/// <summary>
/// Tests if this ObjectId starts with the given abbreviation.
/// </summary>
/// <param name="abbr">the abbreviation.</param>
/// <returns>
/// True if this ObjectId begins with the abbreviation; else false.
/// </returns>
public bool startsWith(AbbreviatedObjectId abbr)
{
return(abbr.prefixCompare(this) == 0);
}