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 accord.utils;
  
  import java.util.function.BiPredicate;
  import java.util.function.Function;
  
  import accord.primitives.Timestamp;
  
  public class Timestamped<T>
  {
      public final Timestamp timestamp;
      public final T data;
      private final Function<? super T, ? extends String> toString;
  
      public Timestamped(Timestamp timestamp, T data, Function<? super T, ? extends String> toString)
      {
          this.timestamp = timestamp;
          this.data = data;
          this.toString = toString;
      }
  
      public static <T> Timestamped<T> merge(Timestamped<T> a, Timestamped<T> b)
      {
          return a.timestamp.compareTo(b.timestamp) < 0 ? b : a;
      }
  
      public static <T> Timestamped<T> merge(Timestamped<T> a, Timestamped<T> b, BiPredicate<T, T> testPrefix, BiPredicate<T, T> testEquality)
      {
          int c = a.timestamp.compareTo(b.timestamp);
          int c2 = Long.compare(a.timestamp.uniqueHlc(), b.timestamp.uniqueHlc());
          Invariants.require(normaliseCmp(c) == normaliseCmp(c2));
          validateCmp(c, a, b, testPrefix, testEquality, true);
          validateCmp(c2, a, b, testPrefix, testEquality, true);
          return c >= 0 ? a : b;
      }
  
      private static int normaliseCmp(int c)
      {
          return c < 0 ? -1 : c > 0 ? 1 : 0;
      }
  
      public static <T> Timestamped<T> mergeNew(Timestamped<T> a, Timestamped<T> b, BiPredicate<T, T> testPrefix, BiPredicate<T, T> testEquality)
      {
          int c = a.timestamp.compareTo(b.timestamp);
          validateCmp(c, a, b, testPrefix, testEquality, false);
          validateCmp(Long.compare(a.timestamp.uniqueHlc(), b.timestamp.uniqueHlc()), a, b, testPrefix, testEquality, false);
          return c >= 0 ? a : b;
      }
  
      private static <T> void validateCmp(int cmp, Timestamped<T> a, Timestamped<T> b, BiPredicate<T, T> testPrefix, BiPredicate<T, T> testEquality, boolean permitBackwards)
      {
          if (cmp == 0) Invariants.requireArgument(testEquality.test(a.data, b.data), "%s != %s", a, b);
          else if (cmp < 0) Invariants.requireArgument(testPrefix.test(a.data, b.data), "%s >= %s", a, b);
          else if (permitBackwards) Invariants.requireArgument(testPrefix.test(b.data, a.data), "%s <= %s", a, b);
          else Invariants.illegalState("Trying to write old data %s < %s", b, a);
      }
  
      public static <T> Timestamped<T> mergeEqual(Timestamped<T> a, Timestamped<T> b, BiPredicate<T, T> testEquality)
      {
          int c = a.timestamp.compareTo(b.timestamp);
          Invariants.require(c == 0 && testEquality.test(a.data, b.data), "%s != %s", a, b);
          return a;
      }
  
      @Override
      public String toString()
      {
          return toString.apply(data);
      }
  
      public boolean equals(Timestamped<T> that, BiPredicate<T, T> equality)
      {
          return this.timestamp.equals(that.timestamp) && equality.test(this.data, that.data);
      }
  }
  