I want to match the following: a zero length line, with the match continuing across lines of non-zero length until a particular string is matched in a line. Eg: the match starts with a zero length line and continues until STOP is reached:
Some random text I don't care about
The match starts at the beginning of this line
The match continues across this line
The match stops here STOP more
text I don't care about
Any suggestions?
Thanks
This should do it:
(?ms)^[ \t]*+$\s*+((?:(?!STOP).)*+)
A little demo:
import java.util.regex.Matcher;
import java.util.regex.Pattern;
public class Main {
public static void main(String[] args) {
String text = "Some random text I don't care about" + "\n" +
"" + "\n" +
"The match starts at the beginning of this line" + "\n" +
"The match continues across this line" + "\n" +
"The match stops here STOP more" + "\n" +
"don't care about" + "\n" +
"" + "\n" +
"" + "\n" +
"" + "\n" +
"foo" + "\n" +
"barSTOP" + "\n" +
"text I don't care about";
Matcher m = Pattern.compile("(?ms)^[ \t]*+$\\s*+(?:(?!STOP).)*+").matcher(text);
while(m.find()) {
System.out.println("match ->"+m.group()+"<-");
}
}
}
which will output:
match ->
The match starts at the beginning of this line
The match continues across this line
The match stops here <-
match ->
foo
bar<-
A small explanation:
(?ms) # enable mutli-line and dot-all
^[ \t]*+$ # match and empty line
\s*+ # match the line break
( # start group 1
(?:(?!STOP).) # if the string 'STOP' cannot be seen, match any character
*+ # match the previous zero or more times (possessively)
) # stop group 1
Making sure you set the "match multi-line" flag, the expression is "\\\\n(\\\\n.*STOP)"
. The first (and only) match group yields your result. On DOS and windows systems use "\\\\r\\\\n"
in place of "\\\\n"
.
(?ms)^$(.+)STOP
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