com.kangirigungi.jstatemachine

Class StateMachineBuilder<StateId,Event>

java.lang.Object

com.kangirigungi.jstatemachine.StateMachineBuilder<StateId,Event>

Type Parameters:

StateId - The type used for referencing states.

Event - The type used for referencing events.

public class StateMachineBuilder<StateId,Event>
extends java.lang.Object

Builder to create state machines. Use this to create instances of IStateMachine. To create a state machine, follow these steps:

1. Create an instance of StateMachineBuilder.
2. Use the get() method to obtain an instance of SubStateMachineBuilder.
3. Use this instance to add states and transitions to the state machine.
4. Each state has an instance of StateBuilder which can be acquired by the SubStateMachineBuilder.addState(Object) method.
5. Each composite state has an instance of CompositeStateBuilder which can be acquired by the SubStateMachineBuilder.addCompositeState(Object) method. Use CompositeStateBuilder.getStateMachineBuilder() to acquire a SubStateMachineBuilder instance for the sub state machine.
6. When all states and transitions of the state machine and all sub statates are created, call create() to create an instance of IStateMachine.

Each state and event has a unique identifier represented by a respective Id types (which are typically enum types, but they can be any type that can be used as a key in a HashMap).

When a transition takes place in a state machine created by this class (by calling the IStateMachine.processEvent(Object) method), the actions are taken place in the following order:

1. The exit action of the old state is called.
2. The transition action is called.
3. The entry action of the new state is called.
4. If the new state is a composite state, the entry action of the initial state of the substate is called (possibly recursively for any subsequent initial states). is called.
5. The current state is changed.

For internal transition no exit or entry actions are called. If an exception is thrown from within a callback, the state is changed. If the exception is thrown after the exit action of the old state is finished, the entry action of that state is called again.

Note: The created class (and the entire library) is not thread-safe. This means that in order to use it from within multiple threads, calls to any methods (typically processEvent) must be synchronized.

Author:

Peter Szabados

Constructor Summary

Constructors

Constructor and Description
StateMachineBuilder()

Method Summary

Methods

Modifier and Type	Method and Description
IStateMachine<StateId,Event>	create() Create the state machine.
SubStateMachineBuilder<StateId,Event>	get() Return the builder for the top level state machine.

Methods inherited from class java.lang.Object

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

Constructor Detail

StateMachineBuilder

public StateMachineBuilder()

Method Detail

get

public SubStateMachineBuilder<StateId,Event> get()

Return the builder for the top level state machine.

create

public IStateMachine<StateId,Event> create()

Create the state machine. After calling this method, the created state machine is detached from this method. Calling get() after this results in a builder for a completely new state machine.

Returns:

The created state machine.