ex00 commented on a change in pull request #8402: [FLINK-12473][ml] Add the interface of ML pipeline and ML lib URL: https://github.com/apache/flink/pull/8402#discussion_r285383592
########## File path: flink-ml/flink-ml-api/src/main/java/org/apache/flink/ml/api/core/PipelineStage.java ########## @@ -0,0 +1,70 @@ +/* + * 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.flink.ml.api.core; + +import org.apache.flink.ml.api.misc.param.ParamInfo; +import org.apache.flink.ml.api.misc.param.WithParams; +import org.apache.flink.ml.api.misc.persist.Persistable; +import org.apache.flink.ml.util.param.ExtractParamInfosUtil; +import org.apache.flink.ml.util.persist.MLStageFactory; + +import com.google.gson.Gson; +import com.google.gson.JsonObject; + +import java.io.Serializable; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * Base class for a stage in a pipeline. The interface is only a concept, and does not have any + * actual functionality. Its subclasses must be either Estimator or Transformer. No other classes + * should inherit this interface directly. + * + * <p>Each pipeline stage is with parameters and meanwhile persistable. + * + * @param <T> The class type of the PipelineStage implementation itself, used by {@link + * org.apache.flink.ml.api.misc.param.WithParams} + * @see WithParams + */ +interface PipelineStage<T extends PipelineStage<T>> extends WithParams<T>, Serializable, + Persistable { + + default String toJson() { Review comment: +1 to rename methods for serialization/deserialization model stages. If we would want to support other formats for e.g. PMML for serialization/deserialization, then toJson/fromJson doesn't match to logic in this case. I suggest move serialization/deserialization implementation of logic to separate object from direct implementation in this interface - and inject serializer/deserializer to pipeline object. I mean next ```java class ExampleTransformer implements Transformer<ExampleTransformer>{ .... public ExampleTransformer(PipelineSerializer implementationForSpecificFormat){ this.serializer=implementationForSpecificFormat; .... } .... public String serialization() { // renamed version of toJson() return this.serializer.serialize(this); } ..... //some approach with deserializer } ``` or move out serialization and deserialization methods from Pipeline objects at all. ```java Transformer example = new ExampleTransformer(); //actions with ExampleTransformer String serializedPipeline = new PipelineSerializer("supported_format_name_like_json").serialize(example); ``` I think this approach is more flexible for support different formats for serialization\deserialization pipelines and this the changes we can do in the next PR if community will approve this propolsal. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to 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
