| /* |
| * 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.wayang.core.types; |
| |
| import java.util.Objects; |
| import org.apache.wayang.core.util.ReflectionUtils; |
| |
| /** |
| * A data set is an abstraction of the Wayang programming model. Although never directly materialized, a data set |
| * keeps track of type and structure of data units being passed between operators. |
| */ |
| public class DataSetType<T> { |
| |
| /** |
| * Stands for the absence of an actual instance. |
| */ |
| public static final DataSetType<Void> NONE = DataSetType.createDefault(Void.class); |
| |
| /** |
| * Stands for the absence of an actual instance. |
| */ |
| public static final DataSetType<Iterable<Void>> GROUPED_NONE = DataSetType.createGrouped(Void.class); |
| |
| /** |
| * Type of the data units within the data set. |
| */ |
| private final DataUnitType<T> dataUnitType; |
| |
| /** |
| * Creates a flat data set that contains basic data units. This is the normal case. |
| */ |
| public static <T> DataSetType<T> createDefault(Class<? extends T> dataUnitClass) { |
| return new DataSetType<>(new BasicDataUnitType<>(ReflectionUtils.generalize(dataUnitClass))); |
| } |
| |
| /** |
| * Creates a flat data set that contains basic data units. This is the normal case. |
| */ |
| public static <T> DataSetType<T> createDefault(BasicDataUnitType<T> dataUnitType) { |
| return new DataSetType<>(dataUnitType); |
| } |
| |
| /** |
| * Creates a flat data set that contains basic data units. This is the normal case. |
| */ |
| public static <T> DataSetType<T> createDefaultUnchecked(Class<?> dataUnitClass) { |
| return new DataSetType<>(new BasicDataUnitType<>(dataUnitClass).unchecked()); |
| } |
| |
| /** |
| * Creates a data set that contains groups of data units. |
| */ |
| public static <T> DataSetType<Iterable<T>> createGrouped(Class<? extends T> dataUnitClass) { |
| return new DataSetType<>(new DataUnitGroupType<>(new BasicDataUnitType<>(dataUnitClass))); |
| } |
| |
| /** |
| * Creates a new data set type that contains groups of data units. |
| */ |
| public static <T> DataSetType<Iterable<T>> createGrouped(BasicDataUnitType<T> inputType) { |
| return new DataSetType<>(new DataUnitGroupType<>(inputType)); |
| } |
| |
| /** |
| * Creates a data set that contains groups of data units. |
| */ |
| public static <T> DataSetType<Iterable<T>> createGroupedUnchecked(Class<?> dataUnitClass) { |
| return new DataSetType<>(new DataUnitGroupType<>(new BasicDataUnitType<>(dataUnitClass))); |
| } |
| |
| /** |
| * Returns a null type. |
| */ |
| public static DataSetType<Void> none() { |
| return NONE; |
| } |
| |
| /** |
| * Returns a grouped null type. |
| */ |
| public static DataSetType<Iterable<Void>> groupedNone() { |
| return GROUPED_NONE; |
| } |
| |
| |
| protected DataSetType(DataUnitType<T> dataUnitType) { |
| this.dataUnitType = dataUnitType; |
| } |
| |
| public DataUnitType<T> getDataUnitType() { |
| return this.dataUnitType; |
| } |
| |
| /** |
| * In generic code, we do not have the type parameter values of operators, functions etc. This method avoids casting issues. |
| * |
| * @return this instance with type parameters set to {@link Object} |
| */ |
| @SuppressWarnings("unchecked") |
| public DataSetType<Object> unchecked() { |
| return (DataSetType<Object>) this; |
| } |
| |
| /** |
| * In generic code, we do not have the type parameter values of operators, functions etc. This method avoids casting issues. |
| * |
| * @return this instance with type parameters set to {@link Iterable}{@code <}{@link Object}{@code >} |
| */ |
| @SuppressWarnings("unchecked") |
| public DataSetType<Iterable<Object>> uncheckedGroup() { |
| return (DataSetType<Iterable<Object>>) this; |
| } |
| |
| /** |
| * Checks whether this instance is more general that the given one, i.e., it is a valid type of datasets that are |
| * also valid under the given type. |
| * |
| * @param that the other instance |
| * @return whether this instance is a super type of {@code that} instance |
| */ |
| public boolean isSupertypeOf(DataSetType that) { |
| return this.dataUnitType.toBasicDataUnitType().isSupertypeOf(that.dataUnitType.toBasicDataUnitType()); |
| } |
| |
| /** |
| * Find out whether this corresponds to either {@link #none()} or {@link #groupedNone()}. |
| * |
| * @return whether above condition holds |
| */ |
| public boolean isNone() { |
| return this.equals(none()) || this.equals(groupedNone()); |
| } |
| |
| @Override |
| public boolean equals(Object o) { |
| if (this == o) return true; |
| if (o == null || this.getClass() != o.getClass()) return false; |
| DataSetType<?> that = (DataSetType<?>) o; |
| return Objects.equals(this.dataUnitType, that.dataUnitType); |
| } |
| |
| @Override |
| public int hashCode() { |
| return Objects.hash(this.dataUnitType); |
| } |
| |
| @Override |
| public String toString() { |
| return String.format("%s[%s]", this.getClass().getSimpleName(), this.dataUnitType); |
| } |
| } |