In eXo Platform, whenever an action occurs (for example, login/logout, content creation/modification), a corresponding event is sent to Listener Service that dispatches the notification to its listeners. Listeners then can perform whatever action they want when receiving an event. See Listener Service events for more details.
In this section, you will have opportunity to learn about Organization listeners, how to write and pack them in a .jar file,
then deploy them into eXo Platform based on the extension mechanism of eXo Platform.
To write a new organization listener, you first need to know about Organization Service that provides a mechanism to receive notifications when:
A user is created, deleted, modified, enabled or disabled.
A group is created, deleted or modified.
A membership is created or removed.
This mechanism is very useful to cascade some actions when the organization model is modified. For example, it is currently used to initialize the personal portal pages or to create drives and personal areas.
In term of working mechanism of Organization listeners, it is quite similar to that of Listener Service. See Understanding the Listener Service for how it works and how to configure a listener in general.
Writing Organization listeners
Create a JAR project, named my-event-listeners for example, with the following structure:
Declare the dependencies needed for your own listeners in the
pom.xmlfile (you can go to eXo Platform repository to check the artifact versions). Thepom.xmlfile now looks like:<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>exo.userevent.listener</groupId>
<artifactId>my-event-listeners</artifactId>
<packaging>jar</packaging>
<version>1.0-SNAPSHOT</version>
<name>maven</name>
<url>http://maven.apache.org</url>
<dependencies>
<dependency>
<groupId>org.exoplatform.core</groupId>
<artifactId>exo.core.component.organization.api</artifactId>
<version>2.6.0-GA</version>
</dependency>
<dependency>
<groupId>javax.jcr</groupId>
<artifactId>jcr</artifactId>
<version>2.0</version>
</dependency>
<dependency>
<groupId>javax.annotation</groupId>
<artifactId>jsr250-api</artifactId>
<version>1.0</version>
</dependency>
</dependencies>
</project>
Implement your own listeners by extending some existing listener classes in
src/main/java/org/exoplatform/listener. These classes define hooks that are invoked before or after operations are performed on the organization model.UserEventListener:
To listen to user changes, you need to extend
org.exoplatform.services.organization.UserEventListenerinMyUserListener.java.package org.exoplatform.listener;
import javax.jcr.Node;
import javax.jcr.Session;
import org.exoplatform.services.organization.User;
import org.exoplatform.services.organization.UserEventListener;
public class MyUserListener extends UserEventListener {
public void preSave(User user, boolean isNew) throws Exception {
//do something - customer code is here
System.out.println("Before user is added into database");
}
public void preDelete(User user) throws Exception {
//do something - customer code is here
System.out.println("Before user is deleted from database");
}
public void postSave(User user, boolean isNew) throws Exception {
//do something - customer code is here
System.out.println("After user is added into database");
}
public void postDelete(User user) throws Exception {
//do something - customer code is here
System.out.println("After user is deleted from database");
}
}See sample here.
GroupEventListener:
To listen to group changes, you need to extend
org.exoplatform.services.organization.GroupEventListenerinMyGroupListener.java.package org.exoplatform.listener;
import javax.jcr.Session;
import org.exoplatform.services.organization.Group;
import org.exoplatform.services.organization.GroupEventListener;
public class MyGroupListener extends GroupEventListener {
public void preSave(Group group, boolean isNew) throws Exception {
//do something - customer code is here
System.out.println("Before group is added into database");
}
public void preDelete(Group group) throws Exception {
//do something - customer code is here
System.out.println("Before group is removed from database");
}
public void postSave(Group group, boolean isNew) throws Exception {
//do something - customer code is here
System.out.println("After group is added into database");
}
public void postDelete(Group group) throws Exception {
//do something - customer code is here
System.out.println("After group is removed from database");
}
}See sample here.
MembershipEventListener:
To listen to membership changes, you need to extend
org.exoplatform.services.organization.MembershipEventListenerinMyMembershipListener.java.package org.exoplatform.listener;
import javax.jcr.Session;
import org.exoplatform.services.organization.Membership;
import org.exoplatform.services.organization.MembershipEventListener;
public class MyMembershipListener extends MembershipEventListener {
public void preSave(Membership m, boolean isNew) throws Exception{
//do something - customer code is here
System.out.println("Before membership is added into database");
}
public void postSave(Membership m, boolean isNew) throws Exception{
//do something - customer code is here
System.out.println("After membership is added into database");
}
public void preDelete(Membership m) throws Exception{
//do something - customer code is here
System.out.println("Before membership is removed from database");
}
public void postDelete(Membership m) throws Exception{
//do something - customer code is here
System.out.println("After membership is removed from database");
}
}See sample here.
Register your own listeners in
configuration.xml. Registering the listeners is then achieved by using the ExoContainer plugin mechanism. See Service configuration for beginners for more information.To effectively register Organization listeners, you simply need to use the addListenerPlugin set-method.
<?xml version="1.0" encoding="ISO-8859-1"?>
<configuration
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.exoplatform.org/xml/ns/kernel_1_2.xsd http://www.exoplatform.org/xml/ns/kernel_1_2.xsd"
xmlns="http://www.exoplatform.org/xml/ns/kernel_1_2.xsd">
<external-component-plugins>
<target-component>org.exoplatform.services.organization.OrganizationService</target-component>
<component-plugin>
<name>my.new.user.event.listener</name>
<set-method>addListenerPlugin</set-method>
<type>org.exoplatform.listener.MyUserListener</type>
<description>description</description>
</component-plugin>
<component-plugin>
<name>my.new.group.event.listener</name>
<set-method>addListenerPlugin</set-method>
<type>org.exoplatform.listener.MyGroupListener</type>
<description>description</description>
</component-plugin>
<component-plugin>
<name>my.membership.group.event.listener</name>
<set-method>addListenerPlugin</set-method>
<type>org.exoplatform.listener.MyMembershipListener</type>
<description>description</description>
</component-plugin>
</external-component-plugins>
</configuration>
See sample here.
Build your JAR project, then deploy the
.jarfile (intarget/) under eXo Platform.$PLATFORM_TOMCAT_HOME/lib(in Tomcat).$PLATFORM_JBOSS_HOME/standalone/deployments/platform.ear!/lib(in JBoss).
Start eXo Platform. Your own listeners are now ready for testing.
To check if either of your own listeners takes effect, try the case when creating a new account by selecting
→ → . Once you have clicked , two strings will be printed to the console:
"Before user is added into database" and "After user is added into database", as defined in MyUserListener.java.