Bug 173389 Exception is thrown when edit the cascading parameter group[0002]
Exception is thrown when edit the cascading parameter group[0002] Build number: 2.2.0.v20070208-1000 Steps to reproduce: 1.new a sample data source and select CUSTOMERS table as data set 2.new a cascading parameter group and use the data set,select the CUSTOMERNAME ,drag the parameter to layout then preview 3.switch to data explorer ,click the parameter ,change the CUSTOMERNAME to CUSTOMERNUMBER 4.preview in layout Expected result: No exception thrown Actual result: Exception thrown Error log: see attached image
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/service/BirtViewerReportService.java
{
				IScalarParameterDefn engineParam = (IScalarParameterDefn) o;
				ParameterGroupDefinition group = null;
				ParameterDefinition param = convertScalarParameter(
						engineParam, group );
				ret.add( param );
			}
			else if ( o instanceof IParameterGroupDefn )
			{
				IParameterGroupDefn engineParam = (IParameterGroupDefn) o;
				ParameterGroupDefinition paramGroup = convertParameterGroup( engineParam );
				ret.add( paramGroup );
			}
		}
		if ( includeGroups )
			return ret;
		
		return flattenGroups( ret );
	}
	/**
	 * Flatten the results
	 * 
	 * @param params
	 */
	private static List flattenGroups( List params )
	{
		if ( params == null || params.size( ) == 0 )
			return Collections.EMPTY_LIST;
		List ret = new ArrayList( );
		for ( Iterator it = params.iterator( ); it.hasNext( ); )