UPD Mail Archive: UPD> EventHandlers

UPD Mail Archive: UPD> EventHandlers

UPD> EventHandlers

From: Norbert Schade (norbertschade@oaktech.com)
Date: Thu Jun 21 2001 - 10:25:24 EDT

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    Today's dtd files on the UPDF web site in

    I have manually removed the XML declaration line at the beginning from all dtd files. Please check it with your parsers now.

    I have an inofficial answer from TIBCO Extensibility:
    We are aware that XA places the XML declaration and a standard software imprint comment. The XML declaration is optional according to XML 1.0 specification, hence the reason for having it. I understand that some parsers may not be aware of the XML and as a result the declaration may become problematic. In other words, some parsers need to have it while others don't.
    This is only an excerpt. I do not consider this the solution of the problem. But we have to continue somehow. Further input very much appreciated.

    I have moved the TBD_CompositeFeatures and TBD_EventHandlers into the print features, where they consider in my view. The first version of the event handlers is almost finished and implemented in the files on the web.

    For now we have predefined ten events:

    JCL_Start and JCL_End
    These are the two events for the job wrapper. I expect the JobSetting elements to be handled here.

    PDL_Start and PDL_End
    These two events handle the start and end of the page description language, the real body of the print file.

    Media_Start and Media_End
    The media stands for the physical sheet.
    A duplex command might be a good example to appear in Media_Start.

    PhysicalPage_Start and PhysicalPage_End
    The front page is one physical page, the back side is the other one.

    LogicalPage_Start and LogicalPage_End
    These two events might be very optional and only used, when N-Up or Booklet are device features.

    Other events may be added on request.

    Sample Job:
    Imagine a 14 page job, with duplex and 6-Up settings. Pages 1 and 13 should be checked for Media_Start by the driver. Pages 1, 7 and 13 should be checked for PhysicalPage_Start. All pages should be checked for LogicalPage_Start.

    All events show the same structure.
    An event has at least one EventElement with an EventFeature attribute, a Redundant attribute and three elements PreCondition, PostCondition and Reset.
    The EventFeature will be selected from a list (list to be done). The various JobSetting elements will appear here at least.
    The Redundant attribute tells whether an EventFeature needs to be resend in every event even when the setting is unchanged. Default will be TRUE.
    We want to be able to set preconditions and postconditions per EventElement. This is meant for a sample like 'switch to GL mode, before sending a certain EventElement and switch back to raster after it', which could be implemented in PDL_Start. You would select the switch to and from GL mode in the ConditionFeature attribute (list to be done) and a enter a proper setting manually.
    You can specify that certain EventFeatures are to reset after a special EventFeature. In that case add at least one Reset element and select the feature in the ResetFeature list (list to be done).

    The explanations on the event handlers will move to the 'UPDF Functional Specification' eventually.

    Except for the three lists marked as to be done this is the final proposal for the events. As I said we may add other events in future.
    Now is the time to deliver your comments.
    One single item on my private list is, whether we want to predefine certain placeholders for installable options from third parties - especially for the JCL and PDL events. Or do we assume they will be satisfied by adding their proprietary commands at the beginning or the end of an event?

    I always considered the event handlers as one of our four pillars of the UPDF concept, although for a long time I couldn't present the ideas I had in mind. Now that we have something specified and written down (I did a short feasibility study with Jim Sommer already), I hope you feel as confident with it as I do.
    You may compare this with other concepts. In PPD files I am missing this type of information at all. In GPD files in section '4.4.5 Command Execution Order' you find some useful information and they do some good stuff there. But with all respect I think ours is a little smarter.

    Norbert Schade
    Principle Software Engineer
    Host Software Group
    Oak Technology, Inc.
    10 Presidential Way
    Woburn, MA 01801
    Phone: 1-781-638-7614
    Fax: 1-781-638-7555
    email: norbertschade@oaktech.com

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