prevent BIRT from "building" a hidden table

hi guys 
 
my report design cotains a list (using dataset1) and in this list a table (using dataset2). i want to hide the table if the list exceedes a specific number of records. 
 
my intention is to prevent generation of huge reports which might end in a out-of-memory exception. i want to stop the generation as well if it would take too much time to generate. 
 
1) i defined a global variable "limitIsExceeded" and set it to false in the report's initialize script 
2) i created a aggregated count variable in the list's binding which gives me the total number of records for dataset1 
3) "limitIsExceeded" is set properly in the list's script if the numer of records exceeds my limit 
4) on the tables visibility property i activated hide[x] and i'm using the following expression: "if ( limitIsExceeded ) { true } else { false }" 
 
if limitIsExceeded is true the table is hidden as expected. but the problem is, the table is "processed" though. i.e. the generation is not stopped at the point the table's visibility condition matches. i used the logger to print out some info so i am sure the table is not omitted and still "built". 
 
can anyone tell me what i'm doing wrong? 
 
regards 
bartek 
 
PS. i searched for solutions and found this <a class='bbc_url' href='http://www.birt-exchange.org/org/forum/index.php/topic/24253-hide-outer-tables-row-based-on-variable-set-by-sub-table/page__hl__hide__fromsearch__1'>link1</a> and this <a class='bbc_url' href='http://www.birt-exchange.org/org/forum/index.php/topic/24253-hide-outer-tables-row-based-on-variable-set-by-sub-table/page__hl__hide__fromsearch__1'>link2</a> but i did not found any hints.

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kclark

It sounds like you want to drop the table instead of hide it. If you drop the table then it's not generated. <a class='bbc_url' href='http://www.birt-exchange.org/org/devshare/designing-birt-reports/1027-drop-a-table-based-on-a-report-parameter/'>This devshare</a> has a good example that drops a table based on a report parameter.

birtslash

<blockquote class='ipsBlockquote' data-author="'kclark'" data-cid="113826" data-time="1359736765" data-date="01 February 2013 - 09:39 AM">
It sounds like you want to drop the table instead of hide it. If you drop the table then it's not generated. <a class='bbc_url' href='http://www.birt-exchange.org/org/devshare/designing-birt-reports/1027-drop-a-table-based-on-a-report-parameter/'>This devshare</a> has a good example that drops a table based on a report parameter. </blockquote>
 
it is nice idea to drop the table for what i intend to do but it seems it does not work as it should. 
 
as described before, whether the table should be hidden or not i know at the moment the first dataset is built. so i inserted a text element in the list's header and try to drop the inner table there via javascript: 
<pre class='_prettyXprint _lang-auto _linenums:0'>
if (row["aggr_count_groups"] > params["rowLimit"].value ) {
var elmTable = reportContext.getReportRunnable().designHandle.getDesignHandle().findElement("myTable");
if (elmTable != null) {
elmTable.drop();
log("table dropped");
}
}
</pre>
 
i removed the "[ ]hide element" option on the table to see if the table has been dropped. i can see "table dropped" message in the birt log file but the table is still displayed. 
i'm pretty clueless about it. any help? 
 
bartek

birtslash

eventually the dropping of the table works only in the report's beforeFactory() event. but my problem is, at this point the datasets are not 'built' yet, so i cannot decide at this point whether i want to drop the table or not. 
 
the question still remains, how can i drop the table after the data is fetched from the database? 
 
i tried to drop the entire list's detail section (where the table resides) by using the onCreate() event in an element in the lists header: 
<pre class='_prettyXprint _lang-auto _linenums:0'>reportContext.getDesignHandle().findElement("list_EP_data").getDetail().get(0).drop();</pre>
but this does not work as well. it seems that if i try to drop the table or the table's container (the list's detail section) at any other place after the report's beforeFactory event, it just will not work, the table is always displayed. 
 
any ideas why it does not work? or any pointers on that, how to hide the table so it's contents are not processed?

CBR

you are right: The code provided in the dev share only works in the beforeFactory. At any other place it is already too late to drop an element in the report (the drop is silently ignored).
I m trying to look for some other solution (not sure if it exists)

Clement Wong

Bartek, 
 
<a class='bbc_url' href='http://www.birt-exchange.org/org/devshare/designing-birt-reports/1542-data-engine-api-to-check-data-set-values/'>This DevShare @ http://www.birt-exchange.org/org/devshare/designing-birt-reports/1542-data-engine-api-to-check-data-set-values/</a> will give you a baseline to solve your requirement. 
 
I've attached a variation on the above that is similar to what you are looking for. One DataSet query is the actual query to get the data. The other DataSet query is to count the number of records for that same query. If there are too many records, then it will drop the detail table and display an error message. Otherwise, it will display the records, and drop the error message. 
 
In the attached report, the parameter, rowLimit, is the internal threshold. Use 3 or 30 to see the user error message that the limit has been exceeded. Otherwise, you can accept the default to see the entire report. 
 
I ran and tested the attached sample design in both Actuate BIRT Designer Professional 11 SP4 Fix1 and in Open Source BIRT Designer 3.7.2.

birtslash

<blockquote class='ipsBlockquote' data-author="'Clement Wong'" data-cid="114176" data-time="1360796590" data-date="13 February 2013 - 04:03 PM">
Bartek, 
 
<a class='bbc_url' href='http://www.birt-exchange.org/org/devshare/designing-birt-reports/1542-data-engine-api-to-check-data-set-values/'>This DevShare @ http://www.birt-exchange.org/org/devshare/designing-birt-reports/1542-data-engine-api-to-check-data-set-values/</a> will give you a baseline to solve your requirement. 
 
I've attached a variation on the above that is similar to what you are looking for. One DataSet query is the actual query to get the data. The other DataSet query is to count the number of records for that same query. If there are too many records, then it will drop the detail table and display an error message. Otherwise, it will display the records, and drop the error message. 
 
In the attached report, the parameter, rowLimit, is the internal threshold. Use 3 or 30 to see the user error message that the limit has been exceeded. Otherwise, you can accept the default to see the entire report. 
 
I ran and tested the attached sample design in both Actuate BIRT Designer Professional 11 SP4 Fix1 and in Open Source BIRT Designer 3.7.2. </blockquote>
 
thanks a lot clement. it is pretty well explained here: <a class='bbc_url' href='http://www.birt-exchange.org/org/forum/index.php/topic/24303-unable-to-drop-report-elements-from-within-another-report-elements/'>unable to drop report elements...</a>. i will give it a try and give you a feedback=)

birtslash

<blockquote class='ipsBlockquote' data-author="'birtslash'" data-cid="114183" data-time="1360835024" data-date="14 February 2013 - 02:43 AM">
thanks a lot clement. it is pretty well explained here: <a class='bbc_url' href='http://www.birt-exchange.org/org/forum/index.php/topic/24303-unable-to-drop-report-elements-from-within-another-report-elements/'>unable to drop report elements...</a>. i will give it a try and give you a feedback=) </blockquote>
 
... works like a charm^^ thanks for the solution!