Steps to a Match

Here are the steps to match a regular expression with a target string:

1. Create a Pattern object that contains the regular expression:
   • Use the static method compile(String regex) of the Pattern class.
2. Create a Matcher object linked to the target string:
   • Use the matcher(String target) method of the Pattern object.
   • The Matcher object now encapsulates the regular expression and the target string.
3. Invoke any of several methods of the Matcher object to perform matching.
   • matches() asks if the target string completely matches the regular expression.
   • Other methods do other useful things.

Once a Pattern object has been created, it can be used repeatedly to create Matcher objects for a succession of strings. For example, to search a text file, you could create a Pattern object for the pattern, then use it to create a Matcher object for each line of the file.