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package com.spun.util;

import org.lambda.actions.Action0;
import org.lambda.actions.Action0WithException;
import org.lambda.functions.Function0WithException;
import org.lambda.query.Query;

import java.lang.reflect.Method;
import java.util.ArrayList;
import java.util.List;

/**
 * A static class of convenience functions for Manipulating objects
 **/
public class ObjectUtils
{
  public static Class loadClass(String className)
  {
    return throwAsError(() -> Class.forName(className, true, Thread.currentThread().getContextClassLoader()));
  }
  public static int generateHashCode(Object... relevantMembers)
  {
    final int PRIME = 31;
    int result = 1;
    for (Object member : relevantMembers)
    {
      result = PRIME * result + ((member == null) ? 0 : member.hashCode());
    }
    return result;
  }
  /**
   * tests if two objects are equal for all functions passed.
   **/
  public static boolean isEqualForMethods(Object o1, Object o2, String... methods)
  {
    try
    {
      Method[] m1 = getMethodsForObject(o1, methods);
      Method[] m2 = getMethodsForObject(o2, methods);
      for (int i = 0; i < m1.length; i++)
      {
        Object v1 = m1[i].invoke(o1, (Object[]) null);
        Object v2 = m2[i].invoke(o2, (Object[]) null);
        if (!isEqual(v1, v2))
        { return false; }
      }
      return true;
    }
    catch (Throwable t)
    {
      throw new Error(t);
    }
  }
  public static Method[] getMethodsForObject(Object o2, String[] passedMethods)
  {
    Method[] methods = new Method[passedMethods.length];
    Class clazz = o2.getClass();
    for (int i = 0; i < passedMethods.length; i++)
    {
      String methodName = passedMethods[i];
      Class[] parameters = null;
      methods[i] = throwAsError(() -> clazz.getMethod(methodName, parameters));
    }
    return methods;
  }
  /**
   * A convenience function to check if 2 strings are equal.
   **/
  public static boolean isEqual(Object s1, Object s2)
  {
    if (s1 == s2)
    {
      return true;
    }
    else if ((s1 != null) && s1.equals(s2))
    {
      return true;
    }
    else
    {
      return false;
    }
  }
  public static boolean isIn(Object target, Object[] objects)
  {
    for (int i = 0; i < objects.length; i++)
    {
      if (ObjectUtils.isEqual(objects[i], target))
      { return true; }
    }
    return false;
  }
  public static boolean isThisInstanceOfThat(Class thiz, Class that)
  {
    return that.isAssignableFrom(thiz);
  }
  public static Error throwAsError(Throwable t)
  {
    if (t instanceof RuntimeException)
    {
      throw (RuntimeException) t;
    }
    else if (t instanceof Error)
    {
      throw (Error) t;
    }
    else
    {
      throw new Error(t);
    }
  }
  public static  T getRandomIndex(T[] array)
  {
    if ((array == null) || (array.length == 0))
    { return null; }
    return array[NumberUtils.RANDOM.nextInt(array.length)];
  }
  public static Method getGreatestCommonDenominator(Object[] from, String methodName)
  {
    List> classes = new ArrayList<>();
    ArrayUtils.addArray(classes, getAllCastableClasses(from[0]));
    for (Object o : from)
    {
      for (int i = classes.size() - 1; i >= 0; i--)
      {
        Class clazz = classes.get(i);
        if (!isThisInstanceOfThat(o.getClass(), clazz) || !ClassUtils.hasMethod(clazz, methodName))
        {
          classes.remove(i);
        }
      }
    }
    return classes.size() == 0
        ? null
        : throwAsError(() -> ArrayUtils.getLast(classes).getMethod(methodName, (Class[]) null));
  }
  private static Class[] getAllCastableClasses(Object object)
  {
    Class clazz = object.getClass();
    ArrayList