| /* |
| * 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.beam.sdk.transforms; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.Collection; |
| import java.util.Collections; |
| import java.util.Set; |
| import org.apache.beam.sdk.annotations.Experimental; |
| import org.apache.beam.sdk.annotations.Experimental.Kind; |
| import org.apache.beam.sdk.values.PCollectionView; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.collect.Sets; |
| |
| /** Describes the run-time requirements of a {@link Contextful}, such as access to side inputs. */ |
| @Experimental(Kind.CONTEXTFUL) |
| public final class Requirements implements Serializable { |
| private final Collection<PCollectionView<?>> sideInputs; |
| |
| private Requirements(Collection<PCollectionView<?>> sideInputs) { |
| this.sideInputs = sideInputs; |
| } |
| |
| /** The side inputs that this {@link Contextful} needs access to. */ |
| public Collection<PCollectionView<?>> getSideInputs() { |
| return sideInputs; |
| } |
| |
| /** Describes the need for access to the given side inputs. */ |
| public static Requirements requiresSideInputs(Collection<PCollectionView<?>> sideInputs) { |
| return new Requirements(sideInputs); |
| } |
| |
| /** Like {@link #requiresSideInputs(Collection)}. */ |
| public static Requirements requiresSideInputs(PCollectionView<?>... sideInputs) { |
| return requiresSideInputs(Arrays.asList(sideInputs)); |
| } |
| |
| /** Describes an empty set of requirements. */ |
| public static Requirements empty() { |
| return new Requirements(Collections.emptyList()); |
| } |
| |
| /** Whether this is an empty set of requirements. */ |
| public boolean isEmpty() { |
| return sideInputs.isEmpty(); |
| } |
| |
| public static Requirements union(Contextful... contextfuls) { |
| Set<PCollectionView<?>> sideInputs = Sets.newHashSet(); |
| for (Contextful c : contextfuls) { |
| sideInputs.addAll(c.getRequirements().getSideInputs()); |
| } |
| return requiresSideInputs(sideInputs); |
| } |
| } |