sanha commented on a change in pull request #115: [NEMO-96] Modularize DataSkewPolicy to use MetricVertex and BarrierVertex URL: https://github.com/apache/incubator-nemo/pull/115#discussion_r214376305
########## File path: common/src/main/java/edu/snu/nemo/common/coder/KVEncoderFactory.java ########## @@ -0,0 +1,88 @@ +/* + * Copyright (C) 2018 Seoul National University + * + * Licensed 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 edu.snu.nemo.common.coder; + +import java.io.IOException; +import java.io.OutputStream; + +/** + * A kv encoder factory object which generates kv encoders that encode values of type {@code T} into byte streams. + * To avoid to generate instance-based coder such as Spark serializer for every encoding, + * user need to explicitly instantiate an kv encoder instance and use it. + * + * @param <T> element type. + */ +public interface KVEncoderFactory<T> extends EncoderFactory { + @Override + KVEncoder<T> create(OutputStream outputStream) throws IOException; + EncoderFactory getKeyEncoderFactory(); + + /** + * Interface of the Encoder. + * + * @param <T> element type. + */ + interface KVEncoder<T> extends Encoder<T> { + /** + * Encodes the given value onto the specified output stream. + * It has to be able to encode the given stream consequently by calling this method repeatedly. + * Because the user may want to keep a single output stream and continuously concatenate elements, + * the output stream should not be closed. + * + * @param element the element to be encoded + * @throws IOException if fail to encode + */ + void encode(T element) throws IOException; + } + + /** + * Dummy kv encoder factory. + */ + KVEncoderFactory DUMMY_KVENCODER_FACTORY = new DummyKVEncoderFactory(); + + /** + * Dummy kv encoder factory implementation which is not supposed to be used. + */ + final class DummyKVEncoderFactory implements KVEncoderFactory { + private final EncoderFactory keyEncoderFactory = null; Review comment: Ditto. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] With regards, Apache Git Services
