Unicode-Aware Case Folding Pattern class constant ' 2 ft, 5 ft' /* This expression represents a product code*/ There has to be one \s between \d+ and ft.*/ ' 2 ft, 5 ft' /* Extra spaces won't make a difference. * Now we have to use \s for a white-space.*/ ' 2 ft, 5 ft' /* After enabling comment mode we cannot match space between \d+ and ft.*/

Examples /* By default we can use spaces as literals.*/ The embedded comments starting with # are also ignored until the end of a line. Whitespace are treated as they are not there during regex matching time. This mode enables white whitespaces and comments in the pattern. find() //matches: 'The is a one sentence' at 0-22Ĭomments and White-Spaces Mode Pattern class constant ' The First line The SecondLine' /* Using embedded flag for DOTALL.*/ ' The First line The SecondLine' /* Removing DOTALL will get us the right result in above case.*/ find() //matches: 'The First line The SecondLine' at 0-29 matcher('The First line The SecondLine'). pile('^T.*e$', Pattern.MULTILINE | Pattern.DOTALL).

That's because DOTALL makes the engine to see 'line terminators' as normal characters.*/ ' The is one sentence' /* But, using Pattern.MULTILINE with Pattern.DOTALL doesn't give desired matches for the patterns which are targeting '^' and '$'. find() //matches: 'The is one sentence' at 0-21 pile('The.*sentence', Pattern.MULTILINE | Pattern.DOTALL). Enabling MULTILINE with DOTALL doesn't effect DOTALL results*/ On the other hand, Pattern.DOTALL causes engine to see all line terminator as literal character which can be matched by a dot (.). Pattern.MULTILINE matches ^ and $ for the line terminator wherever they are. ' The is one sentence' /* Pattern.MULTILINE does the entirely different thing, i.e. Examples /* We want to match the given input string as a single line, but we cannot unless we enable DOTALL mode.*/ By default the line terminators are the only ones dot doesn't match. The dot (.) in regex expression can match them as well. When this mode is enabled, line terminators ( or or ) are treated as literal. find() //matches: 'The First line' at 0-14, 'The SecondLine' at 16-30ĭot-All (Single Line) Mode Pattern class constant matcher('The First line The SecondLine'). ' The First line The SecondLine' /* Using together*/ find() //matches: 'The First line' at 0-14, 'The SecondLine' at 15-29 matcher('The First line The SecondLine'). ' The First line The SecondLine' /* Using */ ' The First line The SecondLine' /* Using embedded flag.*/ ' The First line The SecondLine' /* Including $ at the end in the regex.*/

find() //matches: 'The First line' at 0-14 When this mode is enabled, ^ and $ will be used to match at the start and end of each line. * Turning on/off the flags in the middle*/ ' Stew Pasta Twinkies' /* Turning off the flag. ' Stew Pasta Twinkies' /* These flags can be used anywhere in the expression*/ ' Stew Pasta Twinkies' /* Using embedded flag.*/ pile('\b+\b', Pattern.CASE_INSENSITIVE). We can also embed these flags in the expression as we will see in examples below.Ĭase Insensitive Mode Pattern class constantĮxamples /* The default case sensitive matching*/ The flags parameter is a bit mask that may include any of the public static fields provided in Pattern class. We can set these flags at the construction time by using the overloaded static method compile(String regex, int flags). These flags effect the way Java regex engine matches the pattern. Java provides a set of flags to override the certain defaults.