| /* |
| * 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.runners.core.construction; |
| |
| import com.google.auto.service.AutoService; |
| import java.util.Iterator; |
| import java.util.ServiceLoader; |
| import java.util.function.Predicate; |
| import org.apache.beam.model.pipeline.v1.RunnerApi; |
| |
| /** |
| * An extension point for users to define their own native transforms for usage with specific |
| * runners. This extension point enables shared libraries within the Apache Beam codebase to treat |
| * the native transform as a primitive transforms that the runner implicitly understands. |
| * |
| * <p><b>Warning:</b>Usage of native transforms within pipelines will prevent users from migrating |
| * between runners as there is no expectation that the transform will be understood by all runners. |
| * Note that for some use cases this can be a way to test out a new type of transform on a limited |
| * set of runners and promote its adoption as a primitive within the Apache Beam model. |
| * |
| * <p>Note that users are required to ensure that translation and execution for the native transform |
| * is supported by their runner. |
| * |
| * <p>Automatic registration occurs by creating a {@link ServiceLoader} entry and a concrete |
| * implementation of the {@link IsNativeTransform} interface. It is optional but recommended to use |
| * one of the many build time tools such as {@link AutoService} to generate the necessary META-INF |
| * files automatically. |
| */ |
| public class NativeTransforms { |
| /** |
| * Returns true if an only if the Runner understands this transform and can handle it directly. |
| */ |
| public static boolean isNative(RunnerApi.PTransform pTransform) { |
| // TODO(BEAM-10109) Use default (context) classloader. |
| Iterator<IsNativeTransform> matchers = |
| ServiceLoader.load(IsNativeTransform.class, NativeTransforms.class.getClassLoader()) |
| .iterator(); |
| while (matchers.hasNext()) { |
| if (matchers.next().test(pTransform)) { |
| return true; |
| } |
| } |
| return false; |
| } |
| |
| /** A predicate which returns true if and only if the transform is a native transform. */ |
| public interface IsNativeTransform extends Predicate<RunnerApi.PTransform> { |
| @Override |
| boolean test(RunnerApi.PTransform pTransform); |
| } |
| } |