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Chapter 12. E-Mail Support

This chapter describes the "out-of-the-box" e-mail support available in the JPDL. Read this information to learn how to configure different aspects of the mail functionality.

12.1.  Mail in JPDL

There are four ways in which one can specify the point in time at which e-mails are to be sent from a process.

12.1.1.  Mail Action

Use a mail action if there is a reason not to show the e-mail as a node in the process graph.

Note

A mail action can be added to the process anywhere that a normal action can be added. 
<mail actors="#{president}" subject="readmylips" text="nomoretaxes" />
Specify the subject and text attributes as an element like this: 
<mail actors="#{president}" >
    <subject>readmylips</subject>
    <text>nomoretaxes</text>
</mail>
Each of the fields can contain JSF-like expressions: 
<mail
    to='#{initiator}'
    subject='websale'
    text='your websale of #{quantity} #{item} was approved' />

Note

To learn more about expressions, see Section 14.3, “ Expressions ”.
Two attribute specify the recipients: actors and to. The to attribute should "resolve" to a semi-colon separated list of e-mail addresses. The actors attribute should resolve to a semi-colon separated list of actorIds. These actorIds will, in turn, resolve to e-mail addresses. (Refer to Section 12.3.3, “ Address Resolving ” for more details.) 
<mail 
    to='admin@mycompany.com' 
    subject='urgent'
    text='the mailserver is down :-)' />

Note

To learn how to specify recipients, read Section 12.3, “ Specifying E-Mail Recipients ”
e-Mails can be defined by the use of templates. Overwrite template properties in this way: 
<mail template='sillystatement' actors="#{president}" />

Note

Learn more about templates by reading Section 12.4, “ E-Mail Templates ”

12.1.2.  Mail Node

As with mail actions, the action of sending an e-mail can be modeled as a node. In this case, the run-time behavior will be identical but the e-mail will display as a node in the process graph.
Mail nodes support exactly the same attributes and elements as the mail action. (See Section 12.1.1, “ Mail Action ” to find out more.) 
<mail-node  name="send email" 
            to="#{president}"
            subject="readmylips" 
            text="nomoretaxes">
    <transition to="the next node" />
</mail-node>

Important

Always ensure that mail nodes have exactly one leaving transition.

12.1.3.  "Task Assigned" E-Mail

A notification e-mail can be sent when a task is assigned to an actor. To configure this feature, add the notify="yes" attribute to a task in the following manner: 
<task-node name='a'>
    <task name='laundry' swimlane="grandma" notify='yes' />
    <transition to='b' />
</task-node>
Set notify to yes, true or on to make the Business Process Manager send an e- mail to the actor being assigned to the task. (Note that this e- mail is based on a template and contains a link to the web application's task page.)

12.1.4.  "Task Reminder" E-Mail

e-Mails can be sent as task reminders. The JPDL's reminder element utilizes the timer. The most commonly used attributes are duedate and repeat. Note that actions do not have to be specified. 
<task-node name='a'>
    <task name='laundry' swimlane="grandma" notify='yes'>
        <reminder duedate="2 business days" repeat="2 business hours"/>
    </task>
    <transition to='b' />
</task-node>

12.2.  Expressions in Mail

The fields to, recipients, subject and text can contain JSF-like expressions. (For more information about expressions, see Section 14.3, “ Expressions ”.)
One can use the following variables in expressions: swimlanes, process variables and transient variables beans. Configure them via the jbpm.cfg.xml file.
Expressions can be combined with address resolving functionality. (Refer to Section 12.3.3, “ Address Resolving ”. for more information.)
This example pre-supposes the existence of a swimlane called president: 
<mail   actors="#{president}" 
        subject="readmylips" 
        text="nomoretaxes" />
The code will send an e-mail to the person that acts as the president for that particular process execution.

12.3.  Specifying E-Mail Recipients

12.3.1. Multiple Recipients

Multiple recipients can be listed in the actors and to fields. Separate items in the list with either a colon or a semi-colon.

12.3.2.  Sending E-Mail to a BCC Address

In order to send messages to a Blind Carbon Copy (BCC) recipient, use either the bccActors or the bcc attribute in the process definition. 
<mail to='#{initiator}' 
      bcc='bcc@mycompany.com' 
      subject='websale' 
      text='your websale of #{quantity} #{item} was approved' />
An alternative approach is to always send BCC messages to some location that has been centrally configured in jbpm.cfg.xml. This example demonstrates how to do so: 
<jbpm-configuration>
    ...
    <string name="jbpm.mail.bcc.address" value="bcc@mycompany.com" />
</jbpm-configuration>

12.3.3.  Address Resolving

Throughout the Business Process Manager, actors are referenced by actorIds. These are strings that serves to identify process participants. An address resolver translates actorIds into e-mail addresses.
Use the attribute actors to apply address resolving. Conversely, use the to attribute if adding addresses directly as it will not run apply address resolving.
Make sure the address resolver implements the following interface: 
public interface AddressResolver extends Serializable {
	Object resolveAddress(String actorId);
}
An address resolver will return one of the following three types: a string, a collection of strings or an array of strings. (Strings must always represent e-mail addresses for the given actorId.)
Ensure that the address resolver implementation is a bean. This bean must be configured in the jbpm.cfg.xml file with name jbpm.mail.address.resolver, as per this example: 
<jbpm-configuration>
    <bean name='jbpm.mail.address.resolver' 
        class='org.jbpm.identity.mail.IdentityAddressResolver' 
        singleton='true' />
</jbpm-configuration>
The Business Process Manager's identity component includes an address resolver. This address resolver will look for the given actorId's user. If the user exists, their e-mail address will be returned. If not, null will be returned.

