Efficient way to divide a String

I have a String which can be very long so I want to split it in an array of Strings so in each position the string's length should be lower than a specified number. The split can only be done in a white space or after a punctuation symbol, because I need that each fragments makes sense when it is read. It is something like a word processor so when the word doesn't fit in the current line it goes to the next line.

I had thought in splitting the given String in the white spaces or punctuation symbols with a regular expression and the joining them controlling the length of the StringBuilder, but I think splitting in all the words and then joining them may not be very efficient.

What would be the most efficient way to perform this? I开发者_开发知识库s there any library which could help in this job?

Thank you very much.

Here is something you can try:

Let's say you have to split in strings that are at most n characters long.

• Start a position 0. Move the cursor n characters forwards.
• Move the cursor 1 character backwards until you find a character on which on can split.
• Split the string, store the first part, and reiterate on the second part.

I think this might be more efficient than splitting then joining your strings.

Apache commons might help with this.

http://commons.apache.org/lang/api-2.5/index.html

See WordUtils static function static String wrap(String str, int wrapLength) - Wraps a single line of text, identifying words by ' '.

Its also open source, so if you need something more specific just look at the source...

I'd go with the simplest approach I can think of and worry of possible efficiency or performance issues later if they really are an issue.