| package org.apache.helix.examples; |
| |
| /* |
| * Licensed to the Apache Software Foundation (ASF) under one |
| * or more contributor license agreements. See the NOTICE file |
| * distributed with this work for additional information |
| * regarding copyright ownership. The ASF licenses this file |
| * to you 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. |
| */ |
| |
| import java.util.UUID; |
| |
| import org.apache.helix.ClusterMessagingService; |
| import org.apache.helix.Criteria; |
| import org.apache.helix.HelixManager; |
| import org.apache.helix.InstanceType; |
| import org.apache.helix.NotificationContext; |
| import org.apache.helix.model.Message; |
| import org.apache.helix.model.Message.MessageState; |
| import org.apache.helix.model.Message.MessageType; |
| import org.apache.helix.participant.statemachine.StateModel; |
| import org.apache.helix.participant.statemachine.StateModelFactory; |
| import org.apache.helix.participant.statemachine.StateModelInfo; |
| import org.apache.helix.participant.statemachine.Transition; |
| |
| public class BootstrapHandler extends StateModelFactory<StateModel> { |
| |
| @Override |
| public StateModel createNewStateModel(String resourceName, String stateUnitKey) { |
| return new BootstrapStateModel(stateUnitKey); |
| } |
| |
| @StateModelInfo(initialState = "OFFLINE", states = "{'OFFLINE','SLAVE','MASTER'}") |
| public static class BootstrapStateModel extends StateModel { |
| |
| private final String _stateUnitKey; |
| |
| public BootstrapStateModel(String stateUnitKey) { |
| _stateUnitKey = stateUnitKey; |
| |
| } |
| |
| @Transition(from = "MASTER", to = "SLAVE") |
| public void masterToSlave(Message message, NotificationContext context) { |
| |
| } |
| |
| @Transition(from = "OFFLINE", to = "SLAVE") |
| public void offlineToSlave(Message message, NotificationContext context) { |
| System.out.println("BootstrapProcess.BootstrapStateModel.offlineToSlave()"); |
| HelixManager manager = context.getManager(); |
| ClusterMessagingService messagingService = manager.getMessagingService(); |
| Message requestBackupUriRequest = |
| new Message(MessageType.USER_DEFINE_MSG, UUID.randomUUID().toString()); |
| requestBackupUriRequest.setMsgSubType(BootstrapProcess.REQUEST_BOOTSTRAP_URL); |
| requestBackupUriRequest.setMsgState(MessageState.NEW); |
| Criteria recipientCriteria = new Criteria(); |
| recipientCriteria.setInstanceName("*"); |
| recipientCriteria.setRecipientInstanceType(InstanceType.PARTICIPANT); |
| recipientCriteria.setResource(message.getResourceName()); |
| recipientCriteria.setPartition(message.getPartitionName()); |
| recipientCriteria.setSessionSpecific(true); |
| // wait for 30 seconds |
| int timeout = 30000; |
| BootstrapReplyHandler responseHandler = new BootstrapReplyHandler(); |
| |
| int sentMessageCount = |
| messagingService.sendAndWait(recipientCriteria, requestBackupUriRequest, responseHandler, |
| timeout); |
| if (sentMessageCount == 0) { |
| // could not find any other node hosting the partition |
| } else if (responseHandler.getBootstrapUrl() != null) { |
| System.out.println("Got bootstrap url:" + responseHandler.getBootstrapUrl()); |
| System.out.println("Got backup time:" + responseHandler.getBootstrapTime()); |
| // Got the url fetch it |
| } else { |
| // Either go to error state |
| // throw new Exception("Cant find backup/bootstrap data"); |
| // Request some node to start backup process |
| } |
| } |
| |
| @Transition(from = "SLAVE", to = "OFFLINE") |
| public void slaveToOffline(Message message, NotificationContext context) { |
| System.out.println("BootstrapProcess.BootstrapStateModel.slaveToOffline()"); |
| } |
| |
| @Transition(from = "SLAVE", to = "MASTER") |
| public void slaveToMaster(Message message, NotificationContext context) { |
| System.out.println("BootstrapProcess.BootstrapStateModel.slaveToMaster()"); |
| } |
| |
| } |
| } |