2martens
/
dis
1
0
Fork 0
Code Issues 1 Pull Requests Projects Releases Wiki Activity

Added recovery method 

Signed-off-by: Jim Martens <github@2martens.de>
This commit is contained in:
Jim Martens 2017-05-24 15:32:00 +02:00
parent 364ecae424
commit cd7be5eac8
1 changed files with 48 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
04/src/PersistenceManager.java
View File

@ -1,7 +1,6 @@
import org.jetbrains.annotations.Contract;
import java.io.FileWriter;
import java.io.IOException;
import java.io.*;
import java.util.*;
/**
@ -103,6 +102,53 @@ public class PersistenceManager {
persist();
}
/**
* Performs the recovery actions.
*/
public void recovery() {
try {
BufferedReader reader = new BufferedReader(new FileReader("../data/log.txt"));
String line;
List<Integer> winner_tas = new ArrayList<>();
while ((line = reader.readLine()) != null) {
String[] cols = line.split(",");
if (cols[2].equals("COMMIT")) {
winner_tas.add(Integer.valueOf(cols[1]));
}
}
reader.close();
reader = new BufferedReader(new FileReader("../data/log.txt"));
while ((line = reader.readLine()) != null) {
String[] cols = line.split(",");
if (!cols[2].equals("WRITE") || !winner_tas.contains(Integer.valueOf(cols[1]))) {
continue;
}
int lsn = Integer.valueOf(cols[0]);
int pageID = Integer.valueOf(cols[3]);
String data = cols[4];
BufferedReader readPage = new BufferedReader(new FileReader("../data/" + pageID + ".txt"));
String pageLine = readPage.readLine();
readPage.close();
String[] pageCols = pageLine.split(",");
int pageLSN = Integer.parseInt(pageCols[1]);
if (pageLSN >= lsn) {
continue;
}
FileWriter writer = new FileWriter("../data/" + pageID + ".txt");
writer.write("" + pageID + "," + lsn + "," + data + "\n");
writer.close();
}
reader.close();
} catch (IOException e) {
e.printStackTrace();
}
}
/**
* Logs a write to the log file.
*