import java.io.*;

import java.util.ArrayList;

import java.util.List;

import java.util.concurrent.TimeoutException;

public class LogCompactor {

public static void compactLog(String logFilePath, long timeoutMillis) throws IOException, TimeoutException {

// Read all lines from the log file

List<String> lines = readAllLines(logFilePath);

if (lines == null || lines.isEmpty()) {

System.out.println("Log file is empty.");

return;

}

// Compact the log - output only the last 'n' lines (e.g., last 100)

int numLinesToKeep = Math.min(100, lines.size()); //Keep last 100 lines or all lines if less than 100

List<String> compactedLines = lines.subList(lines.size() - numLinesToKeep, lines.size());

// Write the compacted lines to a new file

writeLinesToFile(compactedLines, "compacted_" + logFilePath);

System.out.println("Log file compacted to: compacted_" + logFilePath);

}

private static List<String> readAllLines(String filePath) throws IOException {

List<String> lines = new ArrayList<>();

try (BufferedReader reader = new BufferedReader(new FileReader(filePath))) {

String line;

while ((line = reader.readLine()) != null) {

lines.add(line);

}

}

return lines;

}

private static void writeLinesToFile(List<String> lines, String filePath) throws IOException {

try (BufferedWriter writer = new BufferedWriter(new FileWriter(filePath))) {

for (String line : lines) {

writer.write(line);

writer.newLine();

}

}

}

public static void main(String[] args) throws IOException, TimeoutException {

//Example usage

String logFile = "test.log"; // Replace with your log file path

long timeout = 5000; // Timeout in milliseconds

//Create a dummy log file for testing

try (BufferedWriter writer = new BufferedWriter(new FileWriter(logFile))) {

for (int i = 0; i < 200; i++) {

writer.write("Log line " + (i + 1) + "\n");

}

}

try {

compactLog(logFile, timeout);

} catch (IOException | TimeoutException e) {

System.err.println("Error compacting log file: " + e.getMessage());

e.printStackTrace();

}

}

}