CleanerFileReader


1   /*-
2    * See the file LICENSE for redistribution information.
3    *
4    * Copyright (c) 2002,2006 Oracle.  All rights reserved.
5    *
6    * $Id: CleanerFileReader.java,v 1.33 2006/10/30 21:14:20 bostic Exp $
7    */
8   
9   package com.sleepycat.je.log;
10  
11  import java.io.IOException  ;
12  import java.nio.ByteBuffer  ;
13  import java.util.HashMap  ;
14  import java.util.Map  ;
15  
16  import com.sleepycat.je.DatabaseException;
17  import com.sleepycat.je.dbi.DatabaseId;
18  import com.sleepycat.je.dbi.EnvironmentImpl;
19  import com.sleepycat.je.log.entry.INLogEntry;
20  import com.sleepycat.je.log.entry.LNLogEntry;
21  import com.sleepycat.je.log.entry.LogEntry;
22  import com.sleepycat.je.tree.IN;
23  import com.sleepycat.je.tree.LN;
24  import com.sleepycat.je.utilint.DbLsn;
25  
26  /**
27   * CleanerFileReader scans log files for INs and LNs.
28   */
29  public class CleanerFileReader extends FileReader {
30      private static final byte IS_IN = 0;
31      private static final byte IS_LN = 1;
32      private static final byte IS_ROOT = 2;
33      private static final byte IS_FILEHEADER = 3;
34  
35      private Map   targetEntryMap;
36      private LogEntry targetLogEntry;
37      private byte targetCategory;
38  
39      /**
40       * Create this reader to start at a given LSN.
41       * @param env The relevant EnvironmentImpl.
42       * @param readBufferSize buffer size in bytes for reading in log.
43       * @param startLsn where to start in the log, or null for the beginning.
44       * @param fileNum single file number.
45       */
46      public CleanerFileReader(EnvironmentImpl env,
47                               int readBufferSize, 
48                               long startLsn,
49                               Long   fileNum)
50          throws IOException  , DatabaseException {
51  
52          super(env,
53                readBufferSize,
54                true,                     // forward
55                startLsn,
56                fileNum,                  // single file number
57                DbLsn.NULL_LSN,           // endOfFileLsn
58                DbLsn.NULL_LSN);          // finishLsn
59  
60          targetEntryMap = new HashMap  ();
61  
62          addTargetType(IS_LN, LogEntryType.LOG_LN_TRANSACTIONAL);
63          addTargetType(IS_LN, LogEntryType.LOG_LN);
64          addTargetType(IS_LN, LogEntryType.LOG_NAMELN_TRANSACTIONAL);
65          addTargetType(IS_LN, LogEntryType.LOG_NAMELN);
66          addTargetType(IS_LN, LogEntryType.LOG_MAPLN_TRANSACTIONAL);
67          addTargetType(IS_LN, LogEntryType.LOG_MAPLN);
68          addTargetType(IS_LN, LogEntryType.LOG_DEL_DUPLN_TRANSACTIONAL);
69          addTargetType(IS_LN, LogEntryType.LOG_DEL_DUPLN);
70          addTargetType(IS_LN, LogEntryType.LOG_DUPCOUNTLN_TRANSACTIONAL);
71          addTargetType(IS_LN, LogEntryType.LOG_DUPCOUNTLN);
72          addTargetType(IS_LN, LogEntryType.LOG_FILESUMMARYLN);
73          addTargetType(IS_IN, LogEntryType.LOG_IN);
74          addTargetType(IS_IN, LogEntryType.LOG_BIN);
75          addTargetType(IS_IN, LogEntryType.LOG_DIN);
76          addTargetType(IS_IN, LogEntryType.LOG_DBIN);
77          addTargetType(IS_ROOT, LogEntryType.LOG_ROOT);
78          addTargetType(IS_FILEHEADER, LogEntryType.LOG_FILE_HEADER);
79      }
80  
81      private void addTargetType(byte category, LogEntryType entryType)
82          throws DatabaseException {
83  
84          targetEntryMap.put(entryType,
85                             new EntryInfo(entryType.getNewLogEntry(),
86                       category));
87      }
88  
89      /**
90       * Helper for determining the starting position and opening
91       * up a file at the desired location.
