full code:

public class DomainValidation {

// ***********************************************************************

/** getPeriodPosition - Get the position of a single period in a string. @param stringToSearch - The string to search for periods @return N >=0, the position of the single period in the string N

public static int getPeriodPosition(String stringToSearch) { int stringLength = stringToSearch.length(); int periodCounter = 0; int periodPosition = -1; int i = 0; for (i = 0; i

// If there are zero or two or more periods, indicate an incorrect domain // name by setting variable periodPosition to -1 if (periodCounter != 1) { periodPosition = -1; } return periodPosition; } // ***********************************************************************

/** hasValidSecondLevel - Checks if the second level domain part is valid @param secondLevel - The candidate second-level domain @return true - The second-level domain is valid false - The second-level domain is not valid

A valid second-level domain: 1. Is between 1 and 63 characters long 2. Contains only upper- and lower-case letters, digits 0-9 and the dash 3. Cannot begin or end with a dash */ public static boolean hasValidSecondLevel(String secondLevel) { final int MAX_SECONDLEVEL_LENGTH = 63; final char DASH = '-'; boolean isValidSecondLevel = true; // Assume valid second-level domain int secondLevelLength = secondLevel.length(); char nextChar = '?'; int i = 0; // Disqualify the second-level domain if it is too short or too long, or // if it begins or ends with a dash if ((secondLevelLength >= 1) && (secondLevelLength

// ***********************************************************************

/** hasValidTld - Checks if the top-level domain part is valid @param theTld - The candidate top-level domain @return true - The top-level domain is valid false - The top-level domain is not valid

A valid top-level domain begins with a period and then contains only upper- and lower-case letters, or digits 0-9. */ public static boolean hasValidTld(String theTld) { boolean isValidTopLevel = true; // Assume valid top-level domain int topLevelLength = theTld.length(); char nextChar = '?'; int i = 0; // Disqualify the top-level domain if it is the empty string or // the first character is not a period

if ((topLevelLength

// Disqualify the top-level domain if any character is not a letter // or a digit i = 1; while ((i

// ***********************************************************************

/** isSpecialGtld - Checks if the TLD part is a special gTLD @param specialGtld - An array of valid special gTLD names @param tld - A candidate top-level domain name @return true - The TLD is a special gTLD false - The TLD is not a special gTLD

*/ public static boolean isSpecialGtld(String [] specialGtld, String tld) { boolean isSpecial = false; int i = 0; i = 0; while ((i

// ***********************************************************************

/** FIXME: Write a method getString with the following specifications: getString - Prompts for an input string from the user @param input - the source of the input (a Scanner object) @param prompt - the prompt to show the user @return The string entered by the user (which could be empty) */ // FIXME: Insert the getString method here // ***********************************************************************

public static void main (String [] args) { final String PROMPT_DOMAIN_NAME = " Enter the next domain name (Enter to exit): "; Scanner scnr = new Scanner(System.in); // Define the list of valid core gTLDs and restricted gTLDs String [] validCoreGtld = { ".com", ".net", ".org", ".info" }; String [] validRestrictedGtld = { ".biz", ".name", ".pro" }; String inputName = ""; String searchName = ""; String secondLevel = ""; // In aaa.bbb, the aaa part, aka second-level domain String theTld = ""; // In aaa.bbb, the bbb part, aka top-level domain int periodPosition = 0; boolean isCoreGtld = false; boolean isPeriodPositionValid = false; boolean isRestrictedGtld = false; boolean isDomainValid = false;

int i = 0;

// Get the first domain name to process // FIXME: Rewrite the prompt for an input of the next domain // name as a call to a method named getString. The method // has parameters Scanner for the input source and a String // prompt to display to the user. System.out.println(PROMPT_DOMAIN_NAME); inputName = scnr.nextLine();

while (inputName.length() > 0) { searchName = inputName.toLowerCase(); isCoreGtld = false; isDomainValid = false; periodPosition = getPeriodPosition(searchName); isPeriodPositionValid = (periodPosition >= 1);

// The domain name is valid if there is exactly one period in the // domain name (at location periodPosition) and the domain name does // not start or end with a period. Note that a period position of 0 means // the first character is a period, rendering the domain name invalid if ((periodPosition > 0) && (searchName.charAt(searchName.length() - 1) != '.')) { isPeriodPositionValid = true; } else { isPeriodPositionValid = false; } if (isPeriodPositionValid) {

// Extract the second-level domain and the top-level domain secondLevel = searchName.substring(0, periodPosition); theTld = searchName.substring(periodPosition); isDomainValid = hasValidSecondLevel(secondLevel) && hasValidTld(theTld);

// If the domain name is valid see if there is a core gTLD // or a restricted gTLD if (isDomainValid) { isCoreGtld = isSpecialGtld(validCoreGtld, theTld); if (!isCoreGtld) { // FIXME: Using method isSpecialGtld with the array // validRestrictedGtld, set isRestrictedGtld to // true or false based on whether the gTLD is a // restricted gTLD.