Note

To learn more about the identity component, read Section 8.11, “ The Identity Component ”.

12.4.  E-Mail Templates

Instead of using the processdefinition.xml file to specify e-mails, one can use a template. In this case, each of the fields can still be overwritten by processdefinition.xml. Specify a templates like this: 
<mail-templates>
    <variable name="BaseTaskListURL"
        value="http://localhost:8080/jbpm/task?id=" />

    <mail-template name='task-assign'>
        <actors>#{taskInstance.actorId}</actors>
        <subject>Task '#{taskInstance.name}'</subject>
        <text><![CDATA[Hi,
Task '#{taskInstance.name}' has been assigned to you.
Go for it: #{BaseTaskListURL}#{taskInstance.id}
Thanks.
---powered by JBoss jBPM---]]></text>
    </mail-template>

    <mail-template name='task-reminder'>
        <actors>#{taskInstance.actorId}</actors>
        <subject>Task '#{taskInstance.name}' !</subject>
        <text><![CDATA[Hey,
Don't forget about #{BaseTaskListURL}#{taskInstance.id} 
Get going !
---powered by JBoss jBPM---]]></text>
    </mail-template>

</mail-templates>
Extra variables can be defined in the mail templates and these will be available in the expressions.
Configure the resource that contains the templates via the jbpm.cfg.xml like this: 
<jbpm-configuration>
  <string name="resource.mail.templates" value="jbpm.mail.templates.xml" />
</jbpm-configuration>

12.5.  Mail Server Configuration

Configure the mail server by setting the jbpm.mail.smtp.host property in the jbpm.cfg.xml file, as per this example code: 
<jbpm-configuration>
    <string name="jbpm.mail.smtp.host" value="localhost" />
</jbpm-configuration>
Alternatively, when more properties need to be specified, give a resource reference to a properties file in this way: 
<jbpm-configuration>
   <string name='resource.mail.properties' value='jbpm.mail.properties' />
</jbpm-configuration>

12.6.  Email Authentication

12.6.1.  Email authentication configuration

The following settings can be used to enable (SMTP) authentication when sending email.

Table 12.1. jBPM mail authentication properties

Property Type Description
jbpm.mail.user
string
The email address of the user
jbpm.mail.password
string
The password for that email address
jbpm.mail.smtp.starttls
boolean
Whether or not to use the STARTTLS protocol with the SMTP server
jbpm.mail.smtp.auth
boolean
Whether or not to use the SMTP authentication protocol
jbpm.mail.debug
boolean
Whether or not to set the javax.mail.Session instance to debug mode

12.6.2.  Email authentication logic

The following logic is applied with regards to the above properties:
If neither the jbpm.mail.user nor the jbpm.mail.password property is set, authentication is not used regardless of other settings set.
If the jbpm.mail.user property is set, then the following is done:
  • The mail.smtp.submitter property is set with the value of the jbpm.mail.user property
  • The jbpm engine will try to login into the smtp server when sending email.
If the jbpm.mail.user property and the jbpm.mail.password property are set, then the following is done:
  • Everything that is done when at least the jbpm.mail.user is set, is also done in this case
  • The mail.smtp.auth property is set to true, regardless of the value of the jbpm.mail.smtp.auth property

12.7.  "From" Address Configuration

The default value for the From address field jbpm@noreply. Configure it via the jbpm.xfg.xml file with key jbpm.mail.from.address like this: 
<jbpm-configuration>
    <string name='jbpm.mail.from.address' value='jbpm@yourcompany.com' />
</jbpm-configuration>

12.8.  Customizing E-Mail Support

All of the Business Process Manager's e-mail support is centralized in one class, namely org.jbpm.mail.Mail. This class is an ActionHandler implementation. Whenever an e-mail is specified in the process XML, a delegation to the mail class will result. It is possible to inherit from the mail class and customize certain behavior for specific needs. To configure a class to be used for mail delegations, specify a jbpm.mail.class.name configuration string in the jbpm.cfg.xml like this: 
<jbpm-configuration>
  <string name='jbpm.mail.class.name'
  value='com.your.specific.CustomMail' />
</jbpm-configuration>
The customized mail class will be read during parsing. Actions will be configured in the process that reference the configured (or the default) mail classname. Hence, if the property is changed, all the processes that were already deployed will still refer to the old mail classname. Alter them simply by sending an update statement directed at the jBPM database.
This chapter has provided detailed information on how to configure various e-mail settings. You can now practice configuring your own environment