how to deal with complex branching in iReport or Jasper

I need to fill a field in a report based on the end result of a complex branching statement. How do I do this in iReport? The report needs to show a different string depending on what is in different fields in the database. Do I make a really complex SQL statement? Do I use 开发者_JAVA技巧variables?

So, for instance,

If field x=1 IF y=1 IF z=1 Field should read A

If x=1 IF y=1 IF z=2 Field should read B

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You could do something similar to the following:

( $F{staff_type} == null ? new String("") :
( $F{staff_type}.equalsIgnoreCase("Permanent") ? new String("1") :
( $F{staff_type}.equalsIgnoreCase("Non-permanent") ? new String("2") : new String("")
)))

Basically, you need to use nested condition expressions.

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in the textfieldexpression write an expression like this

(($F{PAYMENTMODE}.equals("CS")) ? "Cash":($F{PAYMENTMODE}.equals("CQ"))? "Cheque":"Bank")e

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I think the easiest way to do this would be to have the field(s) filled by a parameter passed from the backing bean. The jdbc connection is created in the bean and passed to the report, it should be relatively easy to access the field or fields you need and run the data through a method which determines the branching outcome. Assign the outcome to the parameter and pass it to the report in the jasperParameter variable of JasperFillManager.fillReport(file, parameters, jdbcConnection).

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Usually, I handle all the programming logic before passing the data to the Jasper Report Engine, but in some cases, post-processing or post-checking is required. If it is that scenario and If I had MANY cases (strings) to check, I would code a 'Jasper Report Scriptlet' and handle that logic there (so that the code/report is readable and maintainable and also for code reuse). If it is just 2 or 3 strings to check, I would use the 'Ternary' operator.

If you want to use report scriptlet, create a scriptlet class (or use an existing one), code a method to handle this logic (Ex: 'checkString' method) and put $P{REPORT_SCRIPTLET}.checkString(someString) in the TextField's expression.