Regular expression for alphanumeric characters containing space ,"_" and "-"

1. First word should contain only [0-9a-zA-Z]
2. Second word can contain any of these characters[0-9a-zA-Z],space,"_" and "-".But same characters(space,"_" and "-") cannot be consicutive.For examples "__","--"," ","_-" are invalid.But "- _" is valid.
3.
i) Hello world_-(invalid)
ii) Hello world_ -(valid)
iii) Hello world--(invalid)
iv) Hello world- -(valid)
v) Hello world_ _(valid)
vi) Hello world(invalid) - 2 spaces

Can you show your regexp?

Quote:

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Originally Posted by Petr

Can you show your regexp?

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Code:

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        public static boolean isAlphaNumericWithSpace(String input) {       
        return isAlphaNumericWithSpace(input, "_\\-");
    }
    public static boolean isAlphaNumericWithSpace(String input,
            String additionalValidChars) {

        /* patternString contains a space */
        String patternString = "([a-zA-Z0-9]+([ ][a-zA-Z0-9])*)+";

        if (additionalValidChars != null && additionalValidChars.length() > 0) {
            patternString = "([a-zA-Z0-9]+[ ]?(([" + additionalValidChars
                    + "][a-zA-Z0-9 ])*)?[" + additionalValidChars + "]?)+";
        }
        Pattern pattern = Pattern.compile(patternString);
        return pattern.matcher(input).matches();
    }

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