1/*- 2 * See the file LICENSE for redistribution information. 3 * 4 * Copyright (c) 2002,2008 Oracle. All rights reserved. 5 * 6 * $Id: RecoveryOperation.java,v 12.7 2008/01/17 05:04:53 mjc Exp $ 7 */ 8 9package com.sleepycat.db; 10 11import com.sleepycat.db.internal.DbConstants; 12 13/** 14The recovery operation being performed when {@link com.sleepycat.db.LogRecordHandler#handleLogRecord LogRecordHandler.handleLogRecord} is called. 15*/ 16public final class RecoveryOperation { 17 /** 18 The log is being read backward to determine which transactions have 19 been committed and to abort those operations that were not; undo the 20 operation described by the log record. 21 */ 22 public static final RecoveryOperation BACKWARD_ROLL = 23 new RecoveryOperation("BACKWARD_ROLL", DbConstants.DB_TXN_BACKWARD_ROLL); 24 /** 25 The log is being played forward; redo the operation described by the log 26 record. 27 <p> 28 The FORWARD_ROLL and APPLY operations frequently imply the same actions, 29 redoing changes that appear in the log record, although if a recovery 30 function is to be used on a replication client where reads may be taking 31 place concurrently with the processing of incoming messages, APPLY 32 operations should also perform appropriate locking. 33 */ 34 public static final RecoveryOperation FORWARD_ROLL = 35 new RecoveryOperation("FORWARD_ROLL", DbConstants.DB_TXN_FORWARD_ROLL); 36 /** 37 The log is being read backward during a transaction abort; undo the 38 operation described by the log record. 39 */ 40 public static final RecoveryOperation ABORT = 41 new RecoveryOperation("ABORT", DbConstants.DB_TXN_ABORT); 42 /** 43 The log is being applied on a replica site; redo the operation 44 described by the log record. 45 <p> 46 The FORWARD_ROLL and APPLY operations frequently imply the same actions, 47 redoing changes that appear in the log record, although if a recovery 48 function is to be used on a replication client where reads may be taking 49 place concurrently with the processing of incoming messages, APPLY 50 operations should also perform appropriate locking. 51 */ 52 public static final RecoveryOperation APPLY = 53 new RecoveryOperation("APPLY", DbConstants.DB_TXN_APPLY); 54 /** 55 The log is being printed for debugging purposes; print the contents of 56 this log record in the desired format. 57 */ 58 public static final RecoveryOperation PRINT = 59 new RecoveryOperation("PRINT", DbConstants.DB_TXN_PRINT); 60 61 private String operationName; 62 private int flag; 63 64 private RecoveryOperation(String operationName, int flag) { 65 this.operationName = operationName; 66 this.flag = flag; 67 } 68 69 /** {@inheritDoc} */ 70 public String toString() { 71 return "RecoveryOperation." + operationName; 72 } 73 74 /* This is public only so it can be called from internal/DbEnv.java. */ 75 /** 76 Internal: this is public only so it can be called from an internal 77 package. 78 * 79 @param flag 80 the internal flag value to be wrapped in a RecoveryException object 81 */ 82 public static RecoveryOperation fromFlag(int flag) { 83 switch (flag) { 84 case DbConstants.DB_TXN_BACKWARD_ROLL: 85 return BACKWARD_ROLL; 86 case DbConstants.DB_TXN_FORWARD_ROLL: 87 return FORWARD_ROLL; 88 case DbConstants.DB_TXN_ABORT: 89 return ABORT; 90 case DbConstants.DB_TXN_APPLY: 91 return APPLY; 92 case DbConstants.DB_TXN_PRINT: 93 return PRINT; 94 default: 95 throw new IllegalArgumentException( 96 "Unknown recover operation: " + flag); 97 } 98 } 99} 100