io.aalam.common

Interface Callbacks

public interface Callbacks

Every application using this library will have to implement this class and return an object of that class from it's entry point.

Field Summary

Fields

Modifier and Type	Field and Description
static int	STATE_MIGRATE This state means the application is getting upgraded and this is the first call to the upgradation process.
static int	STATE_POST_MIGRATE This state means the application is getting upgraded and this is the final stage of the upgradation process.
static int	STATE_RESTARTED This state means the application is restarted after recovering from a crash.
static int	STATE_STARTED When an application is started in this state, it means the application is started afresh.
static int	STATE_VALIDATION This is called mostly from the packager which does the package validation.

Method Summary

Modifier and Type	Method and Description
void	cleanup() This callback will invoked when the application is asked to quit.
void	migrate(String fromVersion) This callback is invoked as the first step for updating an application.
void	migrateCompleted() This callback is invoked on the new process that is running on state STATE_POST_MIGRATE.
void	routes(Mapper mapper) This method is where the URL registration have to be done.

Field Detail

STATE_STARTED

static final int STATE_STARTED

When an application is started in this state, it means the application is started afresh.

See Also:

Constant Field Values

STATE_RESTARTED

static final int STATE_RESTARTED

This state means the application is restarted after recovering from a crash. This state is not supported and is reserved for future use.

See Also:

Constant Field Values

STATE_MIGRATE

static final int STATE_MIGRATE

This state means the application is getting upgraded and this is the first call to the upgradation process. Any initialization needed for the migration processs can be done here. In this state the application will not listen on any requests from the client.

See Also:

Constant Field Values

STATE_POST_MIGRATE

static final int STATE_POST_MIGRATE

This state means the application is getting upgraded and this is the final stage of the upgradation process. This state is equivalent to STATE_STARTED except that this signifies that the application has just now completed migrating its data from the old app.

See Also:

Constant Field Values

STATE_VALIDATION

static final int STATE_VALIDATION

This is called mostly from the packager which does the package validation. No initialization should be done here. This state expects only the routing parameters from the entry-point, so the initialization will fail. Right now this state is not used by the packager. This is reserved for future use.

See Also:

Constant Field Values

Method Detail

routes

void routes(Mapper mapper)

This method is where the URL registration have to be done. This callback will be invoked on all application states except STATE_MIGRATE.

Parameters:

mapper - The mapper object to which the URL should be connected to

See Also:

Mapper

cleanup

void cleanup()

This callback will invoked when the application is asked to quit. When it is invoked, the application will not serve any incoming requests, however it will wait till the application finishes serving earlier requests. This callback should close up any persistent connections like websockets. If the cleanup is proper, the application will quit imediately after serving the last HTTP request, else the application will be terminated after some time.

migrate

void migrate(String fromVersion)

This callback is invoked as the first step for updating an application. Any data migrations from the older version should be done here. While migrating, the older application will still be running, so the migration should not affect the older application.

Parameters:

fromVersion - The older version from which the new version is migrating from

migrateCompleted

void migrateCompleted()

This callback is invoked on the new process that is running on state STATE_POST_MIGRATE. This is invoked as soon as the old process quits after serving all pending connections.