[WW-3698] jasperreports plugin's ValueStackDataSource converts field values in ValueStackDataSource even when it's not wanted

• Type: Bug
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 2.2.3.1
• Fix Version/s: 2.3.20
• Component/s: Plugin - JasperReports
• Labels: patch

Environment

Tomcat 7 application server, Jasperreports 4.1.1

• Flags: Patch
• Assignee: Lukasz Lenart
• Reporter: Dario Tortola
• Created: 04/Nov/11 13:44
• Updated: 28/Apr/17 10:10
• Resolved: 29/Jul/14 08:06

Description

Report A with Subreport B
Subreport B's datasource is a java.util.List field of Report A's datasource's elements
org.apache.struts2.views.jasperreports.ValueStackDataSource.getFieldValue, after locating the value, if org.apache.struts2.util.MakeIterator.isIterable(value) instead of value a new ValueStackDataSource over value is returned.
Since ValueStackDataSource is not a java.util.List, a javax.servlet.ServletException is thrown when the returned ValueStackDataSource fails to be cast to List

To avoid such unwanted conversion it's enough to change this code on ValueStackDataSource.getFieldValue

if (MakeIterator.isIterable(value)) {
   return new ValueStackDataSource(this.valueStack, expression);
} else {
   return value;
}

replace (MakeIterator.isIterable(value)) with (!field.getValueClass().isInstance(value) && MakeIterator.isIterable(value)) for the new ValueStackDataSource to be returned only if the value is not already what the field asks for

Issue Links

• breaks: WW-4064 WW-3698 cause ClassCastException
• is duplicated by: WW-4633 ClassCastException while generating report using Struts 2.3.28 and jasperreports 4.5.1
• links to: GitHub Pull Request #71