92       */
93      protected void initStartingPosition(long endOfFileLsn,
94                                          Long   fileNum)
95          throws IOException  , DatabaseException {
96  
97          eof = false;
98  
99          /*
100          * Start off at the startLsn. If that's null, start at the
101          * beginning of the log. If there are no log files, set
102          * eof.
103          */
104         readBufferFileNum = fileNum.longValue();
105         readBufferFileEnd = 0;
106 
107         /* 
108          * After we read the first entry, the currentEntry will
109          * point here.
110          */
111         nextEntryOffset = readBufferFileEnd;
112     }
113 
114     /** 
115      * @return true if this is a type we're interested in.
116      */
117     protected boolean isTargetEntry(byte entryTypeNum,
118                                     byte entryTypeVersion) {
119 
120         LogEntryType fromLogType = new LogEntryType(entryTypeNum,
121                             entryTypeVersion);
122                                                             
123         /* Is it a target entry? */
124         EntryInfo info = (EntryInfo) targetEntryMap.get(fromLogType);
125         if (info == null) {
126             return false;
127         } else {
128             targetCategory = info.targetCategory;
129             targetLogEntry = info.targetLogEntry;
130             return true;
131         }
132     }
133 
134     /**
135      * This reader instantiates an LN and key for every LN entry.
136      */
137     protected boolean processEntry(ByteBuffer   entryBuffer)
138         throws DatabaseException {
139 
140         targetLogEntry.readEntry(entryBuffer, currentEntrySize,
141                                  currentEntryTypeVersion, true);
142         return true;
143     }
144 
145     /**
146      * @return true if the last entry was an IN.
147      */
148     public boolean isIN() {
149         return (targetCategory == IS_IN);
150     }
151 
152     /**
153      * @return true if the last entry was a LN.
154      */
155     public boolean isLN() {
156         return (targetCategory == IS_LN);
157     }
158 
159     /**
160      * @return true if the last entry was a root
161      */
162     public boolean isRoot() {
163         return (targetCategory == IS_ROOT);
164     }
165 
166     public boolean isFileHeader() {
167         return (targetCategory == IS_FILEHEADER);
168     }
169 
170     /**
171      * Get the last LN seen by the reader.
172      */
173     public LN getLN() {
174         return ((LNLogEntry) targetLogEntry).getLN();
175     }
176 
177     /**
178      * Get the last entry seen by the reader as an IN.
179      */
180     public IN getIN() 
181         throws DatabaseException {
182 
183         return ((INLogEntry) targetLogEntry).getIN(env);
184     }
185 
186     public FileHeader getFileHeader() 
187         throws DatabaseException {
188 
189         return (FileHeader) (targetLogEntry.getMainItem());
190     }
191 
192     /**
193      * Get the last databaseId seen by the reader.
194      */
195     public DatabaseId getDatabaseId() {
196         if (targetCategory == IS_LN) {
197             return ((LNLogEntry) targetLogEntry).getDbId(); 
198         } else if (targetCategory == IS_IN) {
199             return ((INLogEntry) targetLogEntry).getDbId(); 
200         } else {
201         return null;
202         }
203     }
204 
205     /**
206      * Get the last key seen by the reader.
207      */
208     public byte[] getKey() {
209         return ((LNLogEntry) targetLogEntry).getKey();
210     }
211 
212     /**
213      * Get the last key seen by the reader.
214      */
215     public byte[] getDupTreeKey() {
216         return ((LNLogEntry) targetLogEntry).getDupKey();
217     }
218 
219     private static class EntryInfo {
220         public LogEntry targetLogEntry;
221         public byte     targetCategory;
222 
223         EntryInfo(LogEntry targetLogEntry, byte targetCategory) {
224             this.targetLogEntry = targetLogEntry;
225             this.targetCategory = targetCategory;
226         }
227     }
228 }
229
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags