Bug 173582 Run servlet should not be affected by values in document.[0000]
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
Set nullParams = getParameterValues( request, PARAM_ISNULL );
		if ( nullParams != null && nullParams.contains( name ) )
		{
			isExist = true;
		}
		return isExist;
	}
	/**
	 * If set isWorkingFolderAccessOnly as true, check the file if exist in
	 * working folder.
	 * 
	 * @param filePath
	 * @return boolean
	 */
	public static boolean isValidFilePath( String filePath )
	{
		assert filePath != null;
		if ( isWorkingFolderAccessOnly )
		{
			File docFile = new File( filePath );
			if ( !docFile.isAbsolute( ) )
				return true;
			File docFolder = new File( workingFolder );
			if ( docFolder.isAbsolute( ) )
			{
				String absolutePath = docFile.getAbsolutePath( );
				String docFolderPath = docFolder.getAbsolutePath( );
				
				if ( isWindowsPlatform( ) )
				{