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/**
 * Copyright (c) The openTCS Authors.
 *
 * This program is free software and subject to the MIT license. (For details,
 * see the licensing information (LICENSE.txt) you should have received with
 * this copy of the software.)
 */
package org.opentcs.util;

import java.util.Comparator;
import org.opentcs.data.TCSObject;
import org.opentcs.data.TCSObjectReference;
import org.opentcs.data.order.TransportOrder;
import org.opentcs.data.peripherals.PeripheralJob;

/**
 * Some commonly used comparator implementations.
 */
public final class Comparators {

  /**
   * Prevents undesired instantiation.
   */
  private Comparators() {
  }

  /**
   * Returns a comparator for sorting TCSObjects lexicographically by their names.
   *
   * @return A comparator for sorting TCSObjects lexicographically by their names.
   */
  public static Comparator> objectsByName() {
    return Comparator.comparing(TCSObject::getName);
  }

  /**
   * Returns a comparator for sorting TCSObjectReferences lexicographically by their
   * names.
   *
   * @return A comparator for sorting TCSObjectReferences lexicographically by their
   * names.
   */
  public static Comparator> referencesByName() {
    return Comparator.comparing(TCSObjectReference::getName);
  }

  /**
   * A comparator for sorting transport orders by their deadlines, with the most urgent ones coming
   * first.
   * Transport orders are sorted by their deadlines first; if two orders have exactly the same
   * deadline, they are sorted by their (unique) creation times, with the older one coming first.
   *
   * @return A comparator for sorting transport orders by their deadlines.
   */
  public static Comparator ordersByDeadline() {
    return Comparator.comparing(TransportOrder::getDeadline).thenComparing(ordersByAge());
  }

  /**
   * A comparator for sorting transport orders by their age, with the oldest ones coming first.
   *
   * @return A comparator for sorting transport orders by their age.
   */
  public static Comparator ordersByAge() {
    return Comparator.comparing(TransportOrder::getCreationTime).thenComparing(objectsByName());
  }

  /**
   * A comparator for sorting peripheral jobs by their age, with the oldest ones coming first.
   *
   * @return A comparator for sorting peripheral jobs by their age.
   */
  public static Comparator jobsByAge() {
    return Comparator.comparing(PeripheralJob::getCreationTime).thenComparing(objectsByName());
  }
}