CSF Email Service Technical Spec

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1. Introduction

The CSF Email Service is a module in CSF to handle various functions related to sending emails to a single or group of recipients.

The implementation will include all the methods in the existing EmailServiceImpl in CSF common-legacy. New methods are added
to handle the bulk email and email preview functionality. In addition, new functionalities have been added to store the email message
created in the database and to retrieve the email queue status/statistics via service methods. The EmailServiceImpl is not annotated
so it has to be configured in one of the application Context files in the web application. It is not annotated so we can inject the
ApplicationConfiguration for those web applications that are using sais-common.

2. Dependencies

2.1 CSF base

We will utilize CSF base module to obtain the application configuration information.

2.2 CSF test

We will utilize CSF test module to facilitate the unit tests created for the email module

2.3 CSF orm

We will utilize CSF orm module to facilitate the IO operations of its dao.

3. Object Model

3.1 Class Diagram

The following domain classes are created to represent

(1) EmailModel is created to hold all the fields in an email message. It is used by other web application
     to pass data of the email to be sent to the EmailService.

The following diagram represents the domain class EmailModel.

(2) EmailEvent is a persistent object created to represent the persist object for each email that is queued or sent.
     Besides from address, to address, the cc and bcc list, it will also hold the full email text (i.e. content after
     translating the velocity template), a status (queued or sent), create date and a reference to the EmailAttachment
     persistent object if the email sent has attachment(s).

(3) EmailAttachment is a persistent object created to save the attachment associated with email events.

The following diagram represents the domain class EmailEvent and EmailAttachment and their relationship:

3.2 Class Description.

3.2.1 EmailModel

  This is the domain class that represents an Email Message object. It contains the following fields:

1. emailFrom – the email address of the sender
2. emailSubject – the subject of the email
3. emailTos – the list of email addresses of those who will be sent a copy of the email
4. emailCC – the list of email addresses of those will get a cc copy of the email.
5. emailBcc – the list of email addresses of those will get a bcc copy of the email.
6. emailReportRecipient – the list of email addresses of those who will get a copy of the summary report.
7. emailText – the content of the email.

3.2.2 EmailPerson

  This is the domain class that represents an Email Person object. It contains the following fields:

1. emailAddress -- the email address of the person
2. personName -- the full name of the person with the email address

3.2.3 EmailEvent

  This is the domain class that represents the persisted Email Event object. It contains the following fields:

1. emailFrom -- the email address of the sender.
2. emailTo – the recipient of the email
3. emailSubject – the subject of the email
4. emailCcs -- a comma-separated list of email address that will be sent a cc copy of the email
5. emailBccs -- a comma-separated list of email address that will be sent a bcc copy of the email
6. emailText -- the content of the email
7. html -- whether the email is in plain text or html text
8. statusFlag -- the status (Queued or Sent) of the email in the queue
9. createDate -- the date when the email was created
10. createBy -- the user who create the email
11. attachments -- set of attachment(s) that are associated with this email
12. appId -- the id of the application that creates the email

3.2.4 EmailAttachment

  This is the domain class that represents the persisted Email Attachment object. It contains the
  following fields:

1. seqNo -- the order of the email attachment.
2. document -- the byte array that stores the content of the attachment
3. filename -- the file name of the attachment file
4. mimeType -- the mime type of the attachment
5. emailEvents -- the list of email events associated with this attachment

4. Service Modules

4.1 Class Diagram

4.2 Class Descriptions.

4.2.1 EmailService Interface

This is the interface that defines the methods available for the other web applications to utilize when they are required
to send out emails to a single or a list of recipients. The service includes the following methods:

