org.apache.beam.fn.harness.ToStringFnRunner Maven / Gradle / Ivy
/*
* 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.fn.harness;
import com.google.auto.service.AutoService;
import java.util.Map;
import java.util.Objects;
import org.apache.beam.model.pipeline.v1.RunnerApi.PTransform;
import org.apache.beam.sdk.function.ThrowingFunction;
import org.apache.beam.sdk.util.construction.PTransformTranslation;
import org.apache.beam.sdk.values.KV;
import org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.collect.ImmutableMap;
/**
* Translates from elements to human-readable string.
*
* Translation function:
*
*
* - Input: {@code KV
}
* - Output: {@code KV
}
*
*
* For each element, the human-readable string is returned. The nonce is used by a runner to
* associate each input with its output. The nonce is represented as an opaque set of bytes.
*/
public class ToStringFnRunner {
static final String URN = PTransformTranslation.TO_STRING_TRANSFORM_URN;
/**
* A registrar which provides a factory to handle translating elements to a human readable string.
*/
@AutoService(PTransformRunnerFactory.Registrar.class)
public static class Registrar implements PTransformRunnerFactory.Registrar {
@Override
@SuppressWarnings({
"rawtypes" // TODO(https://github.com/apache/beam/issues/20447)
})
public Map getPTransformRunnerFactories() {
return ImmutableMap.of(
URN,
MapFnRunners.forValueMapFnFactory(ToStringFnRunner::createToStringFunctionForPTransform));
}
}
static ThrowingFunction, KV> createToStringFunctionForPTransform(
String ptransformId, PTransform pTransform) {
return (KV input) -> KV.of(input.getKey(), Objects.toString(input.getValue()));
}
}