.devcontainer/Dockerfile

+FROM openjdk:17-jdk-slim-bullseye
+
+# Install some basic development utilities
+RUN apt-get update && apt-get install -y \ 
+  curl \
+  git \
+  python3 \
+  zip \
+  && rm -rf /var/lib/apt/lists/* \
+  && curl -fsSL https://deb.nodesource.com/setup_17.x | bash \
+  && apt-get install -y nodejs \
+  && npm install -g yarn \
+  && rm -rf /var/lib/apt/lists/* 
+
+# User the Java-based launcher as Alpine Linux and Graal native compiled images of CS don't like
+# Alpine Linux (due to musl instead of gcc)
+RUN bash -c 'curl -fLo /usr/bin/cs https://git.io/coursier-cli' && \
+    chmod u+x /usr/bin/cs
+
+# Put Coursier-installed artifacts on the path
+ENV PATH="$PATH:/root/.local/share/coursier/bin"   
+
+# Get sbt
+RUN bash -c 'cs install sbt'
+
+# Get http server
+RUN bash -c 'npm install -g http-server'
+
+# Precache sbt version as part of the image.
+ARG SBT_VERSION=1.7.0
+ARG SCALA_VERSION=3.1.3
+ARG SCALAJS_VERSION=1.10.1
+RUN mkdir -p /sbtprecacheproj/project && \
+  cd /sbtprecacheproj && \
+  echo sbt.version=${SBT_VERSION} > project/build.properties && \
+  echo 'addSbtPlugin("org.scala-js" % "sbt-scalajs" % "'${SCALAJS_VERSION}'")' > project/plugins.sbt && \
+  echo '@main def hello = println("hello")' > main.scala && \
+  echo 'enablePlugins(ScalaJSPlugin); scalaVersion := "'${SCALA_VERSION}'"' > build.sbt && \
+  sbt fastLinkJS && cd / && rm -r -f /tmp/sbt-precompile

.devcontainer/devcontainer.json

+{
+    "name": "Doctacular codespace config",
+    "build": {
+        "dockerfile": "Dockerfile"
+    },
+    "extensions": [
+      "vscjava.vscode-java-pack"
+    ]  
+  }
\ No newline at end of file

.gitignore

+# This file tells git what files to "ignore"
+# Typically, these are all the generated files (as we only commit source code, not binary output)
+
+.gradle/
+.idea/
+build/
+
+.vscode
+bin/
+.openvscode-server/

