| /* |
| * 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.learning.katas.commontransforms.withkeys; |
| |
| // beam-playground: |
| // name: WithKeys |
| // description: Task from katas to convert each fruit name into a KV of its first letter and itself. |
| // multifile: false |
| // context_line: 40 |
| // categories: |
| // - Combiners |
| |
| import static org.apache.beam.sdk.values.TypeDescriptors.strings; |
| |
| import org.apache.beam.learning.katas.util.Log; |
| import org.apache.beam.sdk.Pipeline; |
| import org.apache.beam.sdk.options.PipelineOptions; |
| import org.apache.beam.sdk.options.PipelineOptionsFactory; |
| import org.apache.beam.sdk.transforms.Create; |
| import org.apache.beam.sdk.transforms.WithKeys; |
| import org.apache.beam.sdk.values.KV; |
| import org.apache.beam.sdk.values.PCollection; |
| |
| public class Task { |
| |
| public static void main(String[] args) { |
| PipelineOptions options = PipelineOptionsFactory.fromArgs(args).create(); |
| Pipeline pipeline = Pipeline.create(options); |
| |
| PCollection<String> words = |
| pipeline.apply( |
| Create.of("apple", "banana", "cherry", "durian", "guava", "melon")); |
| |
| PCollection<KV<String, String>> output = applyTransform(words); |
| |
| output.apply(Log.ofElements()); |
| |
| pipeline.run(); |
| } |
| |
| static PCollection<KV<String, String>> applyTransform(PCollection<String> input) { |
| return input |
| .apply(WithKeys.<String, String>of(fruit -> fruit.substring(0, 1)) |
| .withKeyType(strings())); |
| } |
| |
| } |