envoy/server/src/main/java/envoy/server/processors/UserStatusChangeProcessor.java

package envoy.server.processors;

import java.util.logging.Logger;

import envoy.data.User.UserStatus;
import envoy.event.UserStatusChange;
import envoy.util.EnvoyLog;

import envoy.server.data.*;
import envoy.server.net.ObjectWriteProxy;

/**
 * This processor handles incoming {@link UserStatusChange}.
 *
 * @author Leon Hofmeister
 * @since Envoy Server Standalone v0.1-alpha
 */
public final class UserStatusChangeProcessor implements ObjectProcessor<UserStatusChange> {

	private static ObjectWriteProxy writeProxy;

	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
	private static final Logger				logger				=
		EnvoyLog.getLogger(UserStatusChangeProcessor.class);

	@Override
	public void process(UserStatusChange input, long socketID, ObjectWriteProxy writeProxy) {
		// new status should not equal old status
		if (input.get().equals(persistenceManager.getUserByID(input.getID()).getStatus())) {
			logger.warning("Received an unnecessary UserStatusChange");
			return;
		}
		updateUserStatus(persistenceManager.getUserByID(input.getID()), input.get());
	}

	/**
	 * Sets the {@link UserStatus} for a given user. Both offline contacts and currently online
	 * contacts are notified.
	 *
	 * @param user      the user whose status has changed
	 * @param newStatus the new status of that user
	 * @since Envoy Server Standalone v0.1-alpha
	 */

	public static void updateUserStatus(User user, UserStatus newStatus) {
		user.setStatus(newStatus);

		// Handling for newly logged in clients
		persistenceManager.updateContact(user);

		// Handling for contacts that are already online
		writeProxy.writeToOnlineContacts(user.getContacts(),
			new UserStatusChange(user.getID(), user.getStatus()));
	}

	/**
	 * This method is only called by the LoginCredentialProcessor because every user needs to login
	 * (open a socket) before changing his status. Needed to ensure propagation of events because an
	 * uninitialized writeProxy would cause problems.
	 *
	 * @param writeProxy the writeProxy that is used to send objects back to clients
	 * @since Envoy Server Standalone v0.1-alpha
	 */
	public static void setWriteProxy(ObjectWriteProxy writeProxy) {
		UserStatusChangeProcessor.writeProxy = writeProxy;
	}
	// TODO may cause an problem if two clients log in at the same time.
	// Change Needed.
}