| /* |
| * 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.basic.operators; |
| |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Optional; |
| import org.apache.commons.lang3.Validate; |
| import org.apache.wayang.core.api.Configuration; |
| import org.apache.wayang.core.optimizer.cardinality.CardinalityEstimator; |
| import org.apache.wayang.core.optimizer.cardinality.DefaultCardinalityEstimator; |
| import org.apache.wayang.core.plan.wayangplan.ElementaryOperator; |
| import org.apache.wayang.core.plan.wayangplan.UnarySource; |
| import org.apache.wayang.core.types.DataSetType; |
| |
| /** |
| * This source takes as input a Java {@link java.util.Collection}. |
| */ |
| public class CollectionSource<T> extends UnarySource<T> implements ElementaryOperator { |
| |
| protected final Collection<T> collection; |
| |
| public CollectionSource(Collection<T> collection, Class<T> typeClass) { |
| this(collection, DataSetType.createDefault(typeClass)); |
| } |
| |
| public CollectionSource(Collection<T> collection, DataSetType<T> type) { |
| super(type); |
| this.collection = collection; |
| } |
| |
| /** |
| * Copies an instance (exclusive of broadcasts). |
| * |
| * @param that that should be copied |
| */ |
| public CollectionSource(CollectionSource that) { |
| super(that); |
| this.collection = that.getCollection(); |
| } |
| |
| public Collection<T> getCollection() { |
| return this.collection; |
| } |
| |
| @Override |
| public Optional<CardinalityEstimator> createCardinalityEstimator( |
| final int outputIndex, |
| final Configuration configuration) { |
| Validate.inclusiveBetween(0, this.getNumOutputs() - 1, outputIndex); |
| return Optional.of(new DefaultCardinalityEstimator(1d, this.getNumInputs(), this.isSupportingBroadcastInputs(), |
| inputCards -> this.collection.size())); |
| } |
| |
| /** |
| * Creates a new instance without any data quanta. |
| */ |
| public static <T> CollectionSource<T> empty(Class<T> typeClass) { |
| final CollectionSource<T> instance = new CollectionSource<>(Collections.emptyList(), typeClass); |
| instance.setName("{}"); |
| return instance; |
| } |
| |
| /** |
| * Creates a new instance without any data quanta. |
| */ |
| public static <T> CollectionSource<T> singleton(T value, Class<T> typeClass) { |
| final CollectionSource<T> instance = new CollectionSource<>(Collections.singleton(value), typeClass); |
| instance.setName("{" + value + "}"); |
| return instance; |
| } |
| } |