Added Logging class.

.gitignore

@@ -1,3 +1,4 @@
 .idea/*
 target/*
 *.iml
+log/*

src/main/java/nl/andrewlalis/Main.java

@@ -1,11 +1,13 @@
 package nl.andrewlalis;
 
 import nl.andrewlalis.model.Team;
+import nl.andrewlalis.util.Logging;
 import nl.andrewlalis.util.TeamGenerator;
 
 import java.io.IOException;
 import java.util.List;
 import java.util.Map;
+import java.util.logging.Logger;
 
 import nl.andrewlalis.util.CommandLine;
 
@@ -14,18 +16,27 @@ import nl.andrewlalis.util.CommandLine;
  */
 public class Main {
 
+    private static final Logger logger = Logger.getGlobal();
+
     public static void main(String[] args) throws IOException {
 
-        System.out.println("Initializer for Github Repositories in Educational Organizations.");
-
+        // Parsed command line arguments.
         Map<String, String> userOptions = CommandLine.parseArgs(args);
 
+        // Initialize logger.
+        try {
+            Logging.setup(true); // TODO: Replace true with command line arg.
+        } catch (IOException e) {
+            logger.severe("Unable to save log to file.");
+        }
+
+        logger.info("Initializer for Github Repositories in Educational Organizations.");
+
         List<Team> teams = TeamGenerator.generateFromCSV(
                 userOptions.get("input"),
                 Integer.parseInt(userOptions.get("teamsize"))
         );
-        System.out.println(teams);
-
+        logger.info("Teams created: " + teams);
 
     }
 }

src/main/java/nl/andrewlalis/util/Logging.java

@@ -0,0 +1,31 @@
+package nl.andrewlalis.util;
+
+import java.io.IOException;
+import java.util.logging.*;
+
+/**
+ * Responsible for creating logs to standard output and writing to files.
+ */
+public class Logging {
+
+    private static FileHandler outputFile;
+    private static SimpleFormatter formatter;
+
+    public static void setup(boolean verbose) throws IOException {
+        Logger logger = Logger.getGlobal();
+
+        if (verbose) {
+            logger.setLevel(Level.FINEST);
+        } else {
+            logger.setLevel(Level.INFO);
+        }
+
+        outputFile = new FileHandler("log/latest.txt");
+        formatter = new SimpleFormatter();
+
+        outputFile.setFormatter(formatter);
+        logger.addHandler(outputFile);
+
+    }
+
+}

src/main/java/nl/andrewlalis/util/TeamGenerator.java

@@ -8,14 +8,43 @@ import org.apache.commons.csv.CSVRecord;
 import java.io.FileReader;
 import java.io.IOException;
 import java.util.*;
+import java.util.logging.Logger;
 
 public class TeamGenerator {
 
-    public static List<Team> generateFromCSV(String filename, int teamSize) throws IOException {
-        System.out.println("Generating teams of size " + teamSize);
+    private static final Logger logger = Logger.getLogger(TeamGenerator.class.getName());
+    static {
+        logger.setParent(Logger.getGlobal());
+    }
+
+    /**
+     * Creates a list of teams by reading a CSV file of a certain format. The format for each column is as follows:
+     * 1. Timestamp - The date and time the record was entered.
+     * 2. Username - The email address.
+     * 3. Name - The student's name.
+     * 4. Student Number
+     * 5. Github Username
+     * 6. I have chosen a partner. (Yes / No) If yes:
+     *      7. Your Partner's Student Number
+     * @param filename The CSV file to load from.
+     * @param teamSize The preferred teamsize used in creating teams.
+     * @return A list of teams.
+     * @throws IOException If the file is unable to be read.
+     * @throws IllegalArgumentException If an invalid teamsize is given.
+     */
+    public static List<Team> generateFromCSV(String filename, int teamSize) throws IOException, IllegalArgumentException {
+        logger.info("Generating teams of size " + teamSize);
+        if (teamSize < 1) {
+            logger.severe("Invalid team size.");
+            throw new IllegalArgumentException("Team size must be greater than or equal to 1. Got " + teamSize);
+        }
+        logger.finest("Parsing CSV file.");
         Iterable<CSVRecord> records = CSVFormat.DEFAULT.withFirstRecordAsHeader().parse(new FileReader(filename));
 
+        logger.finest("Reading all records into map.");
         Map<Integer, Student> studentMap = readAllStudents(records, teamSize);
+
+        logger.finest("Generating all valid teams from student map.");
         return generateAllValidTeams(studentMap, teamSize);
     }