iReport Ultimate Guide - Nimsoft Library

Data Sources and Query ExecutersIf the method hasQueryDesigner returns true, the Query designer button will be enabled. When it is clicked, iReport callsthe method designQuery, passing as parameters the currently selected instance of IReportConnection, the query string toedit (which can be blank), and a reference to the Report query dialog box (which can be null). The method must return a stringcontaining the new query, or null if the operation was canceled by the user.Sample implementations of fields providers are available in the iReport source code, in the packagecom.jaspersoft.ireport.designer.data.fieldsproviders.The query executer mechanism and the integration with the fields providers open the door to making an infinite number ofimplementations and languages available for UR. Using this feature, it’s easy to create support for any custom querylanguage.221