Review

class StringUtils {
    /**
     * <p>Checks if the String contains only unicode letters, digits
     * or space (<code>' '</code>).</p>
     *
     * <p><code>null</code> will return <code>false</code>.
     * An empty String ("") will return <code>true</code>.</p>
     *
     * <pre>
     * StringUtils.isAlphanumeric(null)   = false
     * StringUtils.isAlphanumeric("")     = true
     * StringUtils.isAlphanumeric("  ")   = true
     * StringUtils.isAlphanumeric("abc")  = true
     * StringUtils.isAlphanumeric("ab c") = true
     * StringUtils.isAlphanumeric("ab2c") = true
     * StringUtils.isAlphanumeric("ab-c") = false
     * </pre>
     *
     * @param str  the String to check, may be null
     * @return <code>true</code> if only contains letters, digits or space,
     *  and is non-null
     */
    public static boolean isAlphanumericSpace(String str) {
        if (str == null) {
            return false;
        }
        int sz = str.length();
        for (int i = 0; i < sz; i++) {
            if ((Character.isLetterOrDigit(str.charAt(i)) == false) && (str.charAt(i) != ' ')) {
                return false;
            }
        }
        return true;
    }

}