org.neo4j.cluster.statemachine.State Maven / Gradle / Ivy
Show all versions of ongdb-cluster Show documentation
/*
* Copyright (c) 2018-2020 "Graph Foundation"
* Graph Foundation, Inc. [https://graphfoundation.org]
*
* Copyright (c) 2002-2018 "Neo4j,"
* Neo4j Sweden AB [http://neo4j.com]
*
* This file is part of ONgDB Enterprise Edition. The included source
* code can be redistributed and/or modified under the terms of the
* GNU AFFERO GENERAL PUBLIC LICENSE Version 3
* (http://www.fsf.org/licensing/licenses/agpl-3.0.html) as found
* in the associated LICENSE.txt file.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*/
package org.neo4j.cluster.statemachine;
import org.neo4j.cluster.com.message.Message;
import org.neo4j.cluster.com.message.MessageHolder;
import org.neo4j.cluster.com.message.MessageType;
/**
* Implemented by states in a state machine. Each state must
* implement the handle method, to perform different things depending
* on the message that comes in. This should only be implemented as enums.
*
* A state is guaranteed to only have one handle at a time, i.e. access is serialized.
*/
public interface State
{
/**
* Handle a message. The state can use context for state storage/retrieval and it will also act
* as a facade to the rest of the system. The MessageProcessor is used to trigger new messages.
* When the handling is done the state returns the next state of the state machine.
*
*
* @param context that contains state and methods to access other parts of the system
* @param message that needs to be handled
* @param outgoing processor for new messages created by the handling of this message
* @return the new state
*/
State handle( CONTEXT context, Message message, MessageHolder outgoing ) throws Throwable;
}