other : matches) { + if (!first.getName().equals(other.getName()) + || !Arrays.equals(first.getParameterTypes(), other.getParameterTypes())) { + throw new IllegalArgumentException( + String.format( + "Found multiple methods annotated with @%s. [%s] and [%s]", + ScalarFn.ApplyMethod.class.getSimpleName(), + ReflectHelpers.formatMethod(first), + ReflectHelpers.formatMethod(other))); + } + } + + // Method must be public and non-static. Review comment: Make sense it have to be public, but why cannot be static? (because of it overwrites the interface function which is not static)? ---------------------------------------------------------------- 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]
