Request For Enhancement

[2001 JI Open Discussion]

By: Peter Kelley - yellekau

Request For Enhancement

2002-08-05 20:36

Recently the webwork open source project (now part of opensymphony) added Jasper Reports as a view technlogy to their MVC framework. The way this was done was to create a custom data source that read the results of webwork action execution. This allowed reports to be generated from the same data as web pages or XML documents with no change to the command logic.

 

In order to do this webwork uses the field name as a means to define what data to retrieve. Unfortunately this creates problems when field names contain characters invalid in Java identifiers such as the '.' character as the reports do not compile.

 

Would it be possible for Jasper Reports to add an optional attribute to the field tag called query which would then be included in field objects passed to data sources ? This would allow the data source to get the data without overloading the name attribute.

 

Peter Kelley

 

 

By: Teodor Danciu - teodord

RE: Request For Enhancement

2002-08-06 05:18

 

Hi,

 

The initial versions of the library allowed the use

of any name for fields, variables, groups, etc.

Then, in order to enhance speed when filling the

reports, I chose to give up using the name of the

fields to retrieve the field objects from the map

when evaluating expressions.

Instead, I declare normal Java variables using the

supplied field name, which I can use directly in the

report-generated class. This is why the field names

have to respect the Java naming conventions.

 

In other words, it's very easy to get back to the

older version that allowed the use of any name for

the report fields, the only problem would be that

this will slightly affect performance in report filling

process.

 

If you can organize a lobby for this,

I could accept it. :))

 

Lets hear what the others have to say about this.

 

Thank you,

Teodor

 

 

 

By: Peter Kelley - yellekau

RE: Request For Enhancement

2002-08-06 16:45

I think you misunderstand me. I'm not proposing any change in the way that names are handled.

 

The problem is that the name attribute is being used for two things: the name of the field and the query used to retrieve it from the data source. With SQL result sets this isn't a problem as the name of the field is the name of the column and so it can be returned. With other data sources, however, the name of the field and the query used to retrieve it from the data source can be quite different. By changing things back to the way they were before and allowing special characters in the name there is still no seperation between the name and the query.

 

What I am requesting is that an extra attribute query be added to both the XML report definition and the JRField interface. In this way the behavior and processing of the name field would remain unchanged for all data sources that only need the name. This would mean that the java variables could continue to use the name as before.

 

Data sources that needed to have extra information on how to retrieve the value of a field with a given name could then use the query attribute to retrieve the value.

 

My guess is that this would be a small change to make to the Jasper Reports code but it would mean a big increase in functionality for webwork.

 

Peter Kelley

 

 

By: Teodor Danciu - teodord

RE: Request For Enhancement

2002-08-08 01:33

 

Hi,

 

I think I got it now.

 

Then I suppose that adding a new optional element

called "fieldDescription" for the "field" element,

just like we already added "parameterDescription"

for the "parameter" element (check the DTD file to

see it, because I forgot to mention it in the docs),

would be exactly what you need.

 

In the parameters case, this description is used for

prompting purposes, but for fields you could use

the text there as the extra information you need for

extracting the field value in your special data sources.

 

Thank you,

Teodor

 

 

 

By: Peter Kelley - yellekau

RE: Request For Enhancement

2002-08-08 02:42

Exactly, this would be perfect. Thanks for your prompt response.

 

 

By: Peter Kelley - yellek

RE: Request For Enhancement

2002-10-01 20:56

I had a look at CVS recently to see if this feature (an optional fieldDescription element for the field tag) had been added bu the JRField interface did not seem to have been modified. Is this feature currently scheduled for a release any time soon ?

 

Peter Kelley

 

 

By: Teodor Danciu - teodord

RE: Request For Enhancement

2002-10-02 03:21

 

Hi,

 

This feature is in place for sometime now.

Have you checked the JRField.getDescription()

method?

 

Thank you,

Teodor