refactor(MailgunEmailSendingStrategy): introduce a value object instead of passing many arguments.

Related to #935

No functional changes.

Author: php-coder

src/main/java/ru/mystamps/web/service/MailServiceImpl.java

@@ -75,15 +75,13 @@ public void sendActivationKeyToUser(SendUsersActivationDto activation) {
 		Validate.isTrue(activation.getLang() != null, "Language must be non null");
 		Validate.isTrue(activation.getActivationKey() != null, "Activation key must be non null");
 
-		mailer.send(
-			activation.getEmail(),
-			robotEmail,
-			"My Stamps",
-			getSubjectOfActivationMail(activation),
-			getTextOfActivationMail(activation),
-			"activation_key",
-			testMode
-		);
+		MailgunEmail email = prepareEmail()
+			.recipientAddress(activation.getEmail())
+			.subject(getSubjectOfActivationMail(activation))
+			.text(getTextOfActivationMail(activation))
+			.tag("activation_key");
+		
+		mailer.send(email);
 
 		LOG.info(
 			"Email with activation code has been sent to {} (lang: {})",
@@ -95,15 +93,14 @@ public void sendActivationKeyToUser(SendUsersActivationDto activation) {
 	@Override
 	@Async
 	public void sendDailyStatisticsToAdmin(AdminDailyReport report) {
-		mailer.send(
-			adminEmail,
-			robotEmail,
-			"My Stamps",
-			getSubjectOfDailyStatisticsMail(report),
-			reportService.prepareDailyStatistics(report),
-			"daily_statistics",
-			testMode
-		);
+		
+		MailgunEmail email = prepareEmail()
+			.recipientAddress(adminEmail)
+			.subject(getSubjectOfDailyStatisticsMail(report))
+			.text(reportService.prepareDailyStatistics(report))
+			.tag("daily_statistics");
+		
+		mailer.send(email);
 
 		String date = shortDatePrinter.format(report.getStartDate());
 
@@ -115,6 +112,13 @@ public void sendDailyStatisticsToAdmin(AdminDailyReport report) {
 		);
 	}
 
+	private MailgunEmail prepareEmail() {
+		return new MailgunEmail()
+			.senderAddress(robotEmail)
+			.senderName("My Stamps")
+			.testMode(testMode);
+	}
+	
 	private String getTextOfActivationMail(SendUsersActivationDto activation) {
 		String template = messageSource.getMessage("activation.text", null, activation.getLocale());
 

src/main/java/ru/mystamps/web/service/MailgunEmail.java

@@ -0,0 +1,40 @@
+/*
+ * Copyright (C) 2009-2019 Slava Semushin <[email protected]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+package ru.mystamps.web.service;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.experimental.Accessors;
+
+@Accessors(fluent = true)
+@Getter
+@Setter
+class MailgunEmail {
+	private String recipientAddress;
+	private String senderAddress;
+	private String senderName;
+	private String subject;
+	private String text;
+
+	// There fields are fully Mailgun-specific.
+	//
+	// a tag for messages categorization
+	private String tag;
+	// tells Mailgun to accept a message but don't send it
+	private boolean testMode;
+}

src/main/java/ru/mystamps/web/service/MailgunEmailSendingStrategy.java

@@ -27,25 +27,11 @@ public interface MailgunEmailSendingStrategy {
 	/**
 	 * Send an e-mail.
 	 *
-	 * @param toEmail recipient address
-	 * @param fromEmail sender address
-	 * @param fromName sender name
-	 * @param subject mail subject
-	 * @param text mail body
-	 * @param tag a tag for messages categorization in Mailgun
-	 * @param testMode tells Mailgun to accept a message but don't send it
+	 * @param email data and meta-data for sending an e-mail
 	 * @throws ru.mystamps.web.service.exception.EmailSendingException when any error occurs
 	 * @see SmtpMailgunEmailSendingStrategy
 	 * @see <a href="https://documentation.mailgun.com/en/latest/user_manual.html#tagging">Tagging</a>
 	 * @see <a href="https://documentation.mailgun.com/en/latest/user_manual.html#sending-in-test-mode">Sending in Test Mode</a>
 	 */
-	@SuppressWarnings("PMD.UseObjectForClearerAPI")
-	void send(
-		String toEmail,
-		String fromEmail,
-		String fromName,
-		String subject,
-		String text,
-		String tag,
-		boolean testMode);
+	void send(MailgunEmail email);
 }

src/main/java/ru/mystamps/web/service/SmtpMailgunEmailSendingStrategy.java

@@ -39,31 +39,26 @@ public class SmtpMailgunEmailSendingStrategy implements MailgunEmailSendingStrat
 	private final JavaMailSender mailer;
 
 	@Override
-	@SuppressWarnings("PMD.UseObjectForClearerAPI")
-	public void send(
-		String toEmail,
-		String fromEmail,
-		String fromName,
-		String subject,
-		String text,
-		String tag,
-		boolean testMode) {
+	public void send(MailgunEmail email) {
 
 		try {
 			// We're using MimeMessagePreparator only because of its capability of adding headers.
 			// Otherwise we would use SimpleMailMessage class.
 			MimeMessagePreparator preparator = new MimeMessagePreparator() {
 				@Override
 				public void prepare(MimeMessage mimeMessage) throws Exception {
+					InternetAddress from =
+						new InternetAddress(email.senderAddress(), email.senderName(), "UTF-8");
+					
 					MimeMessageHelper message = new MimeMessageHelper(mimeMessage, "UTF-8");
 					message.setValidateAddresses(true);
-					message.setTo(toEmail);
-					message.setFrom(new InternetAddress(fromEmail, fromName, "UTF-8"));
-					message.setSubject(subject);
-					message.setText(text);
+					message.setTo(email.recipientAddress());
+					message.setFrom(from);
+					message.setSubject(email.subject());
+					message.setText(email.text());
 
-					message.getMimeMessage().addHeader("X-Mailgun-Tag", tag);
-					if (testMode) {
+					message.getMimeMessage().addHeader("X-Mailgun-Tag", email.tag());
+					if (email.testMode()) {
 						message.getMimeMessage().addHeader("X-Mailgun-Drop-Message", "yes");
 					}
 				}
@@ -72,7 +67,7 @@ public void prepare(MimeMessage mimeMessage) throws Exception {
 			mailer.send(preparator);
 
 		} catch (MailException ex) {
-			throw new EmailSendingException("Can't send mail to e-mail " + toEmail, ex);
+			throw new EmailSendingException("Can't send mail to " + email.recipientAddress(), ex);
 		}
 	}