JAVA PROGRAMMING

Arrays are useful to process lists.

A top-level domain (TLD) name is the last part of an Internet domain name like .com in example. com. A core generic top-level domain (core gTLD) is a TLD that is either .com, .net, .org, or .info. A restricted top-level domain is a TLD that is either .biz, .name, or .pro. A second-level domain is a single name that precedes a TLD as in apple in apple. com.

The following program repeatedly prompts for a domain name, and indicates whether that domain name consists of a second-level domain followed by a core gTLD. Valid core gTLD's are stored in an array. For this program, a valid domain name must contain only one period, such as apple. com, but not support. apple. com. The program ends when the user presses just the Enter key in response to a prompt.

1-Run the program and enter domain names to validate.

2-Extend the program to also recognize restricted TLDs using an array, and statements to validate against that array. The program should also report whether the TLD is a core gTLD or a restricted gTLD. Run the program again.

import java. util. Scanner;

public class GtldValidation {

public static void main (String [ ] args) {
Scanner scnr = new Scanner(System. in);

// Define the list of valid core gTLDs
String [ ] validCoreGtld = { ".com", ".net", ".org", ".info" };
// FIXME: Define an array named validRestrictedGtld that has the names
// of the restricted domains, .biz, .name, and .pro
String inputName = "";
String searchName = "";
String theGtld = "";
boolean isValidDomainName = false;
boolean isCoreGtld = false;
boolean isRestrictedGtld = false;
int periodCounter = 0;
int periodPosition = 0;
int i = 0;

System. out. println("\nEnter the next domain name ( to exit): ");
inputName = scnr. nextLine();

while (inputName. length() > 0) {

searchName = inputName. toLowerCase();
isValidDomainName = false;
isCoreGtld = false;
isRestrictedGtld = false;

// Count the number of periods in the domain name
periodCounter = 0;
for (i = 0; i < searchName. length(); ++i) {
if (searchName. charAt(i) == '.') {
++periodCounter;
periodPosition = i;
}
}

// If there is exactly one period that is not at the start
// or end of searchName, check if the TLD is a core gTLD or a restricted gTLD
if ((periodCounter == 1) &&
(searchName. charAt(0) != '.') &&
(searchName. charAt(searchName. length() - 1) != '.')) {
isValidDomainName = true;
}
if (isValidDomainName) {
// Extract the Top-level Domain name starting at the period's position. Ex:
// If searchName = "example. com", the next statement extracts ".com"
theGtld = searchName. substring(periodPosition);

i = 0;
while ((i < validCoreGtld. length) && (!isCoreGtld)) {
if(theGtld. equals(validCoreGtld[i])) {
isCoreGtld = true;
}
else {
++i;
}
}

// FIXME: Check to see if the gTLD is not a core gTLD. If it is not,
// check to see whether the gTLD is a valid restricted gTLD.
// If it is, set isRestrictedGtld to true

}

System. out. print("\"" + inputName + "\" ");
if (isValidDomainName) {
System. out. print("is a valid domain name and ");
if (isCoreGtld) {
System. out. println("has a core gTLD of \"" + theGtld + "\".");
}
else if (isRestrictedGtld) {
System. out. println("has a restricted gTLD of \"" + theGtld + "\".");
}
else {
System. out. println("does not have a core gTLD."); // FIXME update message
}
}
else {
System. out. println("is not a valid domain name.");
}

System. out. println("\nEnter the next domain name ( to exit): ");
inputName = scnr. nextLine();
}

return;
}
}