Checking if all characters of a string is uppercase except special symbols

Question

It's my first time to use the Pattern class of Java because I want to check a string if it is in uppercase. Special symbols like "." and "," should be treated as Uppercase. Here are the expected results:

"test,." should return false //because it has a lowercase character
"TEST,." should return true //because all are uppercase and the special characters
"test" should return false //because it has a lowercase character
"TEST" should return true //because all are uppercase
"teST" should return false //because it has a lowercase character

I tried to use the StringUtils of apache but it doesn't work this way..

Answer 1

You can check:

if (str.toUpperCase().equals(str)) {..}

Answer 2

Just search for [a-z] then return false if it's found:

if (str.matches(".*[a-z].*")) { 
    // Negative match (false)
}

Alternatively, search for ^[^a-z]*$ (not sure on Java regex syntax, but basically whole string is not lowercase characters):

if (str.matches("[^a-z]*")) { 
    // Positive match (true)
}

Answer 3

You could iterate through the chars. It has the advantage that you can customize the matching as you wish.

boolean ok = true;
for(char c : yourString.toCharArray()) {
    if(Character.isLetter(c) && !Character.isUpperCase(c)) {
        ok = false;
        break;
    }
}
// ok contains your return value