Passing Customized Variables to User Data Source at Runtime

You can pass customized variables to a user data source (UDS) at runtime, by implementing the jet.datasource.JRUserServerInfoDataSource interface and adding customized variables in the session or URL. This topic describes how to pass customized variables to UDS.

Implement the jet.datasource.JRUserServerInfoDataSource interface so that your UDS can receive customized variables.
Read customized variables in UDS. Server collects customized variables from the session or URL and stores them in a java.util.Properties in the jet.server.api.ServerInfo interface. You can then get the java.util.Properties to obtain the customized variables, through ServerInfo.getTaskProperties().
```
Properties props = getServerInfo().getTaskProperties();
String var1 = props.getProperty("UDP$Var1");
String var2 = props.getProperty("UDP$Var2");
```
You can use the following three ways to set customized variables to UDS, with the priority from highest to lowest:
- Set customized variables using the Report session variable feature. Use a java.util.Properties to collect all customized variables and set the java.util.Properties by HttpSession.setAttribute to the HttpSession with the key JReport_running_parameter. See the following example:
```
Properties ssnVars = new Properties();
ssnVars.setProperty("Var1", "a");
ssnVars.setProperty("Var2", "b");

HttpSession httpsession = request.getSession();
httpsession.setAttribute("JReport_running_parameter", ssnVars);
```
- Set customized variables in the HttpSession, by setting attributes that start with UDP$.
```
HttpSession httpsession = request.getSession();
httpsession.setAttribute("UDP$Var1", "a");
httpsession.setAttribute("UDP$Var2", "b");
```
- Set customized variables in the URL of running a report, by setting parameters that start with UDP$.
```
http://localhost:8888/jinfonet/runReport.jsp?jrs.report=%2freport1.wls&jrs.catalog=%2fSampleReports.cat&jrs.result_type=8&UDP$Var1=a&UDP$Var2=b
```

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