content: /*
   * 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.kafka.streams.state;
  
  import org.apache.kafka.streams.KeyValue;
  
  import java.util.Objects;
  
  /**
   * Combines a value from a {@link KeyValue} with a timestamp.
   *
   * @param <V>
   */
  public final class ValueAndTimestamp<V> {
      private final V value;
      private final long timestamp;
  
      private ValueAndTimestamp(final V value,
                                final long timestamp) {
          this.value = value;
          this.timestamp = timestamp;
      }
  
      /**
       * Create a new {@link ValueAndTimestamp} instance if the provided {@code value} is not {@code null}.
       *
       * @param value      the value
       * @param timestamp  the timestamp
       * @param <V> the type of the value
       * @return a new {@link ValueAndTimestamp} instance if the provided {@code value} is not {@code null};
       *         otherwise {@code null} is returned
       */
      public static <V> ValueAndTimestamp<V> make(final V value,
                                                  final long timestamp) {
          return value == null ? null : new ValueAndTimestamp<>(value, timestamp);
      }
  
      /**
       * Create a new {@link ValueAndTimestamp} instance. The provided {@code value} may be {@code null}.
       *
       * @param value      the value
       * @param timestamp  the timestamp
       * @param <V> the type of the value
       * @return a new {@link ValueAndTimestamp} instance
       */
      public static <V> ValueAndTimestamp<V> makeAllowNullable(
          final V value, final long timestamp) {
          return new ValueAndTimestamp<>(value, timestamp);
      }
  
      /**
       * Return the wrapped {@code value} of the given {@code valueAndTimestamp} parameter
       * if the parameter is not {@code null}.
       *
       * @param valueAndTimestamp a {@link ValueAndTimestamp} instance; can be {@code null}
       * @param <V> the type of the value
       * @return the wrapped {@code value} of {@code valueAndTimestamp} if not {@code null}; otherwise {@code null}
       */
      public static <V> V getValueOrNull(final ValueAndTimestamp<V> valueAndTimestamp) {
          return valueAndTimestamp == null ? null : valueAndTimestamp.value();
      }
  
      public V value() {
          return value;
      }
  
      public long timestamp() {
          return timestamp;
      }
  
      @Override
      public String toString() {
          return "<" + value + "," + timestamp + ">";
      }
  
      @Override
      public boolean equals(final Object o) {
          if (this == o) {
              return true;
          }
          if (o == null || getClass() != o.getClass()) {
              return false;
          }
          final ValueAndTimestamp<?> that = (ValueAndTimestamp<?>) o;
          return timestamp == that.timestamp &&
              Objects.equals(value, that.value);
      }
  
      @Override
      public int hashCode() {
          return Objects.hash(value, timestamp);
      }
  }
  