RSS 2.0
Sign In
# Sunday, 09 May 2010
Ribbon of Saint George

We're facing a task of parsing reports produced from legacy applications and converting them into a structured form, e.g. into xml. These xml files can be processed further with up to date tools to produce good looking reports.

Reports at hands are of very different structure and of size: from a couple of KB to a several GB. The good part is that they mostly have a tabular form, so it's easy to think of specific parsers in case of each report type.

Our goal is to create an environment where a less qualified person(s) could create and manage such parsers, and only rarely to engage someone who will handle less untrivial cases.

Our analysis has shown that it's possible to write such parser in almost any language: xslt, C#, java.

Our approach was to create an xml schema annotations that from one side define a data structure, and from the other map report layout. Then we're able to create an xslt that will generate either xslt, C#, or java parser according to the schema definitions. Because of languages xom, providing XML Object Model and serialization stylesheets for C# and java, it does not really matter what we shall generate xslt or C#/java, as code will look the same.

The approach we're going to use to describe reports is not as powerfull as conventional parsers. Its virtue, however, is simplicity of specification.

Consider a report sample (a data to extract is in bold):

1 TITLE ...                    PAGE:            1
 BUSINESS DATE: 09/30/09   ... RUN DATE: 02/23/10
 CYCLE : ITD      RUN: 001 ... RUN TIME: 09:22:39

        CM         BUS   ...
  CO    NBR  FRM   FUNC  ...
 ----- ----- ----- -----  
 XXX   065   065   CLR   ...
 YYY   ...
...
1 TITLE ...                    PAGE:            2
 BUSINESS DATE: 09/30/09   ... RUN DATE: 02/23/10
 CYCLE : ITD      RUN: 001 ... RUN TIME: 09:22:39

        CM         BUS   ...
  CO    NBR  FRM   FUNC  ...
 ----- ----- ----- -----  
 AAA   NNN   MMM   PPP   ...
 BBB   ...
...

* * * * *  E N D   O F   R E P O R T  * * * * *

We're approaching to the report through a sequence of views (filters) of this report. Each veiw localizes some report data either for the subsequent filterring or for the extraction of final data.

Looking into the example one can build following views of the report:

  1. View of data before the "E N D   O F   R E P O R T" line.
  2. View of remaining data without page headers and footers.
  3. Views of table rows.
  4. Views of cells.

A sequence of filters allows us to build a pipeline of transformations of original text. This also allows us to generate a clean xslt, C# or java code to parse the data.

At first, our favorite language for such parser was xslt. Unfortunatelly, we're dealing with Saxon xslt implementation, which is not very strong in streaming processing. Without a couple of extension functions to prevent caching, it tends to cache whole input in the memory, which is not acceptable.

At present we have decided to start from C# code, which is pure C# naturally. :-)

Code still is in the development but at present we would like to share the xml schema annotations describing report layout: report-mapping.xsd, and a sample of report description: test.xsd.

Sunday, 09 May 2010 05:18:57 UTC  #    Comments [0] -
Announce | Thinking aloud | xslt
All comments require the approval of the site owner before being displayed.
Name
E-mail
Home page

Comment (Some html is allowed: a@href@title, b, blockquote@cite, em, i, strike, strong, sub, super, u) where the @ means "attribute." For example, you can use <a href="" title=""> or <blockquote cite="Scott">.  

[Captcha]Enter the code shown (prevents robots):

Live Comment Preview
Archive
<2024 March>
SunMonTueWedThuFriSat
252627282912
3456789
10111213141516
17181920212223
24252627282930
31123456
Statistics
Total Posts: 386
This Year: 2
This Month: 0
This Week: 0
Comments: 931
Locations of visitors to this page
Disclaimer
The opinions expressed herein are our own personal opinions and do not represent our employer's view in anyway.

© 2024, Nesterovsky bros
All Content © 2024, Nesterovsky bros
DasBlog theme 'Business' created by Christoph De Baene (delarou)