1. public void sendBulkEmail(EmailModel emailModel, String summaryReportTemplate, boolean defaultSort)
2. public void sendBulkEmailWithTemplate(EmailModel emailModel, String velocityTemplate, Map context, String summaryReportTemplate, boolean defaultSort)
3. public Map<String, Integer> sendBulkEmailWithCounts(EmailModel emailModel)
4. public Map<String, Object> generateEmailPreviewWithTemplate(EmailModel emailModel, String type, String velocityTemplate, Map context)
5. public Map<String, Object> generateSummaryReportPreview(EmailModel emailModel)
6. public void sendEmailWithAttachments(EmailModel emailModel, List<File> attachments)
7. public void sendEmailWithTemplateAndAttachments(EmailModel emailModel, String velocityTemplate, Map context, List<File> attachments)
8. public void sendEmailWithAttachmentsFromDataSource(EmailModel emailModel, List<File> attachments, boolean useApplicationConfig)
9. public void newEmail(String velocityTemplate, Map context, String to, String from, String subject, boolean html)
10. public void newEmail(String velocityTemplate, Map context, String[] tos, String from, String subject, boolean html)
11. public void newEmail(String velocityTemplate, Map context, String to, String subject, boolean html)
12. public void newEmail(String velocityTemplate, Map context, String[] tos, String subject, boolean html)
13. public void newEmail(String body, String to, String subject, boolean html)
14. public void newEmail(String from, List<EmailPerson) to, String subject, String body, String[] cc, String[] bcc, String[] rr, String velocityTemplate)
15. public void newEmail(String body, String[] tos, String from, String subject, String[] cc, String[] bcc, boolean html, List<File> attachments)
16. public void newEmail(String body, String from, String[] tos, String subject, String[] cc, String[] bcc, boolean html, List<DataSource> attachments, boolean overrideFromAddress)
17. public void newEmail(String from, String[] to, String subject, String body, String[] cc, String[] bcc, String[] rr)
18. public List getMessageQueue()
19. public void batchSend()
20. public boolean validateEmailAddress(String emailAddress)
21. public List getMessageQueue()
22. public List<String Object> getMessageQueueStatistics(Date fromDate, Date thruDate, String emailFrom, String emailTo, String status)
23. public void batchSend()
24. public void delete()
25. public boolean validateEmailAddress(String emailAddress)

4.2.3 EmailService Implementation

This is the implementation class for the EmailService. 

4.2.3.1 sendBulkEmail

This method obtains an EmailModelDomain Object. It will then process the data and call the newEmail method to save the email and
the summary report for the intended recipients. The call to the newEmail method should be configured with the following parameters:
newEmail(String from, String[] to, String subject, String body, String[] cc, String[] bcc, String[] rr);
The following attributes in the EmailModel Object will affect the generation of email:

1. a list of email addresses of the recipients specified in the "To" field <required>
2. a list of email addresses of the recipients specified in the "cc" field <optional>
3. a list of email addresses of the recipients specified in the "Bcc" field <optional>
4. a list of email addresses of the recipients speicified in the "Report Recipient" field <optional>
5. email subject<optional>
6. email text <required>

4.2.3.2 sendBulkEmailWithTemplate

This method obtains an EmailModel Object, a velocity template name and a map that contains the values for the variables in the template.
It will use the velocity template and the map to generate the text for the email. Then, it will call the sendBulkEmail method to create
and save the email message and the summary report for intended recipients.

4.2.3.3 sendBulkEmailWithCounts

This method obtains an EmailModel Object. It will call the sendBulkEmail method to create and save the email message and the summary
report to intended recipients. Then, it will call the BatchSend to send out the email and return the counts of successful and failed delivery.

4.2.3.4 generateEmailPreviewWithTemplate

This method obtains an EmailModel Object, a string to specify the type of preview, a velocity template name, and a Map that contains the values
for the variables within the velocity template. It will use the velocity template and the map to generate the text for the email. Then, it will
updated the email tect to the email model object and put the updated object into the returned Map. If a summary report preview is required, it
will call the generateSummaryReportPreview method to add the attributes necessary to generate the summary report preview to the returned map.

4.2.3.5 generateSummaryReportPreview

This private method adds the objects/attributes necessary to create a preview of the summary report. The objects to be added are as follows:

1. A String that contains the content of the summary report

4.2.3.6 sendEmailWithAttachments

This method accepts an EmailModel object and a list of attachments. It will then call newEmail method to create and save the message(s) in database.