README.md

+## A Git, GitLab, and JUnit exercise
+
+This assignment is intended to give you a relatively small exercise to give you a little familiarisation working with Git, Gradle,
+JUnit, and some more recent Java language features on a very small codebase - 
+before you and your group do something much more exciting on the much larger class-wide project.
+
+The example code you have been given is a simple Java "dots and boxes" game. It has a couple of known bugs in it
+(already commented for you - the task is not really in finding the bugs). Please note: your task **is not simply to fix the bugs**. 
+Your task is a series of steps that show you can work with git, gitlab, gradle, and junit.
+
+You will notice that this is a git repository, but it is provided to you just as a zip that you download.
+If you run `git status`, you should see that you are on branch `main`.
+
+Dots And Boxes is normally a two-player pencil-and-paper game. See https://en.wikipedia.org/wiki/Dots_and_Boxes  
+In our version, a player "draws" a line by clicking on it. If it completes a square, they automatically claim the
+square and get another turn. There are two known bugs in our code-base:
+
+1. The code for checking if a square is complete is wrong. It just returns `true` at the moment, whereas it should
+   test if the lines surrounding the square have been "drawn".
+2. The grid doesn't complain if you "draw" a line that has already been drawn. It should throw an `IllegalStateException`.
+
+Remember, your task *isn't* just to fix the bugs.
+
+Your tasks:
+
+1. Create a repository on gitlab.une.edu.au and push the main branch of this repository to it **entirely unmodified**. 
+   **You will need to set the visibility on your repository so that the marker can read from it**. 
+   Repositories we cannot access cannot be marked (and will receive 0 until you can fix it)
+   
+2. Set your name and email on the repository for your future commits, using `git config`
+
+3. Update the "name" label in the application to show **your name**.
+   Commit this change and push it to your **main** branch.
+
+3. Create an Issue in your GitLab project for fixing the errors in the assignment.
+   
+4. Create and check out a branch for your bugfix. 
+   This should follow the convention of having the issue number, followed by a hyphenated description of the issue.
+   e.g. `1-fix-assignment-errors`.  
+   Push this branch to your remote repository. (From here on, I'll refer to this as your "issue branch")
+
+5. Create **unit tests** that will detect the errors in the code. Particularly:
+   * That the algorithm for testing whether a box is complete is wrong.
+   * That the DotsAndBoxesGrid currently permits you to "draw" a line that has already been drawn, whereas it should throw an exception.
+    
+6. Commit these unit tests with an appropriately descriptive commit message.  
+   **Do not fix the bugs in this commit. The unit tests should *fail*.**    
+   Push this commit to your remote repository (on your issue branch)
+
+7. **Tag** this commit, with the label `testsfail`. Push this tag to your remote repository.
+
+8. Fix the bugs in the code. Run your unit tests again. The tests should now pass.
+
+9. Commit your bugfix. Push it to your issue branch.
+
+10. Check out `main`. Merge your issue branch to main. The tests should still pass. Push this to your gitlab repository.
+
+11. Close your issue with a reference to the commit hash in which you fixed the bugs.
+
+12. Paste the link to your gitlab repository into the assignment and submit.
+
+Marking. 
+
+1. You have submitted a link to your repository on gitlab.une.edu.au and it is visible to the marker (1 point)
+2. The first few commits on the main branch on the repository contains the starter code, showing me as author. 
+   The last of my commits has the *same commit hash* as in the original code I gave you.  
+   (i.e. you successfully pushed the original code I gave you to your GitLab repository). (1 point)
+3. The next commit on the main branch adds your name to the label and shows you as author  
+   (i.e. you have successfully configured your name & email and you have successfully created and pushed a commit) (1 point)
+4. You have at least one issue on your repository for the bugfixes. It is closed referencing the bugfix commit. (1 point)
+5. There is a `testsfail` tag in your repository (1 point)
+6. Checking out the `testsfail` tag, and running the `gradlew test`, produces two failed tests (one for each bug). (2 points)
+7. Checking out the main branch, both tests are present and pass (2 points)
+8. The most recent commit on the `main` branch is a merge commit, merging the commit in which you set your name on the label
+   and the commit in which you fixed the tests. (1 point)
+
+
+## Features of this code base
+
+As well as being an assignment repository, this codebase is also a sample codebase, showing you a few things:
+
+* It uses a *gradle wrapper* (a script that will download the correct version of gradle for you.) This means you can
+  `./gradlew build` and it'll go get gradle before it builds. Normally, that would fetch from a URL on the gradle site,
+  but so this works behind UNE's webproxy, the gradle jar is also checked into the repository.
+  
+* It contains Log4J, which is the logging library (basically, super-powered printlns) that we will use.
+
+* It uses some more recent Java features. e.g. record classes and lambdas.
+  These may be familiar to students who've studied Scala, but they are making their way into Java too. 
+  For instance, notice that in `DotsAndBoxesUI` we register listeners onto the dots and boxes grid by registering lambda functions.
+  
+  ```java
+   grid.addConsumer((g) -> {
+      updateLabel();
+      canvas.repaint();
+   });
+  ```
+  
+  In Java, functions aren't "first class citizens" in the way they are in Scala, however. Our code here is really 
+  creating an *anonymous inner class*.
+  
+  Instead, Java has the idea of "SAM types" (Single Abstract Method types). `addConsumer` asks for an *object* of type
+  `Consumer<DotsAndBoxesGrid>`. But `Consumer<>` has only one abstract method. So, Java gives us the shorthand
+  that if we just describe how we want to implement the abstract method (`(g) -> { ...`) then the Java compiler will 
+  fill in the rest of the code about creating an anonymous inner class of type `Consumer<>` for us.
+
+  Record classes are similar to Scala's "case classes", e.g. 
+
+  ```java
+  record Vertical(int col, int row) {
+      Rectangle rect() {
+            int x = corner(col);
+            int y = corner(row) + dotDiameter + gap;
+            return new Rectangle(x, y, dotDiameter, lineLength);
+      }
+
+      /** Whether or not this line contains this point */
+      boolean contains(int x, int y) {
+            return rect().contains(x, y);
+      }
+
+      /** Paints this element, based on the passed in grid */
+      public void draw(DotsAndBoxesGrid grid, Graphics2D g2d) {
+            g2d.setColor(grid.getVertical(col, row) ? Color.DARK_GRAY : Color.LIGHT_GRAY);
+            g2d.fill(this.rect());
+      }
+  }
+  ```
+
+  Particularly, `col` and `row` are made to be fields of a `Vertical` instance and the constructor is
+  automatically defined. (So is `toString` and `hashCode`, but we're not using those.)
+
+  Record classes aren't as common in Java code-bases, but they're available in Java 17, so students might use 
+  them in the group project, so let's give you a little example of them!
\ No newline at end of file

build.gradle

+buildscript {
+    repositories {
+        maven { url 'https://hopper.une.edu.au/artifactory/libs-release/' }
+        mavenCentral()
+    }
+}
+
+plugins {
+    id 'application'
+}
+
+group 'org.example'
+version '1.0-SNAPSHOT'
+
+
+repositories {
+    maven { url 'https://hopper.une.edu.au/artifactory/libs-release/' }
+    mavenCentral()
+}
+
+dependencies {
+    // Log4J does logging. We'll meet it properly in a later week...
+    implementation 'org.apache.logging.log4j:log4j-api:2.18.0'
+    implementation 'org.apache.logging.log4j:log4j-core:2.18.0'
+
+    testImplementation 'org.junit.jupiter:junit-jupiter-api:5.7.0'
+    testRuntimeOnly 'org.junit.jupiter:junit-jupiter-engine:5.7.0'
+}
+
+test {
+    useJUnitPlatform()
+}
+
+application {
+    mainClass = 'dotsandboxes.Main'
+}
+
+task fatJar(type: Jar) {
+    manifest {
+        attributes 'Main-Class': 'dotsandboxes.Main'
+    }
+    baseName = 'executable-jar'
+    duplicatesStrategy = DuplicatesStrategy.EXCLUDE
+    from { configurations.runtimeClasspath.collect { it.isDirectory() ? it : zipTree(it) } }
+    with jar
+}
\ No newline at end of file

gradle/wrapper/gradle-wrapper.properties

+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.3.1-bin.zip
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/master/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+APP_HOME=$( cd "${APP_HOME:-./}" && pwd -P ) || exit
+
+APP_NAME="Gradle"
+APP_BASE_NAME=${0##*/}
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+# Collect all arguments for the java command;
+#   * $DEFAULT_JVM_OPTS, $JAVA_OPTS, and $GRADLE_OPTS can contain fragments of
+#     shell script including quotes and variable substitutions, so put them in
+#     double quotes to make sure that they get re-expanded; and
+#   * put everything else in single quotes, so that it's not re-expanded.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle

+pluginManagement {
+    repositories {
+        maven { url "https://hopper.une.edu.au/artifactory/gradle-plugins/" }
+        gradlePluginPortal()
+    }
+}
+
+rootProject.name = 'dotsAndBoxes'
+

src/main/java/dotsandboxes/DotsAndBoxesGrid.java

+package dotsandboxes;
+
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.function.Consumer;
+
+/**
+ * The state of a dots and boxes grid.
+ *
+ * A (4, 3) dots and boxes grid looks like this:
+ *
+ * *-*-*-*
+ * | | | |
+ * *-*-*-*
+ * | | | |
+ * *-*-*-*
+ *
+ * Notice that:
+ *
+ * - for each row, there is one less horizontal than the number of corner dots
+ * - for each row, there are as many verticals as there are corner dots
+ * - for each row, there is one less box than the number of corner dots
+ * - for each column, there is one less vertical than the number of corner dots.
+ * - for each column, there are as many horizontals as there are corner dots.
+ * - for each column, there is one less box than the number of corner dots
+ *
+ * For example, in this (4, 3) grid, there are (3, 3) horizontal lines, and (4, 2) vertical lines, and (3, 2) boxes.
+ *
+ * We number all lines and boxes by their top-left coordinate.
+ *
+ * In Java 14+, we might use a Record class for this, but we're using 11+ as an LTS version, so we don't have that yet.
+ */
+public class DotsAndBoxesGrid {
+
+    final int width;
+    final int height;
+
+    /** The horizontal lines in the grid. True if drawn. */
+    private boolean[][] horizontals;
+
+    /** The vertical lines in the grid. True if drawn. */
+    private boolean[][] verticals;
+
+    /** Which owner (if any) claimed any given box. */
+    private int[][] boxOwners;
+
+    /** A list of functions to notify when there is an update */
+    private ArrayList<Consumer<DotsAndBoxesGrid>> watchers = new ArrayList<>();
+
+    final int players;
+    private int player = 1;
+    public int getPlayer() {
+        return player;
+    }
+
+    /** Moves to the next player */
+    private void nextPlayer() {
+        player++;
+        if (player > players) {
+            player = 1;
+        }
+    }
+
+    public DotsAndBoxesGrid(int width, int height, int players) {
+        this.width = width;
+        this.height = height;
+        this.players = players;
+
+        this.horizontals = new boolean[width - 1][height];
+        this.verticals = new boolean[width][height - 1];
+        this.boxOwners = new int[width - 1][height - 1];
+    }
+
+    private void notifyObservers() {
+        for (Consumer<DotsAndBoxesGrid> consumer : watchers) {
+            consumer.accept(this);
+        }
+    }
+
+    /** Listens to this grid for changes */
+    public void addConsumer(Consumer<DotsAndBoxesGrid> consumer) {
+        watchers.add(consumer);
+    }
+
+    /** Returns whether a horizontal line has been drawn */
+    public boolean getHorizontal(int x, int y) {
+        return horizontals[x][y];
+    }
+
+    /** Returns whether a vertical line has been drawn */
+    public boolean getVertical(int x, int y) {
+        return verticals[x][y];
+    }
+
+    /** Returns which player owns a box. By convention, 0 is unowned. */
+    public int getBoxOwner(int x, int y) {
+        return boxOwners[x][y];
+    }
+
+
+    /**
+     * Checks whether a box has been fully drawn (all four sides)
+     * @param x coordinate of the left side of the box
+     * @param y coordinate of the top of the box
+     * @return true if all four sides have been drawn.
+     */
+    public boolean boxComplete(int x, int y) {
+        if (x >= width - 1 || x < 0 || y >= height - 1 || y < 0) {
+            return false;
+        }
+
+        // A box is complete if the north and south horizontals and the east and west verticals have all been drawn.
+        // FIXME: You'll need to fix this code (after writing a test first).
+        return true;
+    }
+
+    /** Tries to claim a box for a player. If the box is complete, sets the ownership and returns true. */
+    private boolean claimBox(int x, int y, int p) {
+        if (boxComplete(x, y)) {
+            boxOwners[x][y] = player;
+            return true;
+        } else {
+            return false;
+        }
+    }
+
+    /**
+     * "Draws" a horizontal line, from grid point (x, y) to (x + 1, y). (i.e. sets that line to true)
+     * @param x
+     * @param y
+     * @return true if it completes a box
+     */
+    public boolean drawHorizontal(int x, int y, int player) {
+        if (x >= width - 1 || x < 0) {
+            throw new IndexOutOfBoundsException(String.format("x was %d, which is out of range. Range is 0 to %d", x, width - 1));
+        }
+        if (y >= height || y < 0) {
+            throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height));
+        }
+
+        // FIXME: You need to throw an exception if the line was already drawn.
+
+        this.horizontals[x][y] = true;
+
+        // Try to claim the north or south boxes
+        boolean claimN = claimBox(x, y-1, player);
+        boolean claimS = claimBox(x, y, player);
+        if (claimN || claimS) {
+            notifyObservers();
+            return true;
+        } else {
+            nextPlayer();
+            notifyObservers();
+            return false;
+        }
+    }
+
+    /**
+     * "Draws" a vertical line, from grid point (x, y) to (x, y + 1). (i.e. sets that line to true)
+     * @param x
+     * @param y
+     * @return true if it completes a box
+     */
+    public boolean drawVertical(int x, int y, int player) {
+        if (x >= width || x < 0) {
+            throw new IndexOutOfBoundsException(String.format("x was %d, which is out of range. Range is 0 to %d", x, width));
+        }
+        if (y >= height - 1 || y < 0) {
+            throw new IndexOutOfBoundsException(String.format("y was %d, which is out of range. Range is 0 to %d", y, height - 1));
+        }
+
+        // You need to throw an exception if the line was already drawn.
+
+        this.verticals[x][y] = true;
+        // Try to claim the north or south boxes
+        boolean claimE = claimBox(x, y, player);
+        boolean claimW = claimBox(x-1, y, player);
+        if (claimE || claimW) {
+            notifyObservers();
+            return true;
+        } else {
+            nextPlayer();
+            notifyObservers();
+            return false;
+        }
+
+    }
+
+    public boolean gameComplete() {
+        // Students who took COSC250 might recognise this style of code. This is Java's version of higher order functions.
+        // The grid is complete if "for all rows, all the boxes in that row have a non-zero owner"
+        return Arrays.stream(boxOwners).allMatch((row) -> Arrays.stream(row).allMatch((owner) -> owner > 0));
+    }
+
+
+}

src/main/java/dotsandboxes/DotsAndBoxesUI.java

+package dotsandboxes;
+
+import java.awt.*;
+import java.awt.event.*;
+import javax.swing.*;
+import javax.swing.event.MouseInputAdapter;
+import java.util.ArrayList;
+
+public class DotsAndBoxesUI {
+
+    static final int lineLength = 32;
+    static final int margin = 10;
+    static final int gap = 0;
+    static final int dotDiameter = 6;
+
+    // The coordinate of the top or left of a the painting area for this row/col
+    private static int corner(int col) {
+        return margin + col * (gap + lineLength + gap + dotDiameter);
+    }
+
+    /** Colours for the different players. Only goes up to 5. */
+    static final Color[] playerColours = { Color.WHITE, Color.RED, Color.BLUE, Color.GREEN, Color.PINK, Color.ORANGE };
+
+    final DotsAndBoxesGrid grid;
+    final JPanel anchorPane;
+    final Canvas canvas;
+    final JLabel label;
+
+    private void updateLabel() {
+        label.setForeground(playerColours[grid.getPlayer()]);
+        label.setText(String.format("Player %d's turn", grid.getPlayer()));
+    }
+
+    public DotsAndBoxesUI(final DotsAndBoxesGrid grid) {
+        this.grid = grid;
+        anchorPane = new JPanel(new BorderLayout());
+
+        label = new JLabel("");
+        updateLabel();
+
+        canvas = new DABCanvas();
+
+        anchorPane.add(canvas, BorderLayout.CENTER);
+        anchorPane.add(label, BorderLayout.NORTH);
+
+        grid.addConsumer((g) -> {
+            updateLabel();
+            canvas.repaint();
+        });
+    }
+
+    /** A component that paints and handles clicks on the game */
+    class DABCanvas extends Canvas {
+
+        final ArrayList<Horizontal> horizontals = new ArrayList<>();
+        final ArrayList<Vertical> verticals = new ArrayList<>();
+        final ArrayList<Box> boxes = new ArrayList<>();
+
+        /** Represents a horizontal line. */
+        record Horizontal(int col, int row) {
+            Rectangle rect() {
+                int x = corner(col) + dotDiameter + gap;
+                int y = corner(row);
+                return new Rectangle(x, y, lineLength, dotDiameter);
