Merge remote-tracking branch 'origin/league-model'

# Conflicts:
#	src/main/java/design/controller/userinput/menus/MainMenu.java
#	src/main/java/design/model/Golfer.java
#	src/test/java/design/model/ClubTest.java
#	src/test/java/design/model/GolferTest.java

16 files changed, 640 insertions, 45 deletions

diff --git a/src/main/java/design/controller/userinput/menus/LeageMenu.java b/src/main/java/design/controller/userinput/menus/LeageMenu.java
new file mode 100644
index 0000000..d9afa91
--- /dev/null
+++ b/src/main/java/design/controller/userinput/menus/LeageMenu.java
@@ -0,0 +1,30 @@
+package design.controller.userinput.menus;
+
+import design.controller.userinput.Menu;
+import design.controller.userinput.MenuOption;
+import design.model.League;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class LeageMenu extends Menu {
+    private final League league;
+
+    public LeageMenu(League league) {
+        this.league = league;
+    }
+
+    @Override
+    public String getTitle() {
+        return "League Menu";
+    }
+
+    @Override
+    public List<MenuOption> getMenuOptions() {
+        List<MenuOption> options = new ArrayList<>();
+        options.add(new MenuOption("statistics...", () -> {}));
+        options.add(new MenuOption("leaderboard...", () -> {}));
+        options.add(new MenuOption("log round...", () -> {}));
+        return options;
+    }
+}
diff --git a/src/main/java/design/controller/userinput/menus/MainMenu.java b/src/main/java/design/controller/userinput/menus/MainMenu.java
index 8a30258..75ad88f 100644
--- a/src/main/java/design/controller/userinput/menus/MainMenu.java
+++ b/src/main/java/design/controller/userinput/menus/MainMenu.java
@@ -38,8 +38,8 @@ public class MainMenu extends Menu {
                     new MenuOption("manage courses...", () -> new ManageCourses().present()),
                     new MenuOption("manage clubs...", () -> new ManageClubs().present()),
                     new MenuOption("statistics...", () -> new StatisticsMenu().present()),
-                    new MenuOption("log round...", () -> new HolePlayMenu().present())
-
+                    new MenuOption("log round...", () -> new HolePlayMenu().present()),
+                    new MenuOption("League play...", () -> new SelectLeague().present())
             );
         }
     }
diff --git a/src/main/java/design/controller/userinput/menus/ManageClubs.java b/src/main/java/design/controller/userinput/menus/ManageClubs.java
index d186cac..9c23433 100644
--- a/src/main/java/design/controller/userinput/menus/ManageClubs.java
+++ b/src/main/java/design/controller/userinput/menus/ManageClubs.java
@@ -65,7 +65,8 @@ public class ManageClubs extends Menu {
             selector.present();
             Club.ClubType type = selector.getResult();
 
-            golfer.addClub(manufacture, nickname, type);
+            Club c = new Club(manufacture, nickname, type);
+            golfer.addClub(c);
 
