Deleting a file through programming
You can delete a file from an existing application through the administrative console, the wsadmin tool, or programming. Use this example to delete a file through programming.
Before you begin
Before you can delete a file from an application on WebSphere® Application Server, you must install the application.
About this task
Perform the following tasks to delete a file through programming.
Procedure
- Connect to WebSphere Application Server.
- Create the application management proxy.
- Create the notification filter for listening to events.
- Add the listener.
- Delete the file from the application.
- Wait for some timeout so that the program does not end.
- Listen to Java Management Extensions (JMX) notifications to understand completion of the operation.
- When the file is deleted from the application, remove the listener and quit.
Results
Example
The following example shows how to delete a file based on the previous steps. Some statements are split on multiple lines for printing purposes.
//Inputs:
//fileURI specifies a URI that gives the target location of the file. The URI
// provides the location of the new module after installation. The URI is
// relative to the application URL.
//appName specifies the name of the application.
String fileURI = "Increment.jar/com/acme/Foo.class";
String appName = "MyApp";
//Get the administrative client to connect to
//WebSphere Application Server.
AdminClient client = ...;
//Create the application management proxy.
AppManagement proxy = AppManagementProxy. getJMXProxyForClient (client);
//Create the notification filter.
NotificationFilterSupport myFilter = new NotificationFilterSupport();
myFilter.enableType (NotificationConstants.TYPE_APPMANAGEMENT);
//Add the listener.
NotificationListener listener = new AListener(_soapClient, myFilter,
"Install: " + appName, AppNotification.UPDATE);
//Update the existing application, MyApp, by deleting the file.
Hashtable options = new Hashtable();
options.put (AppConstants.APPDEPL_LOCALE, Locale.getDefault());
options.put (AppConstants.APPUPDATE_CONTENTTYPE, AppConstants.APPUPDATE_CONTENT_FILE);
proxy.updateApplication ( appName,
fileURI,
null,
AppConstants.APPUPDATE_DELETE,
options,
null);
// Wait for some timeout. The installation Application Programming Interface (API) is
// asynchronous and so returns immediately.
// If the program does not wait here, the program ends.
Thread.sleep(300000); // Wait so that the program does not end.
}
catch (Exception e) {
e.printStackTrace();
}
}
}
// Specify the Java Management Extensions (JMX) notification listener for JMX events.
class AListener implements NotificationListener
{
AdminClient _soapClient;
NotificationFilterSupport myFilter;
Object handback;
ObjectName on;
String eventTypeToCheck;
public AListener(AdminClient cl, NotificationFilterSupport fl,
Object h, String eType) throws Exception
{
_soapClient = cl;
myFilter = fl;
handback = h;
eventTypeToCheck = eType;
Iterator iter = _soapClient.queryNames (new ObjectName(
"WebSphere:type=AppManagement,*"), null).iterator();
on = (ObjectName)iter.next();
System.out.println ("ObjectName: " + on);
_soapClient.addNotificationListener (on, this, myFilter, handback);
}
public void handleNotification (Notification notf, Object handback)
{
AppNotification ev = (AppNotification) notf.getUserData();
System.out.println ("!! JMX event Recd: (handback obj= " + handback+ "): " + ev);
//Once the installation is done, remove the listener and quit
if (ev.taskName.equals (eventTypeToCheck) &&
(ev.taskStatus.equals (AppNotification.STATUS_COMPLETED) ||
ev.taskStatus.equals (AppNotification.STATUS_FAILED)))
{
try
{
_soapClient.removeNotificationListener (on, this);
}
catch (Throwable th)
{
System.out.println ("Error removing listener: " + th);
}
System.exit (0);
}
}
}