/*
* Copyright 2015-2016 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.statemachine.ensemble;
import org.springframework.statemachine.StateMachine;
import org.springframework.statemachine.StateMachineContext;
/**
* {@code StateMachineEnsemble} is a contract between a {@link StateMachine} and
* arbitrary ensemble of other {@link StateMachine}s.
*
* @author Janne Valkealahti
*
* @param <S> the type of state
* @param <E> the type of event
*/
public interface StateMachineEnsemble<S, E> {
/**
* Request a join to a state machine ensemble. This method
* is a request to join an ensemble and doesn't guarantee
* a requester will eventually successfully join. Join operation
* needs to be used together with {@link EnsembleListener} and
* {@link EnsembleListener#stateMachineJoined(StateMachine, StateMachineContext)}
* is called with a {@link StateMachine} instance for successful join.
*
* @param stateMachine the state machine
*/
void join(StateMachine<S, E> stateMachine);
/**
* Request a leave from an ensemble. This method is a request to
* leave an ensemble. After this method is called no further processing
* is done for a instance of {@link StateMachine}. Additionally
* {@link EnsembleListener#stateMachineLeft(StateMachine, StateMachineContext)}
* is called when leave request is fully processed.
*
* @param stateMachine the state machine
*/
void leave(StateMachine<S, E> stateMachine);
/**
* Adds the ensemble listener.
*
* @param listener the listener
*/
void addEnsembleListener(EnsembleListener<S, E> listener);
/**
* Removes the ensemble listener.
*
* @param listener the listener
*/
void removeEnsembleListener(EnsembleListener<S, E> listener);
/**
* Sets the state as a {@link StateMachineContext}.
*
* @param context the state machine context
*/
void setState(StateMachineContext<S, E> context);
/**
* Gets the state as a {@link StateMachineContext}.
*
* @return the state machine context
*/
StateMachineContext<S, E> getState();
/**
* Gets the ensemble leader. If returned machine
* is {@code NULL} it indicates that this ensemble
* doesn't know any leader.
*
* @return the ensemble leader
*/
StateMachine<S, E> getLeader();
}