I have the following method to check allowed characters:
private boolean checkIfAllCharsAreValid(String test) {
boolean valid = false;
if (test.matches("^[a-zA-Z0-9,.;:-_'\\s]+$")) {
valid = true;
}
return valid;
}
but if test has the character - in it the match return false. Do i have to escape the -?
Inside [...] the - symbol is treated specially. (You use it yourself in this special purpose in the beginning of your expression where you have a-z.)
You need to escape the - character
[a-zA-Z0-9,.;:\-_'\s]
^
or put it last (or first) in the [...] expression like
[a-zA-Z0-9,.;:_'\s-]
^
Some further notes:
Technically speaking all characters are valid in the empty string, so I would change from + to * in your expression.
String.matches checks the full string, so the ^ and $ are redundant.
Your entire method could be wirtten as
return test.matches("[a-zA-Z0-9,.;:_'\\s-]*");
a-zA-Z0-9_ as part of the character class, wouldn't it simplify things to use \w instead?, i.e. "[\\w,.;:'\\s-]*"You can put the - at the start of the character group so that it is not interpreted as a character range.
A - in a character class surrounded on both sides is a regex meta character to denote range.
To list a literal - in a char class you escape the - in the char class:
if (test.matches("^[a-zA-Z0-9,.;:\\-_'\\s]+$"))
^^^
or place the - at the end of char class:
if (test.matches("^[a-zA-Z0-9,.;:_'\\s-]+$"))
^
or place the - at the beginning of char class:
if (test.matches("^[-a-zA-Z0-9,.;:_'\\s]+$"))
^
