Every organization has its own way of implementing and managing the various user roles, names, groups and their memberships.

jBPM provides a flexible way of incorporating one's own identity management component. jBPM includes an optional identity component that can be easily replaced with a company's own identity data store.

An assignee is identified by its ID in jBPM terminology. jBPM has only knowledge about assignee's ids and they are represented as java.lang.String for maximum flexibility.

Implementing Custom Identity Management Component

jBPM code contains a class called "IdentitySessionImpl" which takes care of the identity implementation. By simply overriding this class's methods, one can use its own implementation.

A sample class overriding the default identity class is shown below. Here, a dummy table "demo_identity" is taken as reference, which is present in Hsql Database and contains the following parameters:

The demo class "CustomIdentitySession" is shown below:

public class IdentitySessionImpl implements IdentitySession{

public Group findGroupById(String arg0) {
try
{
List<Group> groups = new ArrayList<Group>();
Group group = null;
Class.forName("org.hsqldb.jdbcDriver");
String url = "jdbc:hsqldb:hsql://localhost:1701";
Connection conn = DriverManager.getConnection(url,"sa","");
Statement stmt = conn.createStatement();
ResultSet rs = stmt.executeQuery("SELECT groupname FROM demo_identity WHERE groupname = '"+arg0+"'");
while(rs.next())
{
group = new GroupImpl(rs.getString("groupname"));
}
return group;
}
catch (Exception e)
{
System.err.println("Got an exception! ");
System.err.println(e.getMessage());
}
return null;
}


public List<Group> findGroupsByUser(String arg0) {
// TODO Auto-generated method stub
try
{
..
ResultSet rs = stmt.executeQuery("SELECT groupname FROM demo_identity WHERE username = '"+arg0+"'");
System.out.println("in my findGroupsByUser");
while(rs.next())
{
group = new GroupImpl(rs.getString(1));
System.out.println(group);
groups.add(group);
}
return groups;
}
catch (Exception e)
.. }


public User findUserById(String arg0) {
try
{
...
ResultSet rs = stmt.executeQuery("SELECT username FROM demo_identity WHERE username = '"+arg0+"'");
System.out.println("in my user impl, method: findUserByid");
while(rs.next())
{
user = new UserImpl(rs.getString(1), "givenName", "familyName");
}
return user;
}
… }

and so on.

In the example above, we are using a simple query using ResultSet to retrieve the user values. You can easily replace this code with the identity management code that you'd want to implement.

Make sure to add your new impl class's absolute address to the jbpm.cfg.xml file, so that this new class is read and implemented when the engine starts.

Implementing Custom Address Resolvers

jBPM sends notifications and triggers by using its default identity management component. However, in case you want to implement your own address resolvers to send notifications, you can do so by simply tweaking the default address resolver class provided by jBPM.

The custom address resolver class uses your custom identity session impl class (as described above) to extract the user information and then resolves the address for him/her.

A simple custom address resolver class is shown below:

package org.addressresolver

import java.util.List;
import javax.mail.Address;
import javax.mail.internet.AddressException;
import javax.mail.internet.InternetAddress;
import org.jbpm.api.identity.Group;
import org.jbpm.api.identity.User;
import org.jbpm.pvm.internal.email.spi.AddressResolver;
import org.jbpm.pvm.internal.env.EnvironmentImpl;
import org.jbpm.pvm.internal.identity.spi.IdentitySession;


public class CustomAddressResolver implements AddressResolver{
public Address resolveAddress(User userName) {
try {
return new InternetAddress(userName.getId()+"@xyz.com");
     } catch (AddressException e) 
     {
System.out.println("In error block of address resolver");
     }
return null;
}


public Address[] resolveAddresses(Group group) {
System.out.println("In custom mail address resolver class: resolve group address");
System.out.println(group.getId());
List<User> users = EnvironmentImpl.getFromCurrent(IdentitySession.class)
                   .findUsersByGroup(group.getId());
int userCount = users.size();
Address[] addresses = new Address[userCount];
for (int i = 0; i < userCount; i++) {
addresses[i] = resolveAddress(users.get(i));
}
return addresses;
}
}

To implement the new resolver, simply add the below in your jbpm.cfg.xml file:

<transaction-context>
<!-- Custom Identity implementation-->
     <object class="org.identity.impl.IdentitySessionImpl"/>
     <object class="org.addressresolver.CustomAddressResolver"/>
     <mail-session>
          <mail-server>
          <session-properties resource="jbpm.mail.properties" />
          <address-resolver class="org.addressresolver.CustomAddressResolver"/>
           </mail-server>
      </mail-session>
</transaction-context>

And there you are! Your custom classes are ready.

You can use them as per your implementation requirements.

Happy learning ..