             // Add club to JSON
             try {
diff --git a/src/main/java/design/controller/userinput/menus/SelectLeague.java b/src/main/java/design/controller/userinput/menus/SelectLeague.java
new file mode 100644
index 0000000..08f6c91
--- /dev/null
+++ b/src/main/java/design/controller/userinput/menus/SelectLeague.java
@@ -0,0 +1,83 @@
+package design.controller.userinput.menus;
+
+import design.controller.userinput.Menu;
+import design.controller.userinput.MenuOption;
+import design.model.Golfer;
+import design.model.League;
+import design.model.ScrambleLeague;
+import design.model.StrokeLeague;
+import design.persistence.LeagueDatabase;
+import design.runtime.Session;
+
+import java.io.IOException;
+import java.text.ParseException;
+import java.text.SimpleDateFormat;
+import java.util.*;
+
+public class SelectLeague extends Menu {
+    private final Golfer golfer = Session.getCurrentGolfer();
+
+    @Override
+    public String getTitle() {
+        return "Select League";
+    }
+
+    @Override
+    public List<MenuOption> getMenuOptions() {
+        List<MenuOption> options = new ArrayList<>();
+        for (League l : LeagueDatabase.instance().getLeagues()) {
+            options.add(new MenuOption(l.getName(), () -> {
+                if (l instanceof ScrambleLeague sl && sl.locateTeam(golfer) == null) {
+                    Scanner sc = new Scanner(System.in);
+                    System.out.print("You are not a member of a team for this league. Would you like to create one (Y/n): ");
+                    if (sc.next().equals("n")) {
+                        new MainMenu().present();
+                    } else {
+                        // create team
+                    }
+                } else {
+                    new LeageMenu(l).present();
+                }
+            }));
+        }
+        options.add(new MenuOption("<create>", this::createLeagueWizard));
+        return options;
+    }
+
+    private void createLeagueWizard() {
+        try {
+            Scanner scanner = new Scanner(System.in);
+            SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd");
+
+            System.out.print("Enter league name: ");
+            String name = scanner.nextLine();
+
+            System.out.print("Enter registration date (yyyy-MM-dd): ");
+            Date registrationDate = dateFormat.parse(scanner.nextLine());
+
+            System.out.print("Enter start date (yyyy-MM-dd): ");
+            Date startDate = dateFormat.parse(scanner.nextLine());
+
+            System.out.print("Enter end date (yyyy-MM-dd): ");
+            Date endDate = dateFormat.parse(scanner.nextLine());
+
+            Golfer owner = Session.getCurrentGolfer();
+
+            System.out.print("Enter format (stroke/scramble): ");
+            String scramble = scanner.nextLine();
+
+            League league;
+            switch (scramble) {
+                case "scramble" -> league = new ScrambleLeague(name, registrationDate, startDate, endDate, owner);
+                case "stroke" -> league = new StrokeLeague(name, registrationDate, startDate, endDate, owner);
+                default -> throw new RuntimeException();
+            }
+            LeagueDatabase.instance().addLeague(league);
+        } catch (ParseException ex) {
+            System.out.println("Invalid format");
+        } catch (IOException ex) {
+            System.out.println("Error writing to file");
+        }
+        this.present();
+    }
+}
diff --git a/src/main/java/design/model/Club.java b/src/main/java/design/model/Club.java
index b12fd99..c19811c 100644
--- a/src/main/java/design/model/Club.java
+++ b/src/main/java/design/model/Club.java
@@ -1,5 +1,6 @@
 package design.model;
 
+import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonIdentityInfo;
 import com.fasterxml.jackson.annotation.ObjectIdGenerators;
 
@@ -21,18 +22,26 @@ public class Club {
         PUTTER
     }
 
-    private final int id;
+    private int id;
     private final String manufacture;
     private final String nickname;
     private final ClubType clubType;
 
-    public Club(int id, String manufacture, String nickname, ClubType clubType) {
+    @JsonCreator
+    private Club(int id, String manufacture, String nickname, ClubType clubType) {
         this.id = id;
         this.manufacture = manufacture;
         this.nickname = nickname;
         this.clubType = clubType;
     }
 
+    public Club(String manufacture, String nickname, ClubType clubType) {
+        this.id = -1;
+        this.manufacture = manufacture;
+        this.nickname = nickname;
+        this.clubType = clubType;
+    }
+
     public int getId() {
         return id;
     }
@@ -49,6 +58,11 @@ public class Club {
         return clubType;
     }
 
