| /** |
| * 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.crunch.types; |
| |
| import java.io.Serializable; |
| |
| import org.apache.crunch.DoFn; |
| |
| /** |
| * Converts the input key/value from a MapReduce task into the input to a |
| * {@link DoFn}, or takes the output of a {@code DoFn} and write it to the |
| * output key/values. |
| */ |
| public interface Converter<K, V, S, T> extends Serializable { |
| S convertInput(K key, V value); |
| |
| T convertIterableInput(K key, Iterable<V> value); |
| |
| K outputKey(S value); |
| |
| V outputValue(S value); |
| |
| Class<K> getKeyClass(); |
| |
| Class<V> getValueClass(); |
| |
| /** |
| * If true, convert the inputs or outputs from this {@code Converter} instance |
| * before (for outputs) or after (for inputs) using the associated PType#getInputMapFn |
| * and PType#getOutputMapFn calls. |
| */ |
| boolean applyPTypeTransforms(); |
| } |