extracts some useful data to be used by the next steps in the report.
1.The distribution of calculators among data columns
this step constructs the distribution of calculators array which keeps track of the distribution of calculators in the dataColumns array.
For example: We have a report with 6 data columns but only 3 of them have calculators (let's say the 2nd and the 4th and the 5th)
In order to be able to retrieve the right calculator value for a given dataColumn index ( as set in the configuration of the report)
we will fill this array with
array index: 0 1 2 3 4 5
array value: NO_CALCULATOR 0 NO_CALCULATOR 1 2 NO_CALCULATOR
Next time when we have the data column index and we need the result of the calculator (in a specific row of the matrix)
we will call calculatorsDistributionInDataColumnsArray[dataColumIndex] and we will get the index of the column in the calculator matrix
this method is called only once for a report
and represents the construction step where you can define the keys and
values used inside the execute method.
Warning: this is the only place where you can add keys to the report context