FpML Issues Tracker

407: offsets in MinuteHourTime

July 25, 2007

closed

Minor

Always

Schema

Admin

mgratacos

Summary

All,

We have a simple type that we use for exercise times called HourMinuteTime

A type defining a time specified in hh:mm:ss format where the second component must be '00', e.g. 11am would be represented as 11:00:00.

Shouldnt this type allow the support for time offsets (i.e. +00:00)?

Notes:

  • mgratacos

    07/25/07 9:30 am

    According to the FpML Architecture it should; and we should follow the Architecture.
    Matthew

  • mgratacos

    07/25/07 9:38 am

    I propose to amend the simple type to allow a time offset:



    A type defining a time specified in hh:mm:ss format where the second component must be ’00’, e.g. 11am would be represented as 11:00:00.




    Let me know if there is any objection to this.

    Kind regards,
    Marc

  • mgratacos

    07/26/07 7:15 am

    The purpose of the pattern is constrain the seconds value to “:00”. In the
    absence of a documented rationale, I guess the author either overlooked or
    disregarded the optional time zone indicator. Presumably this has not been
    raised as an issue until now, because the only instance of the type occurs
    in association with a businessCenter (within type BusinessCenterTime),
    which implicitly localises the time.

    Where the time zone indicator is produced, it must be consistent with the
    quoted businessCenter – does this imply the need for a validation rule
    (easy to express in conceptual terms, harder to implement)?

    NB: if we permit timezone offsets, we also have to support the UTC
    indicator (“Z” suffix).

    Best regards,
    Harry

  • mgratacos

    07/26/07 7:16 am

    Harry,

    To implement this rule we’d need an external source with business centers and their corresponding time offsets. I am not sure how practical that is in terms of implementation.

    Wouldn’t be much simpler in terms of processing to rely on explicit offsets (and maybe enforce its use in this case) instead of business centers? Obviously, implemented in version 5.0. Then, the question is whether we allow both in the 4.x versions.

    Thanks,
    -Marc

  • mgratacos

    07/26/07 7:16 am

    Offsets are not timezones. Any offset can legally be used for any timezone.
    Matthew

  • mgratacos

    07/26/07 7:17 am

    Marc,

    Please see my responses (HMcA>) below.

    Best regards,
    Harry

    Harry,

    To implement this rule we’d need an external source with business centers
    and their corresponding time offsets. I am not sure how practical that is
    in terms of implementation.

    HMcA> That’s what I meant by “harder to implement”

    Wouldn’t be much simpler in terms of processing to rely on explicit offsets
    (and maybe enforce its use in this case) instead of business centers?
    Obviously, implemented in version 5.0. Then, the question is whether we
    allow both in the 4.x versions.

    HMcA> Simpler to process perhaps – but if we replace businessCenter with a
    timezone offset, we lose information present in the legal documentation
    e.g. an exercise time expressed in the confirm as “09:00 a.m. London time”.
    I’m not sure if this is acceptable.

  • mgratacos

    07/26/07 7:17 am

    Must be a slow morning …

    The W3C recommendation on date/time representation is based on ISO 8601,
    which provides for times expressed either in UTC, or in local time with a
    time zone offset relative to UTC. There are no local timezone designators
    as such. In this sense, offsets and timezones are equivalent, because the
    offset in a dateTime expression is *always* relative to UTC.

    From the specification*:

    3.2.7.3 Timezones

    Timezones are durations with (integer-valued) hour and minute properties
    (with the hour magnitude limited to at most 14, and the minute magnitude
    limited to at most 59, except that if the hour magnitude is 14, the minute
    value must be 0); they may be both positive or both negative.

    The lexical representation of a timezone is a string of the form: ((‘+’ |
    ‘-‘) hh ‘:’ mm) | ‘Z’, where
    hh is a two-digit numeral (with leading zeros as required) that
    represents the hours,
    mm is a two-digit numeral that represents the minutes,
    ‘+’ indicates a nonnegative duration,
    ‘-‘ indicates a nonpositive duration.

    The mapping so defined is one-to-one, except that ‘+00:00’, ‘-00:00’, and
    ‘Z’ all represent the same zero-length duration timezone, UTC; ‘Z’ is its
    canonical representation.

    When a timezone is added to a UTC dateTime, the result is the date and time
    “in that timezone”. For example, 2002-10-10T12:00:00+05:00 is
    2002-10-10T07:00:00Z and 2002-10-10T00:00:00+05:00 is 2002-10-09T19:00:00Z.

    – I think that’s clear enough.

    Best regards,
    Harry

    (*W3C Recommendation 28 October 2004, XML Schema Part 2: Datatypes Second
    Edition)

  • mgratacos

    07/26/07 7:18 am

    Harry,

    I don’t see why we lose information. The information may be represented in a different format but I think it’s the same.

    10:00:00 ESMA = 10:00:00+01:00

    As I understood, Business Centers were applied to check calendars and roll dates for holidays. I don’t think they should be used to define a time zone.

  • mgratacos

    07/26/07 7:18 am

    I see your point that it needs to be checked from a legal side though.

  • mgratacos

    07/26/07 7:19 am

    Yes: the problem is not with the designation of the instant-of-time, but
    the identification of the location as per the relevant ISDA matrix (many
    locations may share the same timezone).
    HMcA

  • mgratacos

    07/26/07 7:19 am

    Marc,

    there is another dependency. If you start using business centres to
    drive time zones, and do it consistently across the standard, then you
    will have to put in business centres in adjustable dates even if no
    business day convention applies – and that breaks our validation rules.
    Alternatively, you lose consistency by making exceptions for certain
    locations in FpML.

    Regards,

    Christian

  • mgratacos

    07/26/07 7:19 am

    >> I guess the author either overlooked or disregarded the optional time
    zone indicator

    When the type was designed the corresponding time element would always
    have been used with a corresponding business center as Harry mentioned.
    This has always been the case in Rates. So for example, an expiration
    time may be defined as 11:00 New York time so the time would be
    specified as 11:00:00 and then the corresponding business center element
    would contain USNY. I don’t think allowing a timezone offset in these
    cases would be particularly helpful or desirable. Since specifying a
    time with a time zone offset doesn’t actually define which centre the
    time is applicable to and also won’t take into account daylight savings
    etc. since the offset will always be relative to GMT.

    Guy

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