Bug 207250 Check blank value for datetime type parameter from url.[0002][0705]
Description: Check blank value for datetime type parameter from url. Build number:2.3.0.v20071023 Steps to reproduce: 1. New a datetime parameter mydt,listbox, tick off isRequired. 2. Preview in external browser and add "&dt=" in url, press enter. Expected result: Error message to indicate blank value isn't allowed for this parameter. Actual result: No error message and blank value is accepted. I tried to new a jsp and use <birt:paramDef> to pass the blank value and the blank value is accepted,too. Error log:n/a
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/context/ViewerAttributeBean.java
}
		}
		return paramName;
	}
	/**
	 * Returns the report design handle
	 * 
	 * @param request
	 * @throws Exception
	 * @return Report Design Handle
	 */
	protected IViewerReportDesignHandle getDesignHandle(
			HttpServletRequest request ) throws Exception
	{
		IViewerReportDesignHandle design = null;
		IReportRunnable reportRunnable = null;
		IReportDocument reportDocumentInstance = null;
		boolean isDocumentExist = ParameterAccessor.isReportParameterExist(
				request, ParameterAccessor.PARAM_REPORT_DOCUMENT );
		boolean isReportExist = ParameterAccessor.isReportParameterExist(
				request, ParameterAccessor.PARAM_REPORT );
		
		if ( isDocumentExist && !isReportExist )
		{
			
			boolean isValidDocument = ParameterAccessor
					.isValidFilePath( ParameterAccessor.getParameter( request,
							ParameterAccessor.PARAM_REPORT_DOCUMENT ) );
			if ( isValidDocument )
			{