How to specify multiple file suffices with regex

[Jack Bush]

Hi All,

I would like to find out the correct regex to pickup multiple file suffices when looking for files that ends with “.txt”, “.xml” and “pdf” such as the following example:

( i ) if (currentFile.isFile() && currentFile.getName().endsWith(".(txt|xml|pdf).*$"))
( ii ) if (currentFile.isFile() && currentFile.getName().endsWith(".(txt|xml|pdf).*"))
( iii ) if (currentFile.isFile() && currentFile.getName().endsWith(".($:(txt|xml|pdf))"))
( iv ) if (currentFile.isFile() && currentFile.getName().endsWith(".($:(txt|xml|pdf)).*$"))
( v ) if (currentFile.isFile() && (currentFile.getName().endsWith(".txt") || currentFile.getName().endsWith(".xml")) || currentFile.getName().endsWith(".pdf")) 

Only the last ( v ) statement has worked by separate each suffix with its own endsWith() which means that there is something wrong with all my regex between ( i ) – ( iv ) .

Any idea on what is wrong with them?

Thanks in advance,

Jack

[Rob Spoor]

You can't use endsWith with regular expressions. Use matches instead:

if (currentFile.isFile() && currentFile.getName().matches("(?i).*\\.(txt|xml|pdf)$"))

The (?i) makes the matching case insensitive. Leave it out to have case sensitive matching. You need the leading .* because matches uses exact matching, not substring matching.

[Campbell Ritchie]

Find lastIndexOf(".").

Add 1.

Substring from that position

??

[Winston Gutkowski]

Campbell Ritchie wrote:

Find lastIndexOf(".").

Add 1.

Substring from that position

??

You still have the case-sensitivity problem that Rob mentioned.

Rob Spoor wrote:...&& currentFile.getName().matches("(?i).*\\.(txt|xml|pdf)$"))

Rob, do you know how that (?i) gets implemented? I can't see anything in the docs that says whether it's Unicode-aware or not.

Winston

[Rob Spoor]

For Unicode support there's two other flags: (?u) and (?U). See java.util.regex.Pattern, and more specifically UNICODE_CASE and UNICODE_CHARACTER_CLASS, for more information.

[Winston Gutkowski]

Rob Spoor wrote:For Unicode support there's two other flags: (?u) and (?U). See java.util.regex.Pattern, and more specifically UNICODE_CASE and UNICODE_CHARACTER_CLASS, for more information.

Ah, thanks a lot. I was looking in the wrong place.

Winston

[Rob Spoor]

You're welcome.

[Jack Bush]

Hi Rob,

Your initial suggestion below has worked like a gem:

if (currentFile.isFile() && currentFile.getName().matches("(?i).*\\.(txt|err|ok)$"))

On the other hand, I don't understand what Campbell Ritchie's comment below mean:

Find lastIndexOf(".").
Add 1.
Substring from that position

Could someone elaborate a bit further on this?

Thanks again,

Jack

[Rob Spoor]

currentFile.getName().lastIndexOf('.') would return the index of the last dot, or -1 if there are no dots in the name. If you then add 1, you get the index of the first character after the last dot, or 0. Calling substring from that index on would give you either the extension, or the entire name.

[Jack Bush]

Crystal clear now Rob,

Don't know what to do without you.

Cheers,

Jack

[Rob Spoor]

Get your answers from any other member around here?

[Campbell Ritchie]

No, they didn’t