public boolean containsValue( Object val ) {
    if( val == null ) return false;
    if( val == _val_1 ) return true; // Key 0
    for( TypeV V : values() )
      if( V == val || V.equals(val) )
        return true;
    return false;
  }
Returns <tt>true</tt> if this Map maps one or more keys to the specified
 value.  <em>Note</em>: This method requires a full internal traversal of the
 hash table and is much slower than {@link #containsKey}.
 @param val value whose presence in this map is to be tested
 @return <tt>true</tt> if this Map maps one or more keys to the specified value
 @throws NullPointerException if the specified value is null
jctools-core/src/main/java/org/jctools/maps/NonBlockingHashMapLong.java