private boolean useNotModifiedHeader ( HttpServletRequest request , String scriptEtag ) { long modifiedHeader = - 1 ; try { modifiedHeader = request . getDateHeader ( HEADER_IF_MODIFIED ) ; if ( modifiedHeader != - 1 ) modifiedHeader -= modifiedHeader % 1000 ; } catch ( RuntimeException ex ) { } String eTag = request . getHeader ( HEADER_IF_NONE ) ; if ( modifiedHeader == - 1 ) { return scriptEtag . equals ( eTag ) ; } else if ( null == eTag ) { return modifiedHeader <= START_TIME ; } else { return scriptEtag . equals ( eTag ) && modifiedHeader <= START_TIME ; } }
Determines whether a response should get a 304 response and empty body according to etags and if - modified - since headers .