RegexTokenIterator

RegexTokenIterator is a class in the Java programming language that provides an iterator over the tokens of a string that match a given regular expression pattern. It is part of the java.util.regex package and is used to split a string into tokens based on a regular expression.

The RegexTokenIterator class is constructed with a CharSequence (such as a String) and a Pattern object, which represents the regular expression pattern. The pattern is used to define the boundaries of the tokens. The iterator will return each token as a MatchResult object, which provides information about the match, including the start and end indices of the match within the original string.

The RegexTokenIterator class implements the Iterator interface, allowing it to be used in a for-each loop or with other methods that accept an Iterator. It also provides a hasNext() method to check if there are more tokens to iterate over, and a next() method to retrieve the next token.

One of the key features of RegexTokenIterator is its ability to handle overlapping matches. If the regular expression pattern allows for overlapping matches, the iterator will return each match as a separate token, even if the matches share characters. This can be useful in certain text processing tasks, such as finding all occurrences of a substring within a string.

In summary, RegexTokenIterator is a useful class for splitting a string into tokens based on a regular expression pattern. It provides an easy-to-use interface for iterating over the tokens and retrieving information about each match. Its ability to handle overlapping matches makes it a powerful tool for text processing tasks in Java.