```
public interface Activator
```
An activator is a special type which allows a provider to be plugged into the system by dropping a jar file in with the kernel and adding in a hook in the configuration file. Activators are started after the initial classes and the service manager have already been started. All classes which implement this must have a public empty constructor (takes no parameters) (e.g. public MyClass() {} )
If you want the system to execute your class then you must list it in the DSpace configuration with the fully qualified classpath (NOTE that the xxx can be anything as long as it is unique):
activator.xxx = org.dspace.MyClass

start(ServiceManager) will be called after the class is created during kernel startup. Developers should create their providers/plugins/etc. in this method and use the registration methods in the ServiceManager to register them. stop(ServiceManager) will be called when the kernel shuts down. Perform any cleanup/shutdown actions you like during this phase (unregistering your services here is a good idea).

This is modeled after the OSGi BundleActivator.

There is another type of activator used in DSpace but it is configured via the configuration service only. The class activator is configured by creating a config property like this (NOTE that the xxx can be anything as long as it is unique):
activator.class.xxx = org.dspace.MyClass;org.dspace.MyServiceName;constructor
Unlike the normal activators, these are started up when the kernel core services start and thus can actually be accessed from the service manager and referenced in providers and plugins.

Author:

Aaron Zeckoski (azeckoski @ gmail.com)

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`void`	`start(ServiceManager serviceManager)`	This is called when the service manager is starting this activator.
`void`	`stop(ServiceManager serviceManager)`	This is called when the service manager is shutting down this activator.

- Method Detail
  - start
```
void start(ServiceManager serviceManager)
```
    This is called when the service manager is starting this activator. It is only called once. It will be called after the core services are started. The ClassLoader used will be the one that this class is associated with to ensure all dependencies are available.
    This method should be used to startup and register services in most cases but it can be used to simply perform some system startup actions if desired.
    Exceptions thrown out of this method will not cause the system startup to fail.
    
    Parameters:
    
    serviceManager - the current system service manager
  - stop
```
void stop(ServiceManager serviceManager)
```
    This is called when the service manager is shutting down this activator. It is only called once. It will be called before the core services are stopped. The ClassLoader used will be the one that this class is associated with to ensure all dependencies are available.
    This method should be used to shutdown and unregister services in most cases but it can be used to simply perform some system shutdown actions if desired.
    Exceptions thrown out of this method will not cause the system shutdown to fail.
    WARNING: this can hang the shutdown by performing operations that take a long long time or are deadlocked. The developer is expected to ensure this does not happen.
    
    Parameters:
    
    serviceManager - the current system service manager

Interface Activator

Method Summary

Method Detail

start

stop