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.beam.sdk.values;
  
  import static org.apache.beam.vendor.guava.v32_1_2_jre.com.google.common.base.Preconditions.checkNotNull;
  
  import java.io.IOException;
  import java.io.InputStream;
  import java.io.OutputStream;
  import java.util.Arrays;
  import java.util.Collections;
  import java.util.List;
  import java.util.Objects;
  import org.apache.beam.sdk.coders.Coder;
  import org.apache.beam.sdk.coders.InstantCoder;
  import org.apache.beam.sdk.coders.StructuredCoder;
  import org.apache.beam.sdk.transforms.windowing.BoundedWindow;
  import org.checkerframework.checker.nullness.qual.Nullable;
  import org.joda.time.Instant;
  
  /**
   * An immutable pair of a value and a timestamp.
   *
   * <p>The timestamp of a value determines many properties, such as its assignment to windows and
   * whether the value is late (with respect to the watermark of a {@link PCollection}).
   *
   * @param <V> the type of the value
   */
  public class TimestampedValue<V extends @Nullable Object> {
    /**
     * Returns a new {@link TimestampedValue} with the {@link BoundedWindow#TIMESTAMP_MIN_VALUE
     * minimum timestamp}.
     */
    public static <V> TimestampedValue<V> atMinimumTimestamp(V value) {
      return of(value, BoundedWindow.TIMESTAMP_MIN_VALUE);
    }
  
    /** Returns a new {@code TimestampedValue} with the given value and timestamp. */
    public static <V> TimestampedValue<V> of(V value, Instant timestamp) {
      return new TimestampedValue<>(value, timestamp);
    }
  
    public V getValue() {
      return value;
    }
  
    public Instant getTimestamp() {
      return timestamp;
    }
  
    @Override
    public boolean equals(@Nullable Object other) {
      if (!(other instanceof TimestampedValue)) {
        return false;
      }
      TimestampedValue<?> that = (TimestampedValue<?>) other;
      return Objects.equals(value, that.value) && Objects.equals(timestamp, that.timestamp);
    }
  
    @Override
    public int hashCode() {
      return Objects.hash(value, timestamp);
    }
  
    @Override
    public String toString() {
      return "TimestampedValue(" + value + ", " + timestamp + ")";
    }
  
    /////////////////////////////////////////////////////////////////////////////
  
    /** A {@link Coder} for {@link TimestampedValue}. */
    public static class TimestampedValueCoder<T> extends StructuredCoder<TimestampedValue<T>> {
  
      private final Coder<T> valueCoder;
  
      public static <T> TimestampedValueCoder<T> of(Coder<T> valueCoder) {
        return new TimestampedValueCoder<>(valueCoder);
      }
  
      @Override
      public Object structuralValue(TimestampedValue<T> value) {
        Object structuralValue = valueCoder.structuralValue(value.getValue());
        return TimestampedValue.of(structuralValue, value.getTimestamp());
      }
  
      @SuppressWarnings("unchecked")
      TimestampedValueCoder(Coder<T> valueCoder) {
        this.valueCoder = checkNotNull(valueCoder);
      }
  
      @Override
      public void encode(TimestampedValue<T> windowedElem, OutputStream outStream)
          throws IOException {
        valueCoder.encode(windowedElem.getValue(), outStream);
        InstantCoder.of().encode(windowedElem.getTimestamp(), outStream);
      }
  
      @Override
      public TimestampedValue<T> decode(InputStream inStream) throws IOException {
        T value = valueCoder.decode(inStream);
        Instant timestamp = InstantCoder.of().decode(inStream);
        return TimestampedValue.of(value, timestamp);
      }
  
      @Override
      public void verifyDeterministic() throws NonDeterministicException {
        verifyDeterministic(
            this, "TimestampedValueCoder requires a deterministic valueCoder", valueCoder);
      }
  
      @Override
      public List<? extends Coder<?>> getCoderArguments() {
        return Arrays.<Coder<?>>asList(valueCoder);
      }
  
      public Coder<T> getValueCoder() {
        return valueCoder;
      }
  
      @Override
      public TypeDescriptor<TimestampedValue<T>> getEncodedTypeDescriptor() {
        return new TypeDescriptor<TimestampedValue<T>>() {}.where(
            new TypeParameter<T>() {}, valueCoder.getEncodedTypeDescriptor());
      }
  
      @Override
      public List<? extends Coder<?>> getComponents() {
        return Collections.singletonList(valueCoder);
      }
    }
  
    /////////////////////////////////////////////////////////////////////////////
  
    private final V value;
    private final Instant timestamp;
  
    protected TimestampedValue(V value, Instant timestamp) {
      checkNotNull(timestamp, "timestamp must be non-null");
  
      this.value = value;
      this.timestamp = timestamp;
    }
  }
  