Bug 176681 Issue about creating context-parameter path in read-only path[0601]
Description: Issue about creating context-parameter path in read-only path Build number:2.2.0.v20070308 Steps to reproduce: 1. Deploy birt. 2. Set BIRT_VIEWER_DOCUMENT_FOLDER/BIRT_VIEWER_IMAGE_DIR/.. to a read-only path. 3. Preview report. Expected result: Because the path is read-only, folders should be created in ${java.io.tmpdir} Actual result: No folders are created in ${java.io.tmpdir} and reports cannot be previewed in frameset mode.
viewer/org.eclipse.birt.report.viewer/birt/WEB-INF/classes/org/eclipse/birt/report/utility/ParameterAccessor.java
return paramName.replaceFirst( PREFIX_DISPLAY_TEXT, "" ); 
		}
		return null;
	}
	/**
	 * Generates a file name for the pdf output.
	 * 
	 * @param request
	 * @return the file name
	 */
	public static String generateFileName( HttpServletRequest request )
	{
		String defaultName = "BIRTReport"; 
		String fileName = defaultName;
		BaseAttributeBean attrBean = (BaseAttributeBean) request
				.getAttribute( IBirtConstants.ATTRIBUTE_BEAN );
		if ( attrBean == null )
			return fileName + ".pdf"; 
		String baseName = attrBean.getReportDesignName( );
		if ( baseName == null || baseName.length( ) == 0 )
			baseName = attrBean.getReportDocumentName( );
		assert baseName != null && baseName.length( ) > 0;
		int index = baseName.lastIndexOf( '/' );
		if ( index == -1 )
			index = baseName.lastIndexOf( '\\' );
		
		
		if ( index != -1 )
		{
			baseName = baseName.substring( index + 1 );