Managing Parameters

Parameters are the best communication channel between the report engine and the execution environment (your application). Parameters are used inside expressions and queries. By setting parameters, you can change the behavior of an expression or return different fields from a query.

A parameter can have a default value defined by means of the default expression property. This expression is evaluated by JasperReports only when a value for the parameter has not been provided by the user at run time.

Managing Parameters

You can manage parameters using outline view or on the Parameters tab of the Dataset and Query dialog.

Parameters in Outline View

Parameters in Dataset and Query Dialog

Managing Parameters Using Outline View

To delete a parameter, right-click on it and select Delete. Parameters with light gray names are created by the system and can not be deleted or edited.
To view or edit parameter properties, right-click on the parameter and choose Show Properties. To view or edit advanced properties, click the Advanced tab in Properties view, select Properties, and click .
To sort the list of parameters alphabetically in the Outline view, right-click the Parameters node and select Sort Alphabetically. This does not affect the order of the parameters in the report.
To toggle show/hide system parameters, right-click the Parameters node and select Hide Default Parameters.
To add a parameter, right-click the Parameters node and choose Create Parameter.
To add a parameter set, right-click the Parameters node and choose Create Parameter Set.
To change the order of parameters on the menu, select the parameter you want to move and drag it up and down.

Managing Parameters Using the Parameters tab in the Dataset and Query Dialog

To toggle show/hide system parameters, click .
To toggle show/hide parameter properties, click .
To add a parameter, click Add on the Parameters tab.
To delete a parameter, select it in the Parameters tab and click Delete. The Delete button is grayed out for system parameters, which cannot be deleted or edited.
To add a parameter property, make sure parameter properties are displayed, select the Parameter, and click Add Property.
To view or edit parameter properties, double-click the parameter, or select it in the Parameters tab and click Edit (grayed out for system parameters). A Parameter dialog opens. To view or edit advanced properties, click next to Properties in the Parameter dialog.

Also see Using the Dataset and Query Dialog.

Working with Parameter Properties

Parameters - Properties

Basic Parameter Properties

Parameters have the following properties on the Object tab in outline view or in the Parameters dialog:

Name – Name of the parameter.
Class – Class type of the parameter.
Description – A string describing the parameter. This is shown as the parameter tooltip in the Input Parameters pane in preview.
Is for Prompting – Enable this to have Jaspersoft Studio prompt for the parameter when you preview the report. If you have this selected and are publishing the report to the server, you will need to create input controls on the server. May also be passed to an external application.
Default Value Expression – Pre-defined value for the parameter. This value is used if no value is provided for the parameter from the application that executes the report. The type of value must match the type declared in the Class field.

You may legally define another parameter as the value of Default Value Expression, but this method requires careful report design. Jaspersoft Studio parses parameters in the same order in which they are declared, so a default value parameter must be declared before the current parameter.

Evaluation Time – Use this to specify the evaluation time for the parameter:
     Early – Evaluate the parameter default value expression before the data adapter.
     Late – Evaluate the parameter default value expression before the data adapter.

Advanced Parameter Properties

On the Advanced tab, you can use the Properties field to specify pairs of type name/value as properties for each parameter. This is a way to add extra information to the parameter for use by external applications. For example, you can use properties to include the description of the parameter in different languages or to add instructions about the format of the input prompt.

Advanced properties for a parameter

Selecting Properties, and clicking brings up the Properties dialog box. For example, if you have a web services type data adapter, you see the following properties.

Advanced Properties for Parameters

 

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