Bug 153412 Change parameter type will cause preview fail
Description: Change parameter type will cause preview fail Steps to reproduce: 1. New a report paramter, string, text-box, default value is abc. 2. Drag the parameter to Layout and preview. 3. Change the parameter's type to integer, list-box, add a value 1 4. Preview Expected result: No errors. Actual result: The value "abc" is invalid with the type "integer".
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
IReportDocument reportDocumentInstance = ReportEngineService
				.getInstance( ).openReportDocument( this.reportDesignName,
						this.reportDocumentName );
		if ( reportDocumentInstance != null )
		{
			reportRunnable = reportDocumentInstance.getReportRunnable( );
			
			
			
			
			
			if ( IBirtConstants.SERVLET_PATH_FRAMESET.equalsIgnoreCase( request
					.getServletPath( ) ) )
			{
				this.parameterMap = reportDocumentInstance.getParameterValues( );
			}
			if ( ParameterAccessor.getParameter( request,
					ParameterAccessor.PARAM_REPORT_DOCUMENT ) != null )
				this.documentInUrl = true;
			reportDocumentInstance.close( );
		}
		
		if ( reportRunnable == null )
		{
			try
			{
				
				File file = new File( this.reportDesignName );
				if ( file.exists( ) )
				{