} } } // Display the results System.out.print("\"" + inputName + "\" "); if (isDomainValid) { System.out.print("is a valid domain name and "); if (isCoreGtld) { System.out.println("has a core gTLD of \"" + theTld + "\"."); } else if (isRestrictedGtld) { System.out.println("has a restricted gTLD of \"" + theTld + "\"."); } else { System.out.println("has a TLD of \"" + theTld + "\"."); } } else { System.out.println("is not a valid domain name."); }

// Get the next domain name to process // FIXME: Use the getString method described above to prompt for // and input the next candidate domain name. System.out.println(PROMPT_DOMAIN_NAME); inputName = scnr.nextLine(); } return; } }

Second Code:

public class DomainValidation_Solution {

// ***********************************************************************

/** getPeriodPosition - Get the position of a single period in a string @param stringToSearch - The string to search for periods @return N >=0, the position of the single period in the string N

public static int getPeriodPosition(String stringToSearch) { int stringLength = stringToSearch.length(); int periodCounter = 0; int periodPosition = -1; int i = 0; for (i = 0; i

// If there are zero or two or more periods, indicate an incorrect domain // name by setting variable periodPosition to -1 if (periodCounter != 1) { periodPosition = -1; } return periodPosition; }

// ***********************************************************************

/** hasValidSecondLevel - Checks if the second level domain part is valid @param secondLevel - The candidate second-level domain @return true - The second-level domain is valid false - The second-level domain is not valid

A valid second-level domain: 1. Is between 1 and 63 characters long 2. Contains only upper- and lower-case letters, digits 0-9 and the dash 3. Cannot begin or end with a dash */ public static boolean hasValidSecondLevel(String secondLevel) { final int MAX_SECONDLEVEL_LENGTH = 63; final char DASH = '-'; boolean isValidSecondLevel = true; // Assume valid second-level domain int secondLevelLength = secondLevel.length(); char nextChar = '?'; int i = 0; // Disqualify the second-level domain if it is too short or too long, or // if it begins or ends with a dash if ((secondLevelLength >= 1) && (secondLevelLength

// ***********************************************************************

/** hasValidTld - Checks if the top-level domain part is valid @param theTld - The candidate top-level domain @return true - The top-level domain is valid false - The top-level domain is not valid

A valid top-level domain begins with a period and then contains only upper- and lower-case letters, or digits 0-9. */ public static boolean hasValidTld(String theTld) { boolean isValidTopLevel = true; // Assume valid top-level domain int topLevelLength = theTld.length(); char nextChar = '?'; int i = 0; // Disqualify the top-level domain if it is the empty string or // the first character is not a period

if ((topLevelLength

// Disqualify the top-level domain if any character is not a letter // or a digit i = 1; while ((i

// ***********************************************************************

/** isSpecialGtld - Checks if the TLD part is a special gTLD @param specialGtld - An array of valid special gTLD names @param tld - A candidate top-level domain name @return true - The TLD is a special gTLD false - The TLD is not a special gTLD

*/ public static boolean isSpecialGtld(String [] specialGtld, String tld) { boolean isSpecial = false; int i = 0; i = 0; while ((i

// ***********************************************************************

/** getString - Prompts for an input string from the user @param input - the source of the input (a Scanner object) @param prompt - the prompt to show the user @return The string entered by the user (which could be empty) */ public static String getString(Scanner input, String prompt) { String userInput; System.out.println(prompt); userInput = input.nextLine();

return userInput; } // ***********************************************************************

public static void main (String [] args) { final String PROMPT_DOMAIN_NAME = " Enter the next domain name (Enter to exit): "; Scanner scnr = new Scanner(System.in); // Define the list of valid core gTLDs and restricted gTLDs String [] validCoreGtld = { ".com", ".net", ".org", ".info" }; String [] validRestrictedGtld = { ".biz", ".name", ".pro" }; String inputName = ""; String searchName = ""; String secondLevel = ""; // In aaa.bbb, the aaa part, aka second-level domain String theTld = ""; // In aaa.bbb, the bbb part, aka top-level domain int periodPosition = 0; boolean isCoreGtld = false; boolean isPeriodPositionValid = false; boolean isRestrictedGtld = false; boolean isDomainValid = false;

int i = 0;

// Get the first domain name to process inputName = getString(scnr, PROMPT_DOMAIN_NAME);

while (inputName.length() > 0) { searchName = inputName.toLowerCase(); isCoreGtld = false; isDomainValid = false; periodPosition = getPeriodPosition(searchName);

// The domain name is valid if there is exactly one period in the // domain name (at location periodPosition) and the domain name does // not start or end with a period. Note that a period position of 0 means // the first character is a period, rendering the domain name invalid if ((periodPosition > 0) && (searchName.charAt(searchName.length() - 1) != '.')) { isPeriodPositionValid = true; } else { isPeriodPositionValid = false; }

if (isPeriodPositionValid) { // Extract the second-level domain and the top-level domain secondLevel = searchName.substring(0, periodPosition); theTld = searchName.substring(periodPosition); isDomainValid = hasValidSecondLevel(secondLevel) && hasValidTld(theTld);

// If the domain name is valid see if there is a core gTLD // or a restricted gTLD if (isDomainValid) { isCoreGtld = isSpecialGtld(validCoreGtld, theTld); if (!isCoreGtld) { isRestrictedGtld = isSpecialGtld(validRestrictedGtld, theTld); } } } // Display the results System.out.print("\"" + inputName + "\" "); if (isDomainValid) { System.out.print("is a valid domain name and "); if (isCoreGtld) { System.out.println("has a core gTLD of \"" + theTld + "\"."); } else if (isRestrictedGtld) { System.out.println("has a restricted gTLD of \"" + theTld + "\"."); } else { System.out.println("has a TLD of \"" + theTld + "\"."); } } else { System.out.println("is not a valid domain name."); }

// Get the next domain name to process inputName = getString(scnr, PROMPT_DOMAIN_NAME); } return; } }