package com.github.davidmoten.guavamini;
   
   public final class Preconditions {
   
       private Preconditions() {
           // prevent instantiation
       }
   
       public static <T> T checkNotNull(T t) {
          return checkNotNull(t, null);
      }
  
      public static <T> T checkNotNull(T t, String message) {
          if (t == null)
              throw new NullPointerException(message);
          return t;
      }
      
      public static <T> T checkArgumentNotNull(T t) {
          return checkArgumentNotNull(t, "argument");
      }
      
      public static <T> T checkArgumentNotNull(T t, String parameterName) {
          if (t == null) {
              throw new IllegalArgumentException(parameterName + " cannot be null");
          } 
          return t;
      }
  
      public static void checkArgument(boolean b, String message) {
          if (!b)
              throw new IllegalArgumentException(message);
      }
  
      public static void checkArgument(boolean b) {
          if (!b)
              throw new IllegalArgumentException();
      }
  
  }