Checks if a string of text is fully valid. - Java java.lang

Java examples for java.lang:char

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Description

Checks if a string of text is fully valid.

Demo Code


//package com.java2s;

public class Main {
    public static void main(String[] argv) throws Exception {
        String str = "java2s.com";
        System.out.println(isValid(str));
    }//from w  ww .  j  a  va2 s  .c  o  m

    private final static String SPECIAL_CHARACTERS = "\'~=-+:;/*!@#$%^&*()\"{}_[]|\\?/<>,. ";

    /**
     * Checks if a string of text is fully valid. That is, every single character in the string is valid.
     * @param str a String to check for validity
     * @return a boolean, true if the string contains only valid characters; or false if it contains even one invalid character
     */
    public static boolean isValid(String str) {
        for (int i = 0; i < str.length(); i++) {
            if (!isLegitimateCharacter(str.charAt(i)))
                return false;
        }
        return true;
    }

    /**
     * Attempts to determine if a character is a legal alphabetic, digit, or special character. 
     * A special character is defined as any of the following:<i> /*!@#$%^&*()\"{}_[]|\\?/<>,. </i> (includes ' ')
     * @return a boolean which should indicate if the provided char is an alphabetic, digit, or special character 
     */
    private static boolean isLegitimateCharacter(char c) {
        return Character.isLetterOrDigit(c) || isSpecialCharacter(c);
    }

    /**
     * Determines if the provided character is a special character, that is to say it belongs to the following set:
     * <i>/*!@#$%^&*()\"{}_[]|\\?/<>,. </i> (includes ' ')
     * @param c a char to check against the set of special characters
     * @return a boolean, true if the provided char falls into the set of special characters, otherwise false
     */
    private static boolean isSpecialCharacter(char c) {
        for (int i = 0; i < SPECIAL_CHARACTERS.length(); i++) {
            if (c == SPECIAL_CHARACTERS.charAt(i)) {
                return true;
            }
        }
        return false;
    }
}

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