Taking Advantage of Mule Lifecycle
Cloud connectors can be fully aware of Mule’s lifecycle without implementing any Mule specific interface. There is one method annotation for each of the four phases of Mule lifecycle. If a method is annotated with one of these annotations it will be invoked during the Mule lifecycle phase that annotation represents.
Each annotation can be applied to one method at the most.
Initialise phase
To have a method invoked during the Start phase it needs to be annotated with @PostConstruct. At most only one method can have the @PostConstruct annotation.
import org.mule.api.annotations.Module;
import javax.annotation.PostConstruct;
@Module(name = "myconnector")
public class MyConnector {
...
@PostConstruct
public void anyMethodName() {
// your code here
}
...Start phase
To have a method invoked during the Start phase it needs to be annotated with @Start. At most only one method can have the @Start annotation.
import org.mule.api.annotations.Module;
import org.mule.api.annotations.lifecycle.Start;
@Module(name = "myconnector")
public class MyConnector {
...
@Start
public void anyMethodName() {
// your code here
}
...Stop phase
To have a method invoked during the Stop phase it needs to be annotated with @Stop. At most only one method can have the @Stop annotation.
import org.mule.api.annotations.Module;
import org.mule.api.annotations.lifecycle.Stop;
@Module(name = "myconnector")
public class MyConnector {
...
@Stop
public void anyMethodName() {
// your code here
}
...Dispose phase
To have a method invoked during the Dispose phase it needs to be annotated with @PreDestroy. At most only one method can have the @PreDestroy annotation.
import org.mule.api.annotations.Module;
import org.mule.api.annotations.lifecycle.Dispose;
@Module(name = "myconnector")
public class MyConnector {
...
@PreDestroy
public void anyMethodName() {
// your code here
}
...A real life example
The following code fragment is taken from the Twilio Cloud Connector. During the Start phase an instance of the class TwilioClient is created.
package org.mule.module.twilio;
import org.mule.api.annotations.Configurable;
import org.mule.api.annotations.Module;
import org.mule.api.annotations.Processor;
import org.mule.api.annotations.lifecycle.Start;
import org.mule.api.annotations.param.Optional;
import org.mule.api.callback.HttpCallback;
@Module(name = "twilio")
public class TwilioConnector {
/**
* The account sid to be used to connect to Twilio.
*/
@Configurable
private String accountSid;
/**
* The authentication token to be used to connect to Twilio
*/
@Configurable
private String authToken;
private TwilioClient twilioClient;
@Start
public void createTwilioClient() {
twilioClient = new TwilioClient(accountSid, authToken);
}Restrictions
When annotating methods with these lifecycle annotations consider the following:
-
At most one method can be annotated with @PostConstruct
-
At most one method can be annotated with @Start
-
At most one method can be annotated with @Stop
-
At most one method can be annotated with @PreDestroy
-
None of these annotations can be applied to static methods
-
None of these annotations can be applied to non-public methods
-
None of these annotations can be applied to methods that take arguments
-
None of these annotations can be applied to methods that do not return void