Regex Issue

[Luke Shannon]

We have this line of code:

tmp = tmp.replaceAll("\\$\\{description\\}",
(current.getDescription() == null ? NOT_AVAILABLE : current.getDescription()));

If current.getDescripton() returns a string that contains a $ characher I get the following error:

java.lang.IndexOutOfBoundsException: No group 2

How can this be avoided?

Luke

[Alan Moore]

If you're using JDK 1.5, you can use Matcher.quoteReplacement(String) to escape the special characters in the replacement string (i.e., dollar sign and backslash). Otherwise, you can do it yourself:

 tmp = tmp.replaceAll("\\$\\{description\\}",
(current.getDescription() == null ? NOT_AVAILABLE :
current.getDescription().replaceAll("[$\\\\]", "\\\\$0"));

[Luke Shannon]

Thanks Alan!

[Kai Witte]

hello,

prior to 1.5 the best way to quote a String in such a situation was to put it in \Q and \E, like that:
"\\Q{...}\\E"

Conan

[Alan Moore]

Just to clarify, Conan, what you're talking about is quoting the regex, which is the first argument to replaceAll(). It doesn't work for the second argument, the replacement string. As of JDK 1.5, you can use the Pattern.quote() method to quote the regex, and Matcher.quoteReplacement() to quote the replacement string.