[Bug 1132] - fix access control rule ambiguities

[bugzilla-daemon@ecoinformatics.org]

http://bugzilla.ecoinformatics.org/show_bug.cgi?id=1132





------- Additional Comments From tao at nceas.ucsb.edu  2004-06-28 17:22 -------
I am thinking if we can get rid of reference in "access" module in eml2.1.0.
In eml2.1.0, the document for access will look like(The element name maybe wrong)
<eml><access>....</access>
     <dataAccess>
                <dataid>100</dataid>
                <dataid>200</dataid>
                <access>......</access>
     </dataAccess>
      <dataAccess>
                <dataid>300</dataid>
                <dataid>400</dataid>
                <access>......</access>
     </dataAccess>
</eml>

If the top level access module is a refernce to the access module in first
dataAccess, that means they have same access control. And this is a equivalent
access rules without reference:
<eml><access>real rules from access module from first dataAccess</access>.
     <dataAccess>
                <dataid>300</dataid>
                <dataid>400</dataid>
                <access>......</access>
     </dataAccess>
<eml>

If the access module in first dataAccess is a reference to top level access. It
makes no sense because the access rules in first dataAccess doesn't give more
rules for distribution than top access rule. The equivalent rules can be: 
eml><access>...</access>.
     <dataAccess>
                <dataid>300</dataid>
                <dataid>400</dataid>
                <access>......</access>
     </dataAccess>
<eml>

If the access module in frist dataAccess is a refernce to second dataAccess, we
can revise the rules to:
eml><access>...</access>.
     <dataAccess>
                <dataid>100</dataid>
                 <dataid>200</dataid>
                <dataid>300</dataid>
                <dataid>400</dataid>
                <access>......</access>
     </dataAccess>
<eml>

So without reference, we still can make access module reusable(like the above
description). And if we get rid of reference, it will make implementation  simpler.

Any comments and suggestions are appreciated.