LogWriter


1   /*******************************************************************************
2    * Copyright (c) 2000, 2005 IBM Corporation and others.
3    * All rights reserved. This program and the accompanying materials
4    * are made available under the terms of the Eclipse Public License v1.0
5    * which accompanies this distribution, and is available at
6    * http://www.eclipse.org/legal/epl-v10.html
7    * 
8    * Contributors:
9    *     IBM Corporation - initial API and implementation
10   *******************************************************************************/
11  package org.eclipse.core.internal.indexing;
12  
13  import java.io.FileOutputStream  ;
14  import java.io.IOException  ;
15  import java.util.Iterator  ;
16  import java.util.Map  ;
17  
18  class LogWriter {
19  
20      protected FileOutputStream   out;
21      protected PageStore pageStore;
22  
23      /**
24       * Puts the modified pages to the log file.
25       */
26      public static void putModifiedPages(PageStore pageStore, Map   modifiedPages) throws PageStoreException {
27          LogWriter writer = new LogWriter();
28          try {
29              writer.open(pageStore);
30              writer.putModifiedPages(modifiedPages);
31          } finally {
32              writer.close();
33          }
34      }
35  
36      /**
37       * Opens the log.
38       */
39      protected void open(PageStore store) throws PageStoreException {
40          this.pageStore = store;
41          try {
42              out = new FileOutputStream  (Log.name(store.getName()));
43          } catch (IOException   e) {
44              throw new PageStoreException(PageStoreException.LogOpenFailure, e);
45          }
46      }
47  
48      /**
49       * Closes the log.
50       */
51      protected void close() {
52          try {
53              if (out != null)
54                  out.close();
55          } catch (IOException   e) {
56              // ignore
57          }
58          out = null;
59      }
60  
61      /**
62       * Puts the modified pages into the log.
63       */
64      protected void putModifiedPages(Map   modifiedPages) throws PageStoreException {
65          Buffer b4 = new Buffer(4);
66          byte[] pageBuffer = new byte[Page.SIZE];
67          int numberOfPages = modifiedPages.size();
68          b4.put(0, 4, numberOfPages);
69          try {
70              write(b4.getByteArray());
71              Iterator   pageStream = modifiedPages.values().iterator();
72              while (pageStream.hasNext()) {
73                  Page page = (Page) pageStream.next();
74                  int pageNumber = page.getPageNumber();
75                  b4.put(0, 4, pageNumber);
76                  write(b4.getByteArray());
77                  page.toBuffer(pageBuffer);
78                  write(pageBuffer);
79              }
80          } catch (IOException   e) {
81              throw new PageStoreException(PageStoreException.LogWriteFailure, e);
82          }
83      }
84  
85      public void write(byte[] buffer) throws IOException   {
86          out.write(buffer);
87      }
88  
89  }
90
A to Z: JavaDoc & Examples Daily Java News & Articles Open Source Projects Open Source Codes Free Computer Books Remove Frame
Popular Tags