/*
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* The contents of this file are subject to the terms of the Common Development and
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* Distribution License (the License). You may not use this file except in compliance with the
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* License.
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*
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* You can obtain a copy of the License at legal/CDDLv1.0.txt. See the License for the
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* specific language governing permission and limitations under the License.
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*
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* When distributing Covered Software, include this CDDL Header Notice in each file and include
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* the License file at legal/CDDLv1.0.txt. If applicable, add the following below the CDDL
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* Header, with the fields enclosed by brackets [] replaced by your own identifying
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* information: "Portions Copyright [year] [name of copyright owner]".
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*
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* Copyright 2008 Sun Microsystems, Inc.
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*/
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package org.opends.server.replication.common;
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/**
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* This class contains static methods to implement the DS status state machine.
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* They are used to validate the transitions of the state machine according to
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* the current status and event, and to compute the new status.
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* - Status (states of the state machine) are defined in ServerStatus enum
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* - Events are defined in StateMachineEvent enum
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*/
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public class StatusMachine
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{
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/**
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* Checks if a given status is valid as an entering status for the state
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* machine.
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* @param initStatus Initial status to check.
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* @return True if the passed status is a valid initial status.
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*/
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public static boolean isValidInitialStatus(ServerStatus initStatus)
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{
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switch (initStatus)
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{
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case NORMAL_STATUS:
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case DEGRADED_STATUS:
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case BAD_GEN_ID_STATUS:
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return true;
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}
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return false;
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}
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/**
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* Computes the new status of the state machine according to the current
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* status and the new generated event.
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* @param curStatus The current status we start from.
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* @param event The event that must make the current status evolve.
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* @return The newly computed status. If the state transition is impossible
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* according to state machine, special INVALID_STATUS is returned.
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*/
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public static ServerStatus computeNewStatus(ServerStatus curStatus,
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StatusMachineEvent event)
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{
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switch (curStatus)
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{
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// From NOT_CONNECTED_STATUS
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case NOT_CONNECTED_STATUS:
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switch (event)
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{
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case TO_NOT_CONNECTED_STATUS_EVENT:
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return ServerStatus.NOT_CONNECTED_STATUS;
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case TO_NORMAL_STATUS_EVENT:
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return ServerStatus.NORMAL_STATUS;
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case TO_DEGRADED_STATUS_EVENT:
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return ServerStatus.DEGRADED_STATUS;
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case TO_BAD_GEN_ID_STATUS_EVENT:
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return ServerStatus.BAD_GEN_ID_STATUS;
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default:
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return ServerStatus.INVALID_STATUS;
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}
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// From NORMAL_STATUS
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case NORMAL_STATUS:
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switch (event)
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{
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case TO_NOT_CONNECTED_STATUS_EVENT:
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return ServerStatus.NOT_CONNECTED_STATUS;
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case TO_NORMAL_STATUS_EVENT:
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return ServerStatus.NORMAL_STATUS;
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case TO_DEGRADED_STATUS_EVENT:
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return ServerStatus.DEGRADED_STATUS;
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case TO_FULL_UPDATE_STATUS_EVENT:
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return ServerStatus.FULL_UPDATE_STATUS;
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case TO_BAD_GEN_ID_STATUS_EVENT:
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return ServerStatus.BAD_GEN_ID_STATUS;
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default:
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return ServerStatus.INVALID_STATUS;
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}
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// From DEGRADED_STATUS
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case DEGRADED_STATUS:
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switch (event)
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{
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case TO_NOT_CONNECTED_STATUS_EVENT:
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return ServerStatus.NOT_CONNECTED_STATUS;
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case TO_NORMAL_STATUS_EVENT:
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return ServerStatus.NORMAL_STATUS;
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case TO_DEGRADED_STATUS_EVENT:
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return ServerStatus.DEGRADED_STATUS;
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case TO_FULL_UPDATE_STATUS_EVENT:
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return ServerStatus.FULL_UPDATE_STATUS;
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case TO_BAD_GEN_ID_STATUS_EVENT:
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return ServerStatus.BAD_GEN_ID_STATUS;
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default:
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return ServerStatus.INVALID_STATUS;
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}
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// From FULL_UPDATE_STATUS
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case FULL_UPDATE_STATUS:
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switch (event)
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{
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case TO_NOT_CONNECTED_STATUS_EVENT:
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return ServerStatus.NOT_CONNECTED_STATUS;
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case TO_FULL_UPDATE_STATUS_EVENT:
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return ServerStatus.FULL_UPDATE_STATUS;
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default:
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return ServerStatus.INVALID_STATUS;
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}
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// From BAD_GEN_ID_STATUS
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case BAD_GEN_ID_STATUS:
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switch (event)
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{
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case TO_NOT_CONNECTED_STATUS_EVENT:
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return ServerStatus.NOT_CONNECTED_STATUS;
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case TO_FULL_UPDATE_STATUS_EVENT:
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return ServerStatus.FULL_UPDATE_STATUS;
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case TO_BAD_GEN_ID_STATUS_EVENT:
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return ServerStatus.BAD_GEN_ID_STATUS;
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default:
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return ServerStatus.INVALID_STATUS;
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}
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default:
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return ServerStatus.INVALID_STATUS;
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}
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}
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}
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