+    public void setId(int id) {
+        assert this.id == -1;
+        this.id = id;
+    }
+
     @Override
     public String toString() {
         return String.format("#%d %s - %s (%s)", id, nickname, manufacture, clubType);
diff --git a/src/main/java/design/model/Invite.java b/src/main/java/design/model/Invite.java
new file mode 100644
index 0000000..479f520
--- /dev/null
+++ b/src/main/java/design/model/Invite.java
@@ -0,0 +1,25 @@
+package design.model;
+
+import java.util.Date;
+
+public class Invite {
+    private final Team team;
+    private final Date sendDate;
+
+    public Invite(Team team, Date sendDate) {
+        this.team = team;
+        this.sendDate = sendDate;
+    }
+
+    public Team getTeam() {
+        return team;
+    }
+
+    public Date getSendDate() {
+        return sendDate;
+    }
+
+    public void accept(Golfer g) {
+        team.addMember(g);
+    }
+}
diff --git a/src/main/java/design/model/League.java b/src/main/java/design/model/League.java
new file mode 100644
index 0000000..881e25f
--- /dev/null
+++ b/src/main/java/design/model/League.java
@@ -0,0 +1,90 @@
+package design.model;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonSubTypes;
+import com.fasterxml.jackson.annotation.JsonTypeInfo;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+@JsonTypeInfo(
+        use = JsonTypeInfo.Id.NAME,
+        include = JsonTypeInfo.As.PROPERTY,
+        property = "type"
+)
+@JsonSubTypes({
+        @JsonSubTypes.Type(value = ScrambleLeague.class, name = "scramble"),
+        @JsonSubTypes.Type(value = StrokeLeague.class, name = "stroke")
+})
+public abstract class League {
+    private int id;
+    private final String name;
+    private final Date registrationDate;
+    private final Date startDate;
+    private final Date endDate;
+    private final Golfer owner;
+    private final List<Match> schedule;
+
+    @JsonCreator
+    protected League(int id, String name, Date registrationDate, Date startDate, Date endDate, Golfer owner, List<Match> schedule) {
+        this.id = id;
+        this.name = name;
+        this.registrationDate = registrationDate;
+        this.startDate = startDate;
+        this.endDate = endDate;
+        this.owner = owner;
+        this.schedule = schedule != null ? schedule : new ArrayList<>();
+    }
+
+    public League(String name, Date registrationDate, Date startDate, Date endDate, Golfer owner) {
+        this.id = -1;
+        this.name = name;
+        this.registrationDate = registrationDate;
+        this.startDate = startDate;
+        this.endDate = endDate;
+        this.owner = owner;
+        this.schedule = new ArrayList<>();
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Date getRegistrationDate() {
+        return registrationDate;
+    }
+
+    public Date getStartDate() {
+        return startDate;
+    }
+
+    public Date getEndDate() {
+        return endDate;
+    }
+
+    public Golfer getOwner() {
+        return owner;
+    }
+
+    public Match[] getSchedule() {
+        return schedule.toArray(Match[]::new);
+    }
+
+    public void addMatchToSchedule(Match match) {
+        Date date = match.getDateScheduled();
+        if(date.after(endDate)){
+            throw new IllegalArgumentException("Cannot create match after league has ended");
+        }
+        schedule.add(match);
+    }
+
+    public void setId(int id) {
+        assert this.id == -1;
+        this.id = id;
+    }
+}
diff --git a/src/main/java/design/model/Match.java b/src/main/java/design/model/Match.java
new file mode 100644
index 0000000..4f01c98
--- /dev/null
+++ b/src/main/java/design/model/Match.java
@@ -0,0 +1,57 @@
+package design.model;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+public class Match {
+    private final Course course;
+    private final Date dateScheduled;
+    private final LocalDateTime start;
+    private final int holeCount;
+    private final List<Round> rounds;
+
+    @JsonCreator
+    private Match(Course course, Date dateScheduled, LocalDateTime start, int holeCount, List<Round> rounds) {
+        this.course = course;
+        this.dateScheduled = dateScheduled;
+        this.start = start;
+        this.holeCount = holeCount;
+        this.rounds = rounds;
+    }
+
+    public Match(Course course, Date dateScheduled, LocalDateTime start, int holeCount) {
+        this.course = course;
+        this.dateScheduled = dateScheduled;
+        this.start = start;
+        this.holeCount = holeCount;
+        this.rounds = new ArrayList<>();
+    }
+
+    public Course getCourse() {
+        return course;
+    }
+
+    public Date getDateScheduled() {
+        return dateScheduled;
+    }
+
+    public LocalDateTime getStart() {
+        return start;
