Regular expressions simplify pattern-matching code - 17

After creating a Pattern object, you commonly obtain a Matcher object from Pattern by calling Pattern's public matcher(CharSequence text) method. That method requires a single text object argument, whose class implements the CharSequence interface. The obtained matcher scans the characters in the text object during a pattern match operation. Example: Pattern p = Pattern.compile ("[^aeiouy]"); Matcher m = p.matcher ("This is a test."); obtains a matcher to match nonvowel characters in This is a test..
Creating Pattern and Matcher objects is bothersome when you wish to quickly check if a pattern completely matches a text sequence. Fortunately, Pattern offers a convenience method to help you accomplish that task: public static boolean matches(String regex, CharSequence text). That static method returns a Boolean true value if and only if the entire text character sequence matches regex's pattern. Example: System.out.println (Pattern.matches ("[a-z[\\s]]*", "all lowercase letters and whitespace only")); returns a Boolean true value, indicating only whitespace characters and lowercase letters appear in all lowercase letters and whitespace only.