string - contains() method without prefix and suffix in Java -

i'm stuck on (simple, think) string validation. use following method text edittext can have 420 chars , must contain specific word (whatever place):

if(edittext.gettext().tostring().tolowercase().contains(stringtohave)) { } // stringtohave = specific string   

however, want improve condition. example, have this:

string = "this not metastackoverflow question";  string b = "stackoverflow";   

and want know if a contains b regardless case sensitive, then, follows:

if(a.tolowercase().contains(b)) { }   

this condition true because indeed a contains stackoverflow. however, a doesn't contain exactly b, there prefix meta. , not same word.. tried find way on , on other java websites without result.

how can improve contains() method find exact string without prefix or suffix? should use method (as containsonly(), tried seems undefined string, it's check if contains numeric/alphabetic/etc. chars)?

edit:

add "two spaces" verification attractive , ingenious. however, if specific text @ end of sentence , add . not work, isn't it?

a = "this great. on stackoverflow." // false because have "." 

you can use regex here. matcher class has find() method, searches pattern in string. work:

matcher matcher = pattern.compile("(?i)\\b" + pattern.quote(b) + "\\b").matcher(a); if (matcher.find()) {     // contains } 

(?i) case-insensitive embedded flag. pattern.quote() used escape regex meta-characters if in search string.