Class Handler

The handling of a request happens in 6 stages. A visualization of these stages can be found here:

1. At first the session (see Session) is identified and the client context is initialized (see RequestLocal and ServerMode). This is done automatically by the class HttpServer.
2. In a second step the handler which is responsible for handling the request is identified. This is done by the HandlerDispatcher, which creates an instance of the identified handler class.
3. The handler checks whether the current session is allowed to call this handler. This is done by implementing the method checkAccess().
4. The handler executes business logic, which in most cases involves the manipulation of the state of Assets. This is done by implementing the method doBusinessLogic(). This method returns an object of type Station, which is responsible for the next step.
5. The Station either forwards the request to another Handler (this is done by Lines, step 6a in the figure above) or sends an answer page back (using a subclass of AnswerStation, step 6b in the figure above).

A typical handler will have the following attributes:

Field Summary

Constructor Summary

Method Summary

Field Detail

public static final ParameterizedMessage DELETE_CONFIRMATION

public static final Message protectedActionError

public static final String GET_STATIONS

public static SimpleDateFormat withoutYearDateFormat

public static final SimpleDateFormat withYearDateFormat

public static final Message timeDifferenceLessOneMinute

public static final Message timeDifferenceMinutesPostfix

public static final Message timeDifferenceOneHour

public static final Message timeDifferenceHoursPostfix

public static int secondsOfADay

public static final String PARAMETER_TAG

Constructor Detail

public Handler()

Method Detail

public final Response getResponse()
                           throws Throwable

protected void afterStationHook()

public void checkAccessExtensions()

public abstract Station doBusinessLogic()

public void checkAccess()

public static String getDateTime(Date date)

protected Station extension(Station station)

protected Line getDefaultGoToEditStation(Entity entity)

public void goToParentBreadCrumb(Forwarder f)

public Message getBreadcrumbLabel()

public Message getTargetLabel()

public static Station createJSONSuccessStation()

public static Station createJSONSuccessStation(Map keyValues)

public static Station createJSONErrorStation()

public static Station createJSONErrorStation(String errorMessage)

public static Station createJSONErrorStation(String errorMessage,
                                             Map additionalParameters)

public boolean hideForAnonymousUsers()

public static NameValue[] getTagNameValues(String[] tags,
                                         NameValue[] params)