/**
  * Return a <code>ToStringOption</code> instance with {@link #appendStatic} option set. if the
  * current instance is not {@link #DEFAULT_OPTION default instance} then set on the current
  * instance and return the current instance. Otherwise, clone the default instance and set on the
  * clone and return the clone
  *
  * @param appendStatic
  * @return this option instance or clone if this is the {@link #DEFAULT_OPTION}
  */
 public ToStringOption setAppendStatic(boolean appendStatic) {
   ToStringOption op = this;
   if (this == DEFAULT_OPTION) {
     op = new ToStringOption(this.appendStatic, this.appendTransient);
   }
   op.appendStatic = appendStatic;
   return op;
 }
 /**
  * Return a <code>ToStringOption</code> instance with {@link #upToClass} option set. if the
  * current instance is not {@link #DEFAULT_OPTION default instance} then set on the current
  * instance and return the current instance. Otherwise, clone the default instance and set on the
  * clone and return the clone
  *
  * @param c
  * @return this option instance or clone if this is the {@link #DEFAULT_OPTION}
  */
 public ToStringOption setUpToClass(Class<?> c) {
   ToStringOption op = this;
   if (this == DEFAULT_OPTION) {
     op = new ToStringOption(this.appendStatic, this.appendTransient);
   }
   op.upToClass = c;
   return op;
 }