+    }
+
+    public int getHoleCount() {
+        return holeCount;
+    }
+
+    public boolean addRound(Round round) {
+        return rounds.add(round);
+    }
+
+    public Round[] getRounds() {
+        return rounds.toArray(Round[]::new);
+    }
+}
diff --git a/src/main/java/design/model/ScrambleLeague.java b/src/main/java/design/model/ScrambleLeague.java
new file mode 100644
index 0000000..d372264
--- /dev/null
+++ b/src/main/java/design/model/ScrambleLeague.java
@@ -0,0 +1,46 @@
+package design.model;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Date;
+import java.util.List;
+
+@JsonTypeName("scramble")
+public class ScrambleLeague extends League {
+    private final List<Team> participants;
+
+    @JsonCreator
+    private ScrambleLeague(int id, String name, Date registrationDate, Date startDate, Date endDate, Golfer owner, List<Team> participants, List<Match> schedule) {
+        super(id, name, registrationDate, startDate, endDate, owner, schedule);
+        this.participants = participants;
+    }
+
+    public ScrambleLeague(String name, Date registrationDate, Date startDate, Date endDate, Golfer owner) {
+        super(name, registrationDate, startDate, endDate, owner);
+        this.participants = new ArrayList<>();
+    }
+
+    public boolean addParticipants(Team e) {
+        return participants.add(e);
+    }
+
+    public boolean removeParticipants(Team o) {
+        return participants.remove(o);
+    }
+
+    public Team[] getParticipants() {
+        return participants.toArray(Team[]::new);
+    }
+
+    public Team locateTeam(Golfer golfer) {
+        for (Team participant : participants) {
+            if (List.of(participant.getMembers()).contains(golfer)) {
+                return participant;
+            }
+        }
+        return null;
+    }
+}
diff --git a/src/main/java/design/model/StrokeLeague.java b/src/main/java/design/model/StrokeLeague.java
new file mode 100644
index 0000000..2b787b5
--- /dev/null
+++ b/src/main/java/design/model/StrokeLeague.java
@@ -0,0 +1,36 @@
+package design.model;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonTypeName;
+
+import java.util.ArrayList;
+import java.util.Date;
+import java.util.List;
+
+@JsonTypeName("stroke")
+public class StrokeLeague extends League {
+    private final List<Golfer> participants;
+
+    @JsonCreator
+    private StrokeLeague(int id, String name, Date registrationDate, Date startDate, Date endDate, Golfer owner, List<Golfer> participants, List<Match> schedule) {
+        super(id, name, registrationDate, startDate, endDate, owner, schedule);
+        this.participants = participants;
+    }
+
+    public StrokeLeague(String name, Date registrationDate, Date startDate, Date endDate, Golfer owner) {
+        super(name, registrationDate, startDate, endDate, owner);
+        this.participants = new ArrayList<>();
+    }
+
+    public boolean addParticipants(Golfer e) {
+        return participants.add(e);
+    }
+
+    public boolean removeParticipants(Golfer o) {
+        return participants.remove(o);
+    }
+
+    public Golfer[] getParticipants() {
+        return participants.toArray(Golfer[]::new);
+    }
+}
diff --git a/src/main/java/design/model/Team.java b/src/main/java/design/model/Team.java
new file mode 100644
index 0000000..53b276e
--- /dev/null
+++ b/src/main/java/design/model/Team.java
@@ -0,0 +1,40 @@
+package design.model;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Team {
+    private String name;
+    private final List<Golfer> members;
+    private final Golfer owner;
+
+    public Team(String name, Golfer owner) {
+        this.name = name;
+        this.owner = owner;
+        this.members = new ArrayList<>();
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public Golfer[] getMembers() {
+        return members.toArray(Golfer[]::new);
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public boolean addMember(Golfer golfer) {
+        return members.add(golfer);
+    }
+
+    public boolean removeMember(Golfer g) {
+        return members.remove(g);
+    }
+
+    public Golfer getOwner() {
+        return owner;
+    }
+}
diff --git a/src/main/java/design/persistence/JSONLeagueDatabase.java b/src/main/java/design/persistence/JSONLeagueDatabase.java
new file mode 100644
index 0000000..8a55065
--- /dev/null
+++ b/src/main/java/design/persistence/JSONLeagueDatabase.java
@@ -0,0 +1,102 @@
+package design.persistence;
+
+import com.fasterxml.jackson.annotation.JsonAutoDetect;
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.PropertyAccessor;
+import com.fasterxml.jackson.core.StreamReadFeature;
+import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.json.JsonMapper;
+import com.fasterxml.jackson.databind.module.SimpleModule;
