Github user greghogan commented on a diff in the pull request: https://github.com/apache/flink/pull/2337#discussion_r77827675 --- Diff: flink-core/src/main/java/org/apache/flink/api/common/typeinfo/TypeInfoFactory.java --- @@ -0,0 +1,55 @@ +/* + * 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.api.common.typeinfo; + +import java.lang.reflect.Type; +import java.util.Map; +import org.apache.flink.annotation.Public; +import org.apache.flink.api.java.typeutils.TypeExtractor; + +/** + * Base class for implementing a type information factory. A type information factory allows for + * plugging-in user-defined {@link TypeInformation} into the Flink type system. The factory is + * called during the type extraction phase if the corresponding type has been annotated with + * {@link TypeInfo}. In a hierarchy of types the closest factory will be chosen while traversing + * upwards, however, a globally registered factory has highest precedence + * (see {@link TypeExtractor#registerFactory(Type, Class)}). + * + * @param <T> type for which {@link TypeInformation} is created + */ +@Public +public abstract class TypeInfoFactory<T> { + + public TypeInfoFactory() { + // default constructor --- End diff -- What is the reason for the empty no-arg constructor?
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