com.github.oxo42.stateless4j

Class StateMachine<S,T>

java.lang.Object

com.github.oxo42.stateless4j.StateMachine<S,T>

Type Parameters:

S - The type used to represent the states

T - The type used to represent the triggers that cause state transitions

public class StateMachine<S,T>
extends java.lang.Object

Models behaviour as transitions between a finite set of states

Field Summary

Fields

Modifier and Type	Field and Description
protected StateMachineConfig<S,T>	config
protected Func<S>	stateAccessor
protected Action1<S>	stateMutator
protected Action2<S,T>	unhandledTriggerAction

Constructor Summary

Constructors

Constructor and Description
StateMachine(S intialState) Construct a state machine
StateMachine(S initialState, Func<S> stateAccessor, Action1<S> stateMutator, StateMachineConfig<S,T> config) Construct a state machine with external state storage.
StateMachine(S initialState, StateMachineConfig<S,T> config) Construct a state machine

Method Summary

Modifier and Type	Method and Description
boolean	canFire(T trigger) Returns true if trigger can be fired in the current state
StateConfiguration<S,T>	configure(S state)
void	fire(T trigger) Transition from the current state via the specified trigger.
<TArg0> void	fire(TriggerWithParameters1<TArg0,S,T> trigger, TArg0 arg0) Transition from the current state via the specified trigger.
<TArg0,TArg1> void	fire(TriggerWithParameters2<TArg0,TArg1,S,T> trigger, TArg0 arg0, TArg1 arg1) Transition from the current state via the specified trigger.
<TArg0,TArg1,TArg2> void	fire(TriggerWithParameters3<TArg0,TArg1,TArg2,S,T> trigger, TArg0 arg0, TArg1 arg1, TArg2 arg2) Transition from the current state via the specified trigger.
java.util.List<T>	getPermittedTriggers() The currently-permissible trigger values
S	getState() The current state
boolean	isInState(S state) Determine if the state machine is in the supplied state
void	onUnhandledTrigger(Action2<S,T> unhandledTriggerAction) Override the default behaviour of throwing an exception when an unhandled trigger is fired
protected void	publicFire(T trigger, java.lang.Object... args)
java.lang.String	toString() A human-readable representation of the state machine

Methods inherited from class java.lang.Object

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

Field Detail

config

protected final StateMachineConfig<S,T> config

stateAccessor

protected final Func<S> stateAccessor

stateMutator

protected final Action1<S> stateMutator

unhandledTriggerAction

protected Action2<S,T> unhandledTriggerAction

Constructor Detail

StateMachine

public StateMachine(S intialState)

Construct a state machine

Parameters:

intialState - The initial state

StateMachine

public StateMachine(S initialState,
                    StateMachineConfig<S,T> config)

Construct a state machine

Parameters:

initialState - The initial state

config - State machine configuration

StateMachine

public StateMachine(S initialState,
                    Func<S> stateAccessor,
                    Action1<S> stateMutator,
                    StateMachineConfig<S,T> config)

Construct a state machine with external state storage.

Parameters:

initialState - The initial state

stateAccessor - State accessor

stateMutator - State mutator

Method Detail

configure

public StateConfiguration<S,T> configure(S state)

getState

public S getState()

The current state

Returns:

The current state

getPermittedTriggers

public java.util.List<T> getPermittedTriggers()

The currently-permissible trigger values

Returns:

The currently-permissible trigger values

fire

public void fire(T trigger)

Transition from the current state via the specified trigger. The target state is determined by the configuration of the current state. Actions associated with leaving the current state and entering the new one will be invoked

Parameters:

trigger - The trigger to fire

fire

public <TArg0> void fire(TriggerWithParameters1<TArg0,S,T> trigger,
                         TArg0 arg0)

Transition from the current state via the specified trigger. The target state is determined by the configuration of the current state. Actions associated with leaving the current state and entering the new one will be invoked.

Type Parameters:

TArg0 - Type of the first trigger argument

Parameters:

trigger - The trigger to fire

arg0 - The first argument

fire

public <TArg0,TArg1> void fire(TriggerWithParameters2<TArg0,TArg1,S,T> trigger,
                               TArg0 arg0,
                               TArg1 arg1)

Transition from the current state via the specified trigger. The target state is determined by the configuration of the current state. Actions associated with leaving the current state and entering the new one will be invoked.

Type Parameters:

TArg0 - Type of the first trigger argument

TArg1 - Type of the second trigger argument

Parameters:

trigger - The trigger to fire

arg0 - The first argument

arg1 - The second argument

fire

public <TArg0,TArg1,TArg2> void fire(TriggerWithParameters3<TArg0,TArg1,TArg2,S,T> trigger,
                                     TArg0 arg0,
                                     TArg1 arg1,
                                     TArg2 arg2)

Transition from the current state via the specified trigger. The target state is determined by the configuration of the current state. Actions associated with leaving the current state and entering the new one will be invoked.

Type Parameters:

TArg0 - Type of the first trigger argument

TArg1 - Type of the second trigger argument

TArg2 - Type of the third trigger argument

Parameters:

trigger - The trigger to fire

arg0 - The first argument

arg1 - The second argument

arg2 - The third argument

publicFire

protected void publicFire(T trigger,
                          java.lang.Object... args)

onUnhandledTrigger

public void onUnhandledTrigger(Action2<S,T> unhandledTriggerAction)

Override the default behaviour of throwing an exception when an unhandled trigger is fired

Parameters:

unhandledTriggerAction - An action to call when an unhandled trigger is fired

isInState

public boolean isInState(S state)

Determine if the state machine is in the supplied state

Parameters:

state - The state to test for

Returns:

True if the current state is equal to, or a substate of, the supplied state

canFire

public boolean canFire(T trigger)

Returns true if trigger can be fired in the current state

Parameters:

trigger - Trigger to test

Returns:

True if the trigger can be fired, false otherwise

toString

public java.lang.String toString()

A human-readable representation of the state machine

Overrides:

toString in class java.lang.Object

Returns:

A description of the current state and permitted triggers