| package org.apache.helix.manager.zk; |
| |
| /* |
| * 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 org.I0Itec.zkclient.DataUpdater; |
| import org.apache.helix.ZNRecord; |
| import org.apache.helix.model.CurrentState; |
| |
| /** |
| * updater for carrying over last current states |
| * |
| * @see HELIX-30: ZkHelixManager.carryOverPreviousCurrentState() should use a special merge logic |
| * |
| * because carryOver() is performed after addLiveInstance(). it's possible that carryOver() |
| * overwrites current-state updates performed by current session. so carryOver() should be |
| * performed only when current-state is empty for the partition |
| * |
| */ |
| class CurStateCarryOverUpdater implements DataUpdater<ZNRecord> { |
| final String _curSessionId; |
| final String _initState; |
| final CurrentState _lastCurState; |
| |
| public CurStateCarryOverUpdater(String curSessionId, String initState, CurrentState lastCurState) { |
| if (curSessionId == null || initState == null || lastCurState == null) { |
| throw new IllegalArgumentException("missing curSessionId|initState|lastCurState for carry-over"); |
| } |
| _curSessionId = curSessionId; |
| _initState = initState; |
| _lastCurState = lastCurState; |
| } |
| |
| @Override |
| public ZNRecord update(ZNRecord currentData) { |
| CurrentState curState = null; |
| if (currentData == null) { |
| curState = new CurrentState(_lastCurState.getId()); |
| // copy all simple fields settings and overwrite session-id to current session |
| curState.getRecord().setSimpleFields(_lastCurState.getRecord().getSimpleFields()); |
| curState.setSessionId(_curSessionId); |
| } else |
| { |
| curState = new CurrentState(currentData); |
| } |
| |
| for (String partitionName : _lastCurState.getPartitionStateMap().keySet()) { |
| // carry-over only when current-state not exist |
| if (curState.getState(partitionName) == null) { |
| curState.setState(partitionName, _initState); |
| } |
| } |
| return curState.getRecord(); |
| } |
| |
| } |