RegEx Rules - NEW! 🚀
Java Regular Expressions, also known as RegEx, are sequences of characters that form a search pattern. A RegEx can be used to perform text searches as it defines a set of strings, usually united for a given purpose, i.e., to describe what you are searching for.
In the following paragraphs, we have included essential RegEx rules that you might find useful when compiling your RegEx.
For a complete RegEx syntax, refer to the class Pattern of Oracle documentation available at this link: https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html
Character Classes
| [abc] | Matches a or b, or c. |
| [^abc] | Negation, matches everything except a or b, or c. |
| [a-c] | Range, matches a or b, or c. |
| [a-c[f-h]] | Union, matches a, b, c, f, g, h. |
| [a-c&&[b-c]] | Intersection, matches b or c. |
| [a-c&&[^b-c]] | Subtraction, matches a. |
Predefined Character Classes
| . | Any character. |
| \d | A digit: [0-9]. |
| \D | A non-digit: [^0-9]. |
| \s | A whitespace character: [\t\n\xOB\f\r]. |
| \S | A non-whitespace character: [^\s]. |
| \w | A word character: [a-zA-Z_0-9]. |
| \W | A non-word character: [^\w]. |
Boundary Matches
| ^ | The beginning of a line. |
| $ | The end of a line. |
| \b | A word boundary. |
| \B | A non-word boundary. |
| \A | The beginnng of the input. |
| \G | The end of the previous match. |
| \Z | The end of the input but for the final terminator, if any. |
| \z | The end of the input. |
Pattern Flags
| Pattern.CASE_INSENSITIVE | Enables case-insensitive matching. |
| Pattern.COMMENTS | Whitespace and comments starting with # are ignored until the end of a line. |
| Pattern.MULTILINE | One expression can match multiple lines. |
| Pattern.UNIX_LINES | Only the '\n' line terminator is recognized in the behavior of ., ^, and $. |
Useful Java Classes and Methods
PATTERN
A pattern is a compiler representation of a regular expression.
| Pattern compile(String regex) | Compiles the given regular expression into a pattern. |
| Pattern compile(String regex, int flags) | Compiles the given regular expression into a pattern with the given flags. |
| boolean matches(String regex) | Tells whether or not this string matches the given regular expression. |
| String[] split(CharSequence input) | Splits the given input sequence around matches of this pattern. |
| String quote(String s) | Returns a literal pattern String for the specified String. |
| Predicate<String> asPredicate() | Creates a predicate which can be used to match a string. |
MATCHER
An engine that performs match operations on a character sequence by interpreting a pattern.
| boolean matches() | Attempts to match the entire region against the pattern. |
| boolean find() | Attempts to find the next subsequence of the input sequence that matches the pattern. |
| int start() | Returns the start index of the previous match. |
| int end() | Returns the offset after the last character matched. |
Quantifiers
| Greedy | Matches the longest matching group. |
| Reluctant | Matches the shortest group. |
| Possessive | Longest match or bust (no backoff). |
| Greedy | Reluctant | Possessive | Description |
| X? | X?? | X?+ | X, once or not at all. |
| X* | X*? | X*+ | X, zero or more times. |
| X+ | X+? | X++ | X, one or more times. |
| X{n} | X{n}? | X{n}+ | X, exactly n times. |
| X{n,} | X{n,}? | X{n,}+ | X, at least n times. |
| X{n,m} | X{n,m}? | X{n,m}+ | X, at least n but not more than m times. |
Groups & Backreferences
A group is a captured subsequence of characters that may be used later in the expression with a backreference.
| (...) | Defines a group. |
| \N | Refers to a matched group. |
| (\d\d) | A group of two digits. |
| (\d\d)/\1 | Two digits repeated twice. \1 Refers to the matched group. |
Logical Operations
| XY | X then Y. |
| X|Y | X or Y. |
🚀 Date placeholders
The RegEx field in the File Event Listener supports specific date placeholders that will be dynamically replaced at runtime.
Syntax
${date:<number of days before or after today's date>,format}
today's dateis the offset value, and it is0. You can go back with<-n>, e.g.,${date:-4}or forward with<+n>, e.g.,${date:+1}.
For example, if the offset date is 2025-04-10 and you enter${date:-1}, the resulting date would be 2025-04-09.formatis the date and time format, which can be specified using the standard notation available at this link: DateTimeFormatter (Java Platform SE 8).
If noformatis specified, the standard ISO8601 format will be used.
These placeholders are supported:
- TODAY ISO format
Format:${date}or${date:0}
Example:^cme.${date}.s.pa2.zip$ - TODAY
Format:${date:0, format}
Example:^ME${date: 0, yyMMdd}.zip$ - YESTERDAY ISO format
Format:${date:-1}
Example:^IRM2.0_IM_ICUS_${date:-1}.zip - YESTERDAY
Format:${date:-1, format}
Example:^OPT${date:-1, MMdd}F.SP6.zip$ - TOMORROW
Format:${date:+1, format}
Example:^OPT${date:+1, MMdd}F.SP6.zip$ - Custom PAST DAY
A custom number of days in the past from today's date:${date:-3}
Example:^OPT${date:-3, yyyyMMdd}F.SP6.zip$ - Custom FUTURE DAY
A custom number of days in the future from today's date:${date:+2}
Example:^OPT${date:+2, yyyyMMdd}F.SP6.zip$
Updated 6 days ago