com.github.rinde.rinsim.fsm.State Maven / Gradle / Ivy
/*
* Copyright (C) 2011-2018 Rinde R.S. van Lon
*
* 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 com.github.rinde.rinsim.fsm;
import javax.annotation.Nullable;
/**
* Defines a state in a state machine.
* @author Rinde van Lon
* @param Trigger type, see {@link StateMachine} for details.
* @param Context type, see {@link StateMachine} for details.
*/
public interface State {
/**
* @return The name of the state.
*/
String name();
/**
* Should handle the trigger. Allows the state to take control and react to
* the trigger.
* @param trigger The trigger that should be handled.
* @param context The context of the state.
* @return A trigger or null. If null is returned
* there will be no state transition. If the returned trigger (except
* null) is not supported by this state (as defined by
* the {@link StateMachine}) a {@link IllegalArgumentException} will
* be thrown by the {@link StateMachine} .
*/
@Nullable
T handle(@Nullable T trigger, C context);
/**
* This method is called at the moment the {@link StateMachine} 'enters' this
* state (i.e. during a state transition). It is called just before the
* {@link #handle(Object, Object)} is called.
* @param trigger The trigger that triggered the transition.
* @param context The context of the state.
*/
void onEntry(T trigger, C context);
/**
* This method is called at the moment the {@link StateMachine} 'exits' this
* state (i.e. during a state transition).
* @param trigger The trigger that triggered the transition.
* @param context The context of the state.
*/
void onExit(T trigger, C context);
}