Jasper Reports: How does one call a java method with a int parameter from a JasperDesign class

Question

I've used jasper without using xml (I must change this still) but I have an implementation of a JasperDesign that i make use of ... I create a JRDesignTextField with a JRDesignExpression,

I would like to setup the expression so that I can get jasper to call a method on each element within a JRBeanCollectionDataSource with a integer parameter... currently i can only call methods that returns a value and take in no arguments. The expression for this is shown below:

final JRDesignExpression exp = new JRDesignExpression(); exp.setValueClass(String.class); exp.setValueClassName(String.class.getName()); exp.addFieldChunk("column0");

Answer 1

You can use setText instead of adding chunks yourself. Jasper will parse the text, adding chunks as needed - $P{param} for parameters, $F{field} for fields, $V{var} for variable, etc. For example:

exp.setText( "$F{column0}.myMethod($V{someIntVar})" )

Answer 2

You should consider using a different data-source, other than JRBeanCollectionDataSource. The JRBeanCollectionDataSource calls getter methods for each field, which is what you want to avoid.

You can use JRMapCollectionDataSource, which is created from a collection of maps. You can call the keys of your maps as you wish, like 'column0', 'column1' (or simply '0', '1', etc.)

Another option is to directly implement the JRDataSource interface, where you can implement the getFieldValue() whichever way you like.