Feat: add log file on disk

src/main/java/com/sheepit/client/Log.java

@@ -19,6 +19,11 @@
 
 package com.sheepit.client;
 
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Paths;
+import java.nio.file.StandardOpenOption;
 import java.text.DateFormat;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
@@ -36,8 +41,11 @@ public class Log {
 	
 	private boolean printStdOut;
 	
-	private Log(boolean print_) {
+	private String logFile;
+	
+	private Log(boolean print_, String logDirectory_) {
 		this.printStdOut = print_;
+		this.logFile = logDirectory_ + File.separator + "sheepit.log";
 		this.lastCheckPoint = 0;
 		this.checkpoints.put(this.lastCheckPoint, new ArrayList<String>());
 		this.dateFormat = new SimpleDateFormat("dd-MM HH:mm:ss");
@@ -81,6 +89,15 @@ public class Log {
 				if (this.printStdOut) {
 					System.out.println(line);
 				}
+				
+				if (this.logFile != null && this.logFile.isEmpty() == false) {
+					try {
+						Files.write(Paths.get(this.logFile), (line + "\n").getBytes(), StandardOpenOption.APPEND, StandardOpenOption.CREATE);
+					}
+					catch (IOException e) {
+						// :( catch-22,  we can't really write the exception on the log file
+					}
+				}
 			}
 		}
 		catch (Exception e) {
@@ -109,11 +126,14 @@ public class Log {
 	
 	public static synchronized Log getInstance(Configuration config) {
 		if (instance == null) {
+			String path = null;
 			boolean print = false;
 			if (config != null) {
 				print = config.isPrintLog();
+				path = config.getLogDirectory() == null ? null : config.getLogDirectory();
 			}
-			instance = new Log(print);
+			
+			instance = new Log(print, path);
 		}
 		return instance;
 	}