sPFFramework/src/main/java/it/polimi/spf/framework/proximity/SPFRemoteInstance.java
public final void sendNotification(String uniqueIdentifier, SPFActionSendNotification action) {
        if (uniqueIdentifier == null || action == null) {
            throw new NullPointerException();
        }

        String actionJSON = action.toJSON();
        sendNotification(uniqueIdentifier, actionJSON);
    }
public final void sendNotification(String uniqueIdentifier, SPFActionSendNotification action) {
        if (uniqueIdentifier == null || action == null) {
            throw new NullPointerException();
        }

        String actionJSON = action.toJSON();
        sendNotification(uniqueIdentifier, actionJSON);
    }
Sends a notification to the remote SPF instance.

@param uniqueIdentifier - the identifier of the sender.
@param action           - the notification action.