/*
* Copyright 2015 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 EnsembleListener} for various ensemble events.
*
* @author Janne Valkealahti
*
* @param <S> the type of state
* @param <E> the type of event
*/
public interface EnsembleListener<S, E> {
/**
* Called when state machine joined an ensemble. This callback
* is guaranteed to be called for a {@link StateMachine} who
* requested a join. User of this listener should check that a
* {@link StateMachine} is the one interested of. Implementation
* may choose to notify other {@link StateMachine} joins if it is
* able to do so. This may be called multiple time in case ensemble
* has made a choice to leave machine due to ensemble errors.
*
* @param stateMachine the state machine
* @param context the state machine context
*/
void stateMachineJoined(StateMachine<S, E> stateMachine, StateMachineContext<S, E> context);
/**
* Called when state machine left an ensemble. This callback
* is guaranteed to be called for a {@link StateMachine} who
* requested a leave. User of this listener should check that a
* {@link StateMachine} is the one interested of. Implementation
* may choose to notify other {@link StateMachine} leaves if it is
* able to do so.
*
* @param stateMachine the state machine
* @param context the state machine context
*/
void stateMachineLeft(StateMachine<S, E> stateMachine, StateMachineContext<S, E> context);
/**
* Called when ensemble is discovering a state change.
*
* @param context the state machine context
*/
void stateChanged(StateMachineContext<S, E> context);
/**
* Called when {@link StateMachineEnsemble} resulted an error.
*
* @param exception the exception
*/
void ensembleError(StateMachineEnsembleException exception);
/**
* Called when a state machine is granted a leader role
* in an ensemble.
*
* @param stateMachine the state machine
*/
void ensembleLeaderGranted(StateMachine<S, E> stateMachine);
/**
* Called when a state machine is revoked from a leader role
* in an ensemble.
*
* @param stateMachine the state machine
*/
void ensembleLeaderRevoked(StateMachine<S, E> stateMachine);
}