How to create report using nested scripted datasets

Hi,
I'm pretty new to BIRT, been hacking around for about 6 months and all self-taught...so please be gentle with me if you think my question has an obvious or documented answer. I just haven't found it yet

Scenario:
 
I have a report that exclusively uses scripted datasets. The data is provided by a set of java classes that read and format data from a filesystem. The design of the report means that there is a lot of nesting of the BIRT components, for example,
 
List...contains a List... and a Table, and some of these have associated Groups to generate Table Of Content entries.
 
Question:
 
From the debugging I've done, it seems that many of my Open/Fetch/Close dataset events are executing concurrently, as I can see my debug statements interleaved. 
Is my conclusion correct, i.e. does BIRT build the scripted datasets in parallel?
 
If this is the case, then I have another question...
At a high level, my report, which describes a service, would be something like the following...
 
List
Detail - create an entry for each Operation in the service (supplied by dataset-A)
 List - create an entry for each parameter belonging to the Operation (supplied by dataset-B which is passed the value of the Operation name)
 Table - create a table of data structures relating to the parameter (supplied by dataset-C which is passed the value of the Operation Name)
 
I had assumed that BIRT would process the first Operation (from dataset-A), and then open dataset-B to get the parameters keyed by operation name, and then open dataset-C to get the data structure details.
That way, I would be able to pass the operation name to the open event of dataset-B and dataset-C via a variable.
 
However this is not working, and I suspect its due to the execution order not being as I assumed.
 
Any pointers you can give me on how to solve this problem is much appreciated.
 
Cheers!!

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Comments

mwilliams

I don't believe that all scripted data sets are executed in parallel. I believe they'd be the same as all other data sets, that they would execute as they're encountered in the report. What is your BIRT version? I'll take a look at nesting a scripted data set in another. Or if you could pass a simple example showing how you're doing it (using dummy data so I can actually run the report), that'd be great.

nomadau

Thanks for the offer of help Michael. 
It may be a bit of effort for me to set up an example that would make sense for you to run - I'll have a think about how I might do that. 
What you say about the order of processing datasets is consistent with how I was expecting my report to execute, so hopefully its something else I'm doing wrong that is causing this issue. 
Here's what I'm trying to achieve in my report.

- Service Description 
xxxxxx 
(List of service Operations) 
- Operation_A 
xxxxxxxx 
(List of parameters for Operation_A) 
 - request 
 (List of xpath expressions for request) 
 - xpath expression, type, cardinality, etc. 
 - xpath expression, type, cardinality, etc. 
 - response 
 (List of xpath expressions for response) 
 - xpath expression, type, cardinality, etc. 
 - xpath expression, type, cardinality, etc. 
- Operation_B 
xxxxx 
(List of parameters for Operation_B ) 
 - request 
 ..... same layout as shown above 
 - response 
 .....

My report has the following structure 
Body 
<Service Name and Description> 
List(1) - using Dataset1 (provides a list of operation names, keyed on the service value) 
 Detail 
 <Operation name and description> 
 List(2) - using Dataset2 (provides a list of parameter names, keyed on the operation/service values) 
 Detail 
 <parameter name and details> 
 List(3) - using Dataset3 (provides xpath data, keyed on the parameter/operation/service values) 
 <parameter xpath details>

The execution order I was expecting, aligns with what you say Michael, and would be something like this... 
open Dataset1 
fetch(1) for Dataset1 
open Dataset2 
fetch(1) for Dataset2 
 open Dataset3 
 fetch(1) for Dataset3 
 fetch(2) for Dataset3 
 close Dataset3 
fetch(2) for Dataset2 
... 
fetch(2) for Dataset1 
open Dataset2 
fetch(1) for Dataset2 
...and so on. 
This would mean that in the dataset open methods, I would have access to the key values (that were read from the parent dataset(s)) needed to create the nested datasets. 
For example, in open Dataset2 I should be able to access the operation name value that was read by the previous fetch Dataset1, i.e. (row["operationName"] and use this to construct the list of parameter names belonging to dataset2. 
However, I've put debug info in the open and fetch operations for all of my scripted datasets and I see the following. 
open for Dataset1 
fetch(1) for Dataset1 
fetch(2) for Dataset1 
... 
fetch(n) for Dataset1 
open for Dataset2 
fetch(1) for Dataset2 
fetch(2) for Dataset2 
... 
fetch(n) for Dataset2 
Then the entries start to interleave and it all gets very messy with open and close seemingly all out of order, which is why I concluded that there might be multiple threads processing the datasets. 
That aside, the logging I've done indicates that at the very least, all of the entries for Dataset1 are being read in a single, tight, loop. This is happening even though the Detail for List(1) contains List(2). 
I was expecting EVERYTHING in the Detail section to be rendered, which would include both the text component, AND the embedded List(2). 
Well, that's probably enough for a single append, but I felt I hadn't perhaps explained the problem clearly enough in my previous attempt. 
Hopefully someone might recognise this BIRT behaviour and be able to point me in the right direction. 
In the meantime, I'm going to try and put together a simplified version of the report to allow you to reproduce the problem...

nomadau

Hi Michael, 
 
I've put together a cut-down report, and built a sample Java data source that demonstrates the problem quite nicely. 
Can you instruct me on how to send you the report, the jar file and the example outputs? I can't see how to attach files to this forum post. 
Thanks.
 
Ahhh...just found the full editor and the option to upload. Here is the sample report.
I've also included a text file showing the output I expect to get, vs. the actual output.
 
Couldn't upload the jar file, so renamed it with a pdf suffix...

mwilliams

You'll need to pass the operationName and parameterName values through data set parameters for the inner data set to get the proper current value of the outer table. Take a look at this modified version of your design. You'll see I added a data set parameter to the second data set and two to the third data set. If you select the second list element in the report layout and go to the binding tab of the property editor, you'll see a button for "data set parameter bindings". When you click on that, you'll see how I pass the outer value through this parameter. If you go into the open script for the second data set, you'll see that I set the value of your currentOperationName variable by pulling in the value of the data set parameter. The same was done for operationName and parameterName in the third data set and list. Now, the output is as you're expecting. Hope this helps. Let me know if you have questions.

nomadau

That's brilliant thanks Michael. I can see exactly what you've done to make this work, although I don't think I would have been able to figure it out without your example. I really appreciate you taking the time to help me understand this mechanism for passing current values from parent dataset(s) to child dataset(s).

nomadau

Hmmm, I've just tried to apply this technique to my original report, without success. What I can't see from your example Michael, is where the input parameter(s) are set.
In DataSet2 you created an input parameter called operationName. I can see how you retrieve the value of this input parameter in the open method of DataSet2, but where do you set it? 
When I use this approach in my original report, I find that the value is not set when I use this.getInputParameterValue("operationName").
I feel I might be missing something from your example?
 
 
 
Found the problem.... I hadn't set the 'data set parameter bindings' as per your instructions!
 
All working fine now. Again, thanks.

mwilliams

That's where the "Data Set Parameter Binding..." button from the bindings tab of the property editor for the list comes in. If you select the embedded lists, go to the binding tab of the property editor, and click the button I mentioned, you'll see where the value gets passed through.

Edit: Oops, didn't see your edit. lol. It doesn't show those in the email notifications I get. Glad you got it working.