4.2.3.7 sendEmailWithTemplateAndAttachments

This method accepts an EmailModel object, a velocity template name, a map of replaced values, and a list of File objects (attachments). It will then
merge the velocity template with the replace values. Afterwards, it will call sendEmailWithAttachments to create and save the message(s) in database.

4.2.3.8 sendEmailWithAttachmentsFromDataSource

 This method accepts an EmailModel object and a list of DataSource objects(attachments)  and a boolean to signal the system to use the from
 address in the applicationConfiguration or not. It will then call newEmail method to create and save the message(s) in database

4.2.3.9 newEmail

These sets of methods are the same public methods available in the EmailService in the CSF common-legacy module.

4.2.3.10 sendReportRecipientEmail

4.2.3.11 createReportRecipientContent

This method is a public method migrated over from the EmailServiceImpl in common-legacy module.

4.2.3.12 saveMessage

This is a private method that are is called within the EmailServiceImpl to save the email message (just text
and with a list of File objects as attachments)  in database tables.

4.2.3.13 saveMessageWithAttachmentAsDataSource

This is a private method that is called within the EmailServiceImpl to save the email message with a list of
DataSource objects as attachments in database tables.

4.2.3.14 updateDataToEmailEvent

This is a private method that are is called within the EmailServiceImpl to update the data to the EmailEvent  table.

4.2.3.15 updateApplicationConfigurationParametersToEmailEvent

This is a protected method that are is called within the EmailServiceImpl to update the data to the EmailEvent object
according to properties configured by the application .

4.2.3.16 updateMessageContent

This is a private method that are is called within the EmailServiceImpl by various prepare method to update the
MimeMessage object with data from the database.

4.2.3.17 createMimeMessagePreparatorForEmailWithCcBccAttachments

This is a private method that are is called within the EmailServiceImpl to create a MimeMessage preparator instance
for email message with an attachments from the EmailEvent object retrieved from database.

4.2.3.18 createMimeMessagePreparatorForEmail

This is a private method that are is called within the EmailServiceImpl to create a MimeMessage preparator instance
for email message without an attachments from the EmailEvent data retrieved from the database.

4.2.3.19 prepare

The 4 prepare methods are static public methods that are available to create the MimeMessage object for each email
message.

4.2.3.20 batchSend

This method is a public method migrated over from the EmailServiceImpl in common-legacy module.

4.2.3.21 sendMessage

This is a private method that is called within the EmailServiceImpl to send the email message via the email server.

4.2.3.22 getMessageQueue

This method is a public method migrated over from the EmailServiceImpl in common-legacy module.

4.2.3.23 getMessageQueueStatistics

This method is a public method that will retrieve statistics from the database based on criteria including from date,
thru date, email from, email to, and status

4.2.3.24 validateEmailAddress

This method takes an input of email address in String and validate if the email address is valid. If the email address is valid, it will return
true. If not, it will return false. The input email address is validated according to the following conditions:

1. The system will create a new InternetAddress object using the input email address and then invoke the validate method of the InternetAddress object to verify it is a real email address

4.2.3.25 delete

This method deletes records from the email event and email attachment tables, based on a configurable parameter: email.in.system.days,
If not specify, the email for an application will be deleted in 5 days by dafault.

4.2.3.26 getTemplatePath

This method returns the path where the velocity template locates.

4.2.3.27 getFileSeparator

This method takes returns the file separator string for the system EmailService is running on.

4.2.3.28 isTomcatServer

This method checks if the system running the EmailService is a tomcat server. It will return a Boolean.

4.2.3.29 isErrorInEmailMetaData

This method takes will verify if the pass in parameter is in the correct format.

4.2.3.30 getMimeType

This method returns the MimeType of the file

4.2.3.31 handleException

 This is a private method that prints out the exception message and stack trace to log.

4.2.3.32 nonNullizeArray

An utility method to replace the null with an empty array if a method passed a null String array as a Cc or Bcc list