| /* |
| * 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.values; |
| |
| import java.io.Serializable; |
| import java.util.Arrays; |
| import java.util.Comparator; |
| import java.util.Objects; |
| import javax.annotation.Nullable; |
| import org.apache.beam.sdk.transforms.Combine; |
| import org.apache.beam.sdk.transforms.GroupByKey; |
| import org.apache.beam.sdk.transforms.PTransform; |
| import org.apache.beam.sdk.transforms.SerializableComparator; |
| import org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.MoreObjects; |
| |
| /** |
| * An immutable key/value pair. |
| * |
| * <p>Various {@link PTransform PTransforms} like {@link GroupByKey} and {@link Combine#perKey} |
| * operate on {@link PCollection PCollections} of {@link KV KVs}. |
| * |
| * @param <K> the type of the key |
| * @param <V> the type of the value |
| */ |
| public class KV<K, V> implements Serializable { |
| /** Returns a {@link KV} with the given key and value. */ |
| public static <K, V> KV<K, V> of(@Nullable K key, @Nullable V value) { |
| return new KV<>(key, value); |
| } |
| |
| /** Returns the key of this {@link KV}. */ |
| public @Nullable K getKey() { |
| return key; |
| } |
| |
| /** Returns the value of this {@link KV}. */ |
| public V getValue() { |
| return value; |
| } |
| |
| ///////////////////////////////////////////////////////////////////////////// |
| |
| final @Nullable K key; |
| final @Nullable V value; |
| |
| private KV(@Nullable K key, @Nullable V value) { |
| this.key = key; |
| this.value = value; |
| } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (this == other) { |
| return true; |
| } |
| if (!(other instanceof KV)) { |
| return false; |
| } |
| KV<?, ?> otherKv = (KV<?, ?>) other; |
| // Arrays are very common as values and keys, so deepEquals is mandatory |
| return Objects.deepEquals(this.key, otherKv.key) |
| && Objects.deepEquals(this.value, otherKv.value); |
| } |
| |
| /** |
| * A {@link Comparator} that orders {@link KV KVs} by the natural ordering of their keys. |
| * |
| * <p>A {@code null} key is less than any non-{@code null} key. |
| */ |
| public static class OrderByKey<K extends Comparable<? super K>, V> |
| implements SerializableComparator<KV<K, V>> { |
| @Override |
| public int compare(KV<K, V> a, KV<K, V> b) { |
| if (a.key == null) { |
| return b.key == null ? 0 : -1; |
| } else if (b.key == null) { |
| return 1; |
| } else { |
| return a.key.compareTo(b.key); |
| } |
| } |
| } |
| |
| /** |
| * A {@link Comparator} that orders {@link KV KVs} by the natural ordering of their values. |
| * |
| * <p>A {@code null} value is less than any non-{@code null} value. |
| */ |
| public static class OrderByValue<K, V extends Comparable<? super V>> |
| implements SerializableComparator<KV<K, V>> { |
| @Override |
| public int compare(KV<K, V> a, KV<K, V> b) { |
| if (a.value == null) { |
| return b.value == null ? 0 : -1; |
| } else if (b.value == null) { |
| return 1; |
| } else { |
| return a.value.compareTo(b.value); |
| } |
| } |
| } |
| |
| @Override |
| public int hashCode() { |
| // Objects.deepEquals requires Arrays.deepHashCode for correctness |
| return Arrays.deepHashCode(new Object[] {key, value}); |
| } |
| |
| @Override |
| public String toString() { |
| return MoreObjects.toStringHelper(this).addValue(key).addValue(value).toString(); |
| } |
| } |