@ Override public int doStartTag ( ) throws JspException { // Sanity check if ( context != null && ( ! context . startsWith ( "/" ) || ! url . startsWith ( "/" ) ) ) { throw new JspTagException ( Resources . getMessage ( "IMPORT_BAD_RELATIVE" ) ) ; } // reset parameter-related state urlWithParams = null ; params = new ParamSupport . ParamManager ( ) ; // check the URL if ( url == null || url . equals ( "" ) ) { throw new NullAttributeException ( "import" , "url" ) ; } // Record whether our URL is absolute or relative isAbsoluteUrl = UrlUtil . isAbsoluteUrl ( url ) ; try { // If we need to expose a Reader, we've got to do it right away if ( varReader != null ) { r = acquireReader ( ) ; pageContext . setAttribute ( varReader , r ) ; } } catch ( IOException ex ) { throw new JspTagException ( ex . toString ( ) , ex ) ; } return EVAL_BODY_INCLUDE ; }
determines what kind of import and variable exposure to perform