base.email.EmailAddressParse Maven / Gradle / Ivy

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/**
 * Creative commons Attribution-NonCommercial license.
 *
 * http://creativecommons.org/licenses/by-nc/2.5/au/deed.en_GB
 *
 * NO WARRANTY IS GIVEN OR IMPLIED, USE AT YOUR OWN RISK.
 */
package base.email;

import java.util.ArrayList;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class EmailAddressParse {

	/**
	 * Create a list of validated email addresses from a user entered, possibly badly formed string.
	 * getError()
	 *
	 * @param line
	 * @return List of validated email addresses.
	 * @see base.email.EmailAddressParse#getError()
	 */
	public EmailAddress[] parse(String line) {
		error = null;

		List parts = new ArrayList();
		String part = "";
		int mode = 0;
		char escapeType = 0;
		for(int i = 0; i < line.length(); i++) {
			char c = line.charAt(i);
			switch(mode) {
				case 0 :
					if(c == ' ' || c == '\t' || c == '\n' || c == ',') {
						if(part.length() > 0) {
							parts.add(part);
						}
						part = "";
						continue;
					}
					if(c == '<' || c == '"' || c == '\'') {
						if(c == '<' && part.length() > 0) {
							parts.add(part);
							part = "";
						}
						escapeType = c;
						if(c == '<') {
							escapeType='>';
						}
						mode = 1;
						continue;
					}
					part = part+c;
					break;
				case 1 :
					if(c == escapeType) {
						if(c == '>' && part.length() > 0) {
							parts.add(part);
							part = "";
						}
						mode = 0;
						continue;
					}
					part = part+c;
					break;
			}
		}
		if(part.length() > 0) {
			parts.add(part);
		}

		List addresses = new ArrayList();
		String name = "";
		for(String bit : parts) {
			if(bit.contains("@")) {
				if(name == "") {
					addresses.add(new EmailAddress(bit));
				} else {
					addresses.add(new EmailAddress(name, bit));
				}
				name = "";
			} else {
				if(name == "") {
					name = bit;
				} else {
					name = name + " " + bit;
				}
			}
		}

		if(name.length() > 0) {
			error = "Name \"" + name + "\" appears without an associated email address.";
		}
		return addresses.toArray(new EmailAddress[0]);
	}


	/*
	 * Here are the pre-compiled regular expressions used to aide
	 * validation of email addresses.
	 */
	private static Pattern invalidNameCharacters = Pattern.compile(".*([\\\\\\/\\*\\&\\(\\)\\!\\#\\$\\%\\^\\~\\`\\{\\}\\;\\:\\\"\\,\\<\\>\\?\\[\\]\\=\\|]).*");
	private static Pattern partCheck = Pattern.compile("([^@]+)@([^@]+)");
	private static Pattern numberCheck = Pattern.compile(".*\\d.*");
	private static Pattern invalidDomainNameCharacters = Pattern.compile(".*([\\\\\\/\\*\\&\\(\\)\\!\\#\\$\\%\\^\\~\\`\\{\\}\\;\\:\\\"\\,\\<\\>\\?\\[\\]\\'\\=\\|]).*");

	/**
	 * Contains an error if a problem occurred with the most recent
	 * call to the email validating function isValid().
	 */
	private String error = null;

	/**
	 * Describes any problem with parsing email addresses, or null null
	 * if no problem occurred. Invoking getError() resets the error
	 * back to null.
	 *
	 * @return String containing the error message
	 */
	public String getError() {
		String e2 = error;
		error = null;
		return e2;
	}

	/**
	 * Test the validity of an email address, returning true if
	 * the email address is valid. You can follow this call with a call
	 * to getError() to discover the problem with the email address.
	 *
	 * @param email Email address to check
	 * @return True if valid, false if invalid
	 * @see base.email.EmailAddressParse#getError()
	 */
	public boolean isValid(String email) {

		if(email == null) {
			error = "Email address not provided.";
			return false;
		}

		if(email.length() < 6) {
			error="This is not long enough to be a valid e-mail address.";
			return false;
		}

		Matcher m = partCheck.matcher(email);
		if(!m.matches()) {
			error = "Email address must contain a single @ in the middle";
			return false;
		}

		String name = m.group(1);
		String domain = m.group(2);
		String[] domainParts = domain.split("\\.");

		if(domainParts.length <= 1) {
			error="Your email domain is incomplete.\n";
			return false;
		}

		if(domainParts[domainParts.length-1].length() < 2) {
			error = "Email domain appears to be invalid.";
			return false;
		}

		if(domainParts[domainParts.length-1].length() > 4) {
			error = "Email domain appears to be invalid.";
			return false;
		}

		m = numberCheck.matcher(domainParts[domainParts.length-1]);
		if(m.matches()) {
			error = "Email domain appears to be invalid.";
			return false;
		}

		m = invalidDomainNameCharacters.matcher(domain);
		if(m.matches()) {
			error = "The " + m.group(1) + " character may not be used in the domain name part of an email address.";
			return false;
		}

		m = invalidNameCharacters.matcher(name);
		if(m.matches()) {
			error = "The "+m.group(1)+" character may not be used in the name part of an email address.";
			return false;
		}

		if(email.indexOf("@") < 0) {
			error="Email address must contain the @ symbol.";
			return false;
		}

		if(email.indexOf(" ") >= 0) {
			error = "Email address should not contain a space.";
			return false;
		}

		return true;
	}
}