+import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
+import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
+import design.model.Course;
+import design.model.Golfer;
+import design.model.League;
+
+import java.io.File;
+import java.io.IOException;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.Map;
+
+public class JSONLeagueDatabase implements LeagueDatabase {
+
+    private static JSONLeagueDatabase INSTANCE;
+
+    public static JSONLeagueDatabase instance() {
+        if (INSTANCE == null) {
+            INSTANCE = new JSONLeagueDatabase("data/leaguedb.json");
+        }
+        return INSTANCE;
+    }
+
+    private final Map<Integer, League> cache;
+    private final ObjectMapper mapper;
+    private final File file;
+    private int nextLeagueID;
+
+    public JSONLeagueDatabase(String filename) {
+        this.file = new File(filename);
+        this.cache = new HashMap<>();
+        this.mapper = JsonMapper.builder().enable(StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION).build();
+
+        SimpleModule module = new SimpleModule();
+        module.addDeserializer(Course.class, new Serializers.CourseIdDeserializer());
+        module.addSerializer(Course.class, new Serializers.CourseIdSerializer());
+        module.addDeserializer(Golfer.class, new Serializers.GolferUsernameDeserializer());
+        module.addSerializer(Golfer.class, new Serializers.GolferUsernameSerializer());
+        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
+        mapper.registerModule(module);
+        mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
+        mapper.registerModule(new ParameterNamesModule(JsonCreator.Mode.PROPERTIES));
+        mapper.registerModule(new JavaTimeModule());
+
+        try {
+            load();
+        } catch (IOException ex) {
+            throw new RuntimeException(ex);
+        }
+
+        this.nextLeagueID = cache.values().stream().mapToInt(League::getId).max().orElse(0) + 1;
+    }
+
+    private void load() throws IOException {
+        League[] data = mapper.readValue(file, League[].class);
+        cache.clear();
+        Arrays.stream(data).forEach(i -> cache.put(i.getId(), i));
+    }
+
+    private void save() throws IOException {
+        League[] data = cache.values().toArray(League[]::new);
+        mapper.writer(new Serializers.CustomPrettyPrinter()).writeValue(file, data);
+    }
+
+    @Override
+    public League getLeague(int id) {
+        return cache.get(id);
+    }
+
+    @Override
+    public League[] getLeagues() {
+        return cache.values().toArray(League[]::new);
+    }
+
+    @Override
+    public void addLeague(League league) throws IOException {
+        league.setId(nextLeagueID++);
+        cache.putIfAbsent(league.getId(), league);
+        save();
+    }
+
+    @Override
+    public void removeLeague(League league) throws IOException {
+        cache.remove(league.getId());
+        save();
+    }
+
+    @Override
+    public void updateLeague(League league) throws IOException {
+        cache.put(league.getId(), league);
+        save();
+    }
+}
diff --git a/src/main/java/design/persistence/JSONPersonalDatabase.java b/src/main/java/design/persistence/JSONPersonalDatabase.java
index 70aa1ab..30c280a 100644
--- a/src/main/java/design/persistence/JSONPersonalDatabase.java
+++ b/src/main/java/design/persistence/JSONPersonalDatabase.java
@@ -3,21 +3,18 @@ package design.persistence;
 import com.fasterxml.jackson.annotation.JsonAutoDetect;
 import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.PropertyAccessor;
-import com.fasterxml.jackson.core.JsonGenerator;
-import com.fasterxml.jackson.core.JsonParser;
-import com.fasterxml.jackson.core.util.DefaultIndenter;
-import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
+import com.fasterxml.jackson.core.StreamReadFeature;
 import com.fasterxml.jackson.databind.*;
+import com.fasterxml.jackson.databind.json.JsonMapper;
 import com.fasterxml.jackson.databind.module.SimpleModule;
 import com.fasterxml.jackson.datatype.jsr310.JavaTimeModule;
 import com.fasterxml.jackson.module.paramnames.ParameterNamesModule;
-import design.model.Club;
 import design.model.Course;
 import design.model.Golfer;
+import design.model.League;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.Collection;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -39,15 +36,17 @@ public class JSONPersonalDatabase implements PersonalDatabase {
     private JSONPersonalDatabase(String filename) {
         this.file = new File(filename);
         this.cache = new HashMap<>();
-        this.mapper = new ObjectMapper();
+        this.mapper = JsonMapper.builder().enable(StreamReadFeature.INCLUDE_SOURCE_IN_LOCATION).build();;
 
         // TODO: Once the saved JSON matches the model, consider removing.
         // TEMP: tolerate unknown props while the model stabilizes
         mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
 
         SimpleModule module = new SimpleModule();
-        module.addDeserializer(Course.class, new CourseIdDeserializer());
-        module.addSerializer(Course.class, new CourseIdSerializer());
+        module.addDeserializer(Course.class, new Serializers.CourseIdDeserializer());
+        module.addSerializer(Course.class, new Serializers.CourseIdSerializer());
+        module.addSerializer(League.class, new Serializers.LeagueIDSerializer());
+        module.addDeserializer(League.class, new Serializers.LeagueIDDeserializer());
         mapper.registerModule(module);
         mapper.setVisibility(PropertyAccessor.FIELD, JsonAutoDetect.Visibility.ANY);
         mapper.registerModule(new ParameterNamesModule(JsonCreator.Mode.PROPERTIES));
@@ -70,7 +69,7 @@ public class JSONPersonalDatabase implements PersonalDatabase {
 
     private void save() throws IOException {
         Golfer[] data = cache.values().toArray(Golfer[]::new);
-        mapper.writer(new CustomPrettyPrinter()).writeValue(file, data);
+        mapper.writer(new Serializers.CustomPrettyPrinter()).writeValue(file, data);
     }
 
     // turns that collection into a real array of golfers
@@ -101,34 +100,4 @@ public class JSONPersonalDatabase implements PersonalDatabase {
         cache.put(golfer.getUsername(), golfer);
         save();
     }
-
-    private static class CourseIdSerializer extends JsonSerializer<Course> {
-        @Override
-        public void serialize(Course course, JsonGenerator gen, SerializerProvider serializers) throws IOException {
-            gen.writeNumber(course.getId());
-        }
-    }
-
-    private static class CourseIdDeserializer extends JsonDeserializer<Course> {
-        MasterDatabase masterDB = MasterDatabase.instance();
-
-        @Override
-        public Course deserialize(JsonParser p, DeserializationContext context) throws IOException {
-            int id = p.getValueAsInt();
-            return masterDB.getCourse(id);
-        }
-    }
-
-    private static class CustomPrettyPrinter extends DefaultPrettyPrinter {
-        public CustomPrettyPrinter() {
-            super._arrayIndenter = new DefaultIndenter();
-            super._objectFieldValueSeparatorWithSpaces = _separators.getObjectFieldValueSeparator() + " ";
-            super._arrayEmptySeparator = "";
-        }
-
-        @Override
-        public CustomPrettyPrinter createInstance() {
-            return new CustomPrettyPrinter();
-        }
-    }
 }
diff --git a/src/main/java/design/persistence/LeagueDatabase.java b/src/main/java/design/persistence/LeagueDatabase.java
new file mode 100644
index 0000000..953624d
--- /dev/null
+++ b/src/main/java/design/persistence/LeagueDatabase.java
@@ -0,0 +1,21 @@
+package design.persistence;
+
+import design.model.League;
+
+import java.io.IOException;
+
+public interface LeagueDatabase {
+    static LeagueDatabase instance() {
+        return JSONLeagueDatabase.instance();
+    }
+
+    League getLeague(int id);
+
+    League[] getLeagues();
+
+    void addLeague(League league) throws IOException;
+
+    void removeLeague(League league) throws IOException;
+
+    void updateLeague(League league) throws IOException;
+}
diff --git a/src/main/java/design/persistence/MasterDatabase.java b/src/main/java/design/persistence/MasterDatabase.java
index 59e3ebd..86e326b 100644
--- a/src/main/java/design/persistence/MasterDatabase.java
+++ b/src/main/java/design/persistence/MasterDatabase.java
@@ -10,6 +10,8 @@ public interface MasterDatabase {
     }
 
     Course[] getCourses();
+
     CourseList getCourseList(); // unique from courses as this is a composite of ICourses.
+
     Course getCourse(int id);
 }
diff --git a/src/main/java/design/persistence/Serializers.java b/src/main/java/design/persistence/Serializers.java
new file mode 100644
index 0000000..3940b44
--- /dev/null
+++ b/src/main/java/design/persistence/Serializers.java
@@ -0,0 +1,79 @@
+package design.persistence;
+
+import com.fasterxml.jackson.core.JsonGenerator;
+import com.fasterxml.jackson.core.JsonParser;
+import com.fasterxml.jackson.core.util.DefaultIndenter;
+import com.fasterxml.jackson.core.util.DefaultPrettyPrinter;
+import com.fasterxml.jackson.databind.DeserializationContext;
+import com.fasterxml.jackson.databind.JsonDeserializer;
+import com.fasterxml.jackson.databind.JsonSerializer;
+import com.fasterxml.jackson.databind.SerializerProvider;
+import design.model.Course;
+import design.model.Golfer;
+import design.model.League;
+
+import java.io.IOException;
+
+public class Serializers {
+    public static class CustomPrettyPrinter extends DefaultPrettyPrinter {
+        public CustomPrettyPrinter() {
+            super._arrayIndenter = new DefaultIndenter();
+            super._objectFieldValueSeparatorWithSpaces = _separators.getObjectFieldValueSeparator() + " ";
+            super._arrayEmptySeparator = "";
+        }
+
+        @Override
+        public CustomPrettyPrinter createInstance() {
+            return new CustomPrettyPrinter();
+        }
+    }
+
+    public static class CourseIdSerializer extends JsonSerializer<Course> {
+        @Override
+        public void serialize(Course course, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+            gen.writeNumber(course.getId());
+        }
+    }
+
+    public static class CourseIdDeserializer extends JsonDeserializer<Course> {
+        @Override
+        public Course deserialize(JsonParser p, DeserializationContext context) throws IOException {
+            MasterDatabase masterDB = MasterDatabase.instance();
+            int id = p.getValueAsInt();
+            return masterDB.getCourse(id);
+        }
+    }
+
+    public static class LeagueIDSerializer extends JsonSerializer<League> {
+        @Override
+        public void serialize(League value, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+            gen.writeNumber(value.getId());
+        }
+    }
+
+    public static class LeagueIDDeserializer extends JsonDeserializer<League> {
+        @Override
+        public League deserialize(JsonParser p, DeserializationContext ctxt) throws IOException {
+            LeagueDatabase leagueDB = LeagueDatabase.instance();
+            int id = p.getValueAsInt();
+            return leagueDB.getLeague(id);
+        }
+    }
+
+    public static class GolferUsernameSerializer extends JsonSerializer<Golfer> {
+        @Override
+        public void serialize(Golfer course, JsonGenerator gen, SerializerProvider serializers) throws IOException {
+            gen.writeString(course.getUsername());
+        }
+    }
+
+    public static class GolferUsernameDeserializer extends JsonDeserializer<Golfer> {
+
+        @Override
+        public Golfer deserialize(JsonParser p, DeserializationContext context) throws IOException {
+            PersonalDatabase personalDB = PersonalDatabase.instance();
+            String username = p.getValueAsString();
+            return personalDB.getGolfer(username);
+        }
+    }
+}