Email Validation Script

Summary

Email Validator Program developed using pure Object Oriented Programming & String handling in Java during college days as an assignment.

Ability of Validating

Username

[email protected] INVALID
[email protected] INVALID
[email protected] INVALID
rohan^[email protected] INVALID
[email protected] INVALID
[email protected] INVALID

[email protected] VALID
[email protected] VALID
[email protected] VALID
[email protected] VALID

Special character “@”

[email protected]@gmail.com INVALID
[email protected]@gmail.com INVALID
@@gmail.com INVALID
[email protected] VALID

Domain Name

[email protected] INVALID
[email protected] INVALID
[email protected] INVALID
[email protected] INVALID
[email protected] INVALID
[email protected]_gmail.com INVALID

[email protected] VALID
[email protected] VALID
[email protected]VALID
[email protected] VALID
[email protected] VALID

Code

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/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package emailverifieroop;

import java.io.*;

/**
*
* @author RohanSakhale
*/
public class EmailVerifier {

String s;

public EmailVerifier() {
s = "";
}

public EmailVerifier(String s) {
this.s = s;
}

void setEmail(String email) {
this.s = email;
}

/**
* Accept string from user
*/
void accept() throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
s = br.readLine();
br.close();
}

/**
* Display string entered
*/
void display() {
System.out.println("You have entered: " + s);
}

/**
* Validate username from email
*/
boolean checkUsername() {
if (s.length() >= 3) {
for (int i = 0; i < s.indexOf("@"); i++) {
if (i != 0 && (s.charAt(i) == '_' || s.charAt(i) == '.')) {
continue;
}
if ((int) s.charAt(i) < 47 && (int) s.charAt(i) > 58) {
if (s.startsWith(Integer.toString(i)) == true) {
return false;
}
}
if ((int) s.charAt(i) < 47) {
return false;
} else if ((int) s.charAt(i) > 57 && (int) s.charAt(i) < 65) {
return false;
} else if ((int) s.charAt(i) > 91 && (int) s.charAt(i) < 97) {
return false;
} else if ((int) s.charAt(i) > 123) {
return false;
}
}
return true;
} else {
return false;
}
}

/**
* Validate email username
*/
boolean checkEmailUsername() {
if (s.indexOf("@") >= 3 && s.charAt(s.indexOf("@") - 1) != '.' && s.charAt(s.indexOf("@") - 1) != '_') {
for (int i = 0; i < s.indexOf("@"); i++) {
if (i != 0 && (s.charAt(i) == '_' || s.charAt(i) == '.')) {
continue;
}
if ((int) s.charAt(i) < 47 && (int) s.charAt(i) > 58) {
if (s.startsWith(Integer.toString(i)) == true) {
return false;
}
}
if ((int) s.charAt(i) < 47) {
return false;
} else if ((int) s.charAt(i) > 57 && (int) s.charAt(i) < 65) {
return false;
} else if ((int) s.charAt(i) > 91 && (int) s.charAt(i) < 97) {
return false;
} else if ((int) s.charAt(i) > 123) {
return false;
}
}
return true;
} else {
return false;
}
}

/**
* Validate "@" exists
*/
boolean checkPresenceOfSymbol() {
if (s.indexOf("@") == -1) {
return false;
} else {
return true;
}
}

/**
* Validate "@" is not the last character of string
*/
boolean checkEmailSymbol() {
if (s.indexOf("@") == s.lastIndexOf("@")) {
return true;
} else {
return false;
}

}

/**
* Validate the domain name
*/
boolean checkDomainName() {
int count = 0;
if (s.charAt(s.indexOf("@") + 1) == '_' || s.charAt(s.indexOf("@") + 1) == '-') {
return false;
}
if (s.indexOf(".", s.indexOf("@")) - s.indexOf("@") >= 3) {
for (int i = s.indexOf("@") + 1; i < s.length(); i++) {
if (s.charAt(i) == '.') {
count++;
if (count > 2) {
return false;
}
}
}
for (int i = s.indexOf("@") + 1; i < s.length(); i++) {
if ((s.charAt(i) == '.' || s.charAt(i) == '-')
|| s.indexOf("-") - s.indexOf("@") > 1) {
continue;
}

if ((int) s.charAt(i) < 47) {
return false;
}

if ((int) s.charAt(i) > 47 && (int) s.charAt(i) < 57) {
continue;

}
if ((int) s.charAt(i) < 97) {
return false;
}
if ((int) s.charAt(i) > 123) {
return false;
}

}
if (s.lastIndexOf(".") == s.length() - 4) {
return true;
} else if (s.lastIndexOf(".") == s.length() - 3) {
return true;
} else if (s.indexOf(".", s.indexOf("@")) == s.length() - 2 && s.lastIndexOf(".") == s.length() - 5) {
return true;
} else {
return false;
}
} else {
return false;
}
}

/**
* Validate string as email
*/
boolean checkEmail() {
if (!checkEmailUsername()) {
return false;
}
if (!checkPresenceOfSymbol()) {
return false;
}
if (!checkDomainName()) {
return false;
}
if (!checkEmailSymbol()) {
return false;
}
return true;
}

}