Package net.officefloor.plugin.managedobject.poll

Class StatePoller<S,F extends java.lang.Enum<F>>

java.lang.Object

net.officefloor.plugin.managedobject.poll.StatePoller<S,F>

public class StatePoller<S,F extends java.lang.Enum<F>>
extends java.lang.Object

Provides polling within a ManagedObjectSource to keep particular state up to date.

Polling is undertaken by invoking a ProcessState from the ManagedObjectExecuteContext of the ManagedObjectSource to load the StatePollContext with the next state value. Also, means to provide failures that are logged.

This is a convenient and efficient means to make keeping state of a ManagedObjectSource up to date (without having to manage the ManagedObjectExecuteContext or separate Timer that needs to be coordinated with the OfficeFloorListener).

Example use would be keeping JWT keys up to date.

Author:

Daniel Sagenschneider

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	StatePoller.Builder<S,F extends java.lang.Enum<F>>	Builder for the StatePoller.
static interface	StatePoller.Initialiser<S>	Initialiser for polling state.
static interface	StatePoller.Poller<S>	Custom poller.

Method Summary

Modifier and Type	Method	Description
static <S> StatePoller.Builder<S,Indexed>	builder(java.lang.Class<S> stateType, Clock<java.lang.Long> clock, int flowIndex, ManagedObjectExecuteContext<Indexed> executeContext, java.util.function.Function<StatePollContext<S>,ManagedObject> managedObjectFactory)	Creates a StatePoller.Builder for Flow index.
static <S,F extends java.lang.Enum<F>> StatePoller.Builder<S,F>	builder(java.lang.Class<S> stateType, Clock<java.lang.Long> clock, F flowKey, ManagedObjectExecuteContext<F> executeContext, java.util.function.Function<StatePollContext<S>,ManagedObject> managedObjectFactory)	Creates a StatePoller.Builder for Flow key.
static <S> StatePoller.Builder<S,None>	builder(java.lang.Class<S> stateType, Clock<java.lang.Long> clock, StatePoller.Initialiser<S> initialiser, StatePoller.Poller<S> poller)	Creates a StatePoller.Builder for custom StatePoller.Poller.
void	clear()	Allows clearing the state.
S	getState(long timeout, java.util.concurrent.TimeUnit unit)	Obtains the current state.
S	getStateNow()	Obtains the current state or null if not yet initialised.
void	poll()	Manually trigger poll.
static <S,F extends java.lang.Enum<F>> StatePoller<S,F>	state(S state)	Creates an initialised StatePoller that does not poll.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Detail

state

public static <S,F extends java.lang.Enum<F>> StatePoller<S,F> state(S state)

Creates an initialised StatePoller that does not poll.

This is useful if state is loaded without needing polling. This allows the ManagedObjectSource to poll in some cases and load from configuration in others. This then allows using StatePoller for single interface to state.

Type Parameters:

S - State type.

F - Flow Enum.

Parameters:

state - State.

Returns:

StatePoller initialised with state.

builder

public static <S,F extends java.lang.Enum<F>> StatePoller.Builder<S,F> builder(java.lang.Class<S> stateType,
                                                                                           Clock<java.lang.Long> clock,
                                                                                           F flowKey,
                                                                                           ManagedObjectExecuteContext<F> executeContext,
                                                                                           java.util.function.Function<StatePollContext<S>,ManagedObject> managedObjectFactory)

Creates a StatePoller.Builder for Flow key.

Parameters:

stateType - State type.

clock - Clock.

flowKey - Flow key to use to invoke the polling ProcessState from the ManagedObjectExecuteContext.

executeContext - ManagedObjectExecuteContext.

managedObjectFactory - Factory to create the ManagedObject.

Returns:

StatePoller.Builder.

builder

public static <S> StatePoller.Builder<S,Indexed> builder(java.lang.Class<S> stateType,
                                                               Clock<java.lang.Long> clock,
                                                               int flowIndex,
                                                               ManagedObjectExecuteContext<Indexed> executeContext,
                                                               java.util.function.Function<StatePollContext<S>,ManagedObject> managedObjectFactory)

Creates a StatePoller.Builder for Flow index.

Parameters:

stateType - State type.

clock - Clock.

flowIndex - Flow index to use to invoke the polling ProcessState from the ManagedObjectExecuteContext.

executeContext - ManagedObjectExecuteContext.

managedObjectFactory - Factory to create the ManagedObject.

Returns:

StatePoller.Builder.

builder

public static <S> StatePoller.Builder<S,None> builder(java.lang.Class<S> stateType,
                                                            Clock<java.lang.Long> clock,
                                                            StatePoller.Initialiser<S> initialiser,
                                                            StatePoller.Poller<S> poller)

Creates a StatePoller.Builder for custom StatePoller.Poller.

This allows for higher level types that rely on but do not expose the ManagedObjectSource to use this StatePoller.

Parameters:

stateType - State type.

clock - Clock.

initialiser - StatePoller.Initialiser.

poller - StatePoller.Poller.

Returns:

StatePoller.Builder.

getStateNow

public S getStateNow()

Obtains the current state or null if not yet initialised.

This is a non-blocking method to enable obtaining the current state immediately. Useful if state is optional or has defaults, so does not need to wait to be initialised with first poll.

Returns:

Current state or null if not yet initialised.

getState

public S getState(long timeout,
                  java.util.concurrent.TimeUnit unit)
           throws java.util.concurrent.TimeoutException

Obtains the current state.

Parameters:

timeout - The maximum time to wait.

unit - The time unit of the timeout.

Returns:

State.

Throws:

java.util.concurrent.TimeoutException - If times out waiting on the initial state.

poll

public void poll()

Manually trigger poll.

clear

public void clear()

Allows clearing the state.