Hi,
discussing "Component Search Criteria":
In general I agree.
The criteria "change to a component
does not change other XML" is a little bit tricky.
Some examples why I think it is tricky:
(A) A deletion of a paragraph element
(<text:p> or <text:h> element) will have influence on the content
of a <text:paragraph-count> element elsewhere in the document.
(B) A deletion of a paragraph element
of type heading (<text:h element) might have influence on the content
of a <text:table-of-content> element elsewhere in the document.
(C) A change of the content of a paragraph
which is part of a list might have influence on the content of <text:bookmark-ref>
element which is cross-referencing this paragraph.
(D) A change to table cell content in
a spreadsheet document might have influece on the content of other table
cell's content which reference this table cell.
(E) ...
I do not think that these examples will
hinder us to define a <text:p> element as the root of a component.
But I think we need to 'tune' the "Component
Search Criteria" to reflect such 'on the component's state depending
XML changes'.
Mit freundlichen Grüßen / Best regards
Oliver-Rainer Wittmann
--
Advisory Software Engineer
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IBM Deutschland
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From:
Svante Schubert <>
To:
""
<>,
Date:
27.03.2013 11:33
Subject:
[office-collab]
Defining the Basics: The Search for Components
Sent by:
<>
The Search for Components
Search via Document Schemas
Instead of searching in every document at hand for components,
the schema might be searched for components instead, as all given possibilities
are automatically covered. An automated reading of the schema - perhaps
with a visualization in a front-end to analyze the XML - might be very
helpful as nowadays formats turn out to be quite complex
1
.
Optimal would be a web based application to be able to decentralize the
work in sorting out the XML elements to components
2
.
Component Search Criteria
A component is similar to a puzzle piece of a document,
some logical unit, which consists of one or more XML elements, which are
usually connected, but do not have to be (depends on the decision of the
XML file format designer). The only rule is that the component have to
be disjoint to other components. This means if the data or the state of
the component is being changed, no other component’s data have to be changed
(aside implicitly the parent). In other words by changing the components
existing XML (element, attribute or text) or XML that is related to it,
no other component as the containing component will change it state. The
containing component changes its state as if for instance an image is being
delete from the document, the document is changing as well, but no other
component as other images, tables at a different place will change. Therefore
if a component is being deleted, all XML (joint or spread over the XML
file(s)) have to be deleted as a whole. Components usually have a specific
XML element they start with “component root element”, like in ODF <text:p>
for a paragraph. If the component may consists of multiple XML elements
there are as well “component leave elements”. For instance, in ODF an
image consists of the <draw:frame>, which provides the visual view
size and the <draw:image> element containing the loadable graphic,
while in HTML there is only a single <img/> element.
Often there is a lot of boilerplate XML elements in a format,
which are not being mapped to a format. For instance, the components of
an ODF text document are starting among <office:document>/<office:body>/<office:text>
All child elements of <office:text> are root components
of the text document.
Similar to solving a Sudoku riddle it is best to solve
the easy parts first and name the obvious components first. Aside of those
root components, the components that are usually added by users via their
applications are good starting points for an empiric approach.
When a component was found the “component root elements”
(and in case of multi-element components either the ending “component
leave elements” or if they are not easy to determine to mark the elements
within the component named as “component trunk elements”) are best marked
directly in the XML Schema. For instance in XML RelaxNG Schema using annotations
3
.
Referencing Components
A component within the component tree is referenced by
its position. Similar to an URL position and identification should be the
same. Components of all types (table, paragraph or character) should be
handled equally when referenced by their position to allow an easy generic
access. The root of the document would be “/” in the serialized string
representing the position. All their children are counted by document order
and representing by their document child position as an integer. For instance,
the first component being a paragraph would be accessed via “/1”. The
third character within this child paragraph would be accessed via “/1/3”.
If there is a table after the paragraph, the fifth paragraph within the
4 th cell of the 3 rd row, would be accessed via “/2/3/4/5”.
Every component position can be mapped to its XML position.
Programming Guidance:
The creation of a specific component tree can be easily accomplished during
the load of an XML document by implementing/overwriting the
SAX
ContentHandler interface
. By overwriting the
startElement, endElement and characters methods, all XML elements being
component root elements, component delimiters and text can be gathered
and mapped to operation calls (only sequential adding (e.g. no deletion,
merge, split) during loading a document).
1
The document formats are very complex. The ODF 1.2 part 1 for instance
counts about 600 XML elements and about 1300 XML attributes, not to mention
the different attribute values possible, e.g. to express styles. See
http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html
2
The
document formats are very complex. The ODF 1.2 part 1 for instance counts
about 600 XML elements and about 1300 XML attributes, not to mention the
different attribute values possible, e.g. to express styles. See
http://docs.oasis-open.org/office/v1.2/os/OpenDocument-v1.2-os-part1.html
3
http://relaxng.org/tutorial-20011203.html#IDA1OZR
