java - regular expression retrieve a portion of a string that not contain a string -

i have strings following:

it.mycompany.db.beans.str1.pd_t_class it.mycompany.db.beans.join.pd_t_class it.mycompany.db.beans.str2.pd_t_class_1 it.mycompany.db.beans.join.pd_t_class_1 pd_t_class myvar = new pd_t_class(); myvar.setpd_t_class(something); 

and want select "pd_" part substitute "" (the void string) inf entire line not contain string ".join."

what want achieve is:

it.mycompany.db.beans.str1.t_class it.mycompany.db.beans.join.pd_t_class it.mycompany.db.beans.str2.t_class_1 it.mycompany.db.beans.join.pd_t_class_1 t_class myvar = new t_class(); myvar.sett_class(something); 

the substitution not problem since i'm using eclipse search tool , hit replace show me right result.

i have tried:

^((?!\.join\.).)*(pd_)*$ // whole string selected  ^((?!\.join\.).)*(\bpd_\b)*$ // whole string selected  

i start getting frustrated since i've searched bit around (the ^((?!join bla bla come searches)

can me?

you may use following regex:

(?m)(?:\g(?!\a)|^(?!.*\.join\.))(.*?)pd_ 

and replace with

$1 

see regex demo

details:

• (?m) - pattern.multiline inline modifier flag force ^ match beginning of line rather whole string
• (?:\g(?!\a)|^(?!.*\.join\.)) - either of 2 alternatives:
  • \g(?!\a) - end of previous successful match
  • | - or
  • ^(?!.*\.join\.) - start of line has no .join. text in (as (?!.*\.join\.) negative lookahead fail match if matches 0+ chars other line break chars (.*) , .join.)
• (.*?) - capturing group #1 (referred $1 backreference in replacement pattern): 0+ chars other line breaks, few possible, first occurrence of ...
• pd_ - literal pd_

the replacement $1 backreference first capturing group restore text matched before pd_s.