Learn Java Programming - Regex Possessive Quantifiers Tutorial

There are three different groupings of quantifiers: greedy, reluctant, and possessive. This tutorial is all about possessive quantifiers. Possessive quantifiers are perhaps the most rarely used of all the quantifiers. In my Regex Greedy Quantifiers Tutorial we learned that greedy quantifiers instruct the matcher to match as many instances of its quantified token and return the largest possible string value. In my Regex Reluctant Quantifiers Tutorial we learned that reluctant quantifiers instruct the matcher to match each individual instance of a quantified token and return the smallest possible string value. Once again, the difference between possessive, reluctant, and greedy quantifiers are not always obvious. Possessive quantifiers function just like greedy quantifiers only there is just one simple rule to remember - they never backtrack. The only reason that I can possibly think of to use possessive quantifiers is to increase the speed a regex search in certain situations. With the speed of today's computers, I'm not sure it really matters unless you are running a regex on a database with millions of records. However, if you are running the regex against something like a textbox validation on website or application, I would recommend simply using a greedy quantifier. The syntax for possessive quantifiers is the same as greedy quantifiers only you will simply tack a + on to the greedy quantifier to turn in into a possessive quantifier.