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package com.techempower.helper;

import java.util.*;

/**
 * Provides simple utility functionality that works on basic Objects and
 * Comparables.  These functions simply don't really align with any of the
 * other Helper classes.
 */
public final class ObjectHelper
{

  /**
   * Compares the two objects avoiding null pointer exceptions.  If
   * both objects are null, this method returns 0.  Otherwise,
   * if a is null, -1 is returned. Otherwise, if b is null, 1 is returned.
   * If neither object is null, the result of a.compareTo(b) is
   * returned.
   *
   * @param  a class that implements Comparable<? super T>,
   *    meaning that instances of the class are either comparable to other
   *    instances of the class (the simple case of ? = T) or to
   *    instances of some super class of T.
   * @param a a comparable object
   * @param b a comparable object
   * @return a negative integer, zero, or a positive integer as
   *    the first object is less than, equal to, or greater than
   *    the second object
   */
  public static > int compare(T a, T b)
  {
    return a == null ? b == null ? 0 : -1 : b == null ? 1 : a.compareTo(b);
  }

  /**
   * Compares the two objects avoiding null pointer exceptions, using a
   * provided comparator. If both objects are null, this method
   * returns 0. Otherwise, if a is null, -1 is returned. Otherwise, if b is
   * null, 1 is returned. If neither object is null, the result of
   * a.compareTo(b) is returned.
   *
   * @param  a class that is comparable by the given comparator.
   * @param a a comparable object
   * @param b a comparable object
   * @param comparator a comparator to use
   * @return a negative integer, zero, or a positive integer as the first
   * object is less than, equal to, or greater than the second object
   */
  public static  int compare(T a, T b, Comparator comparator)
  {
    return a == null ? b == null ? 0 : -1 : b == null ? 1 : comparator.compare(a, b);
  }

  /**
   * You may not instantiate this class.
   */
  private ObjectHelper()
  {
    // Does nothing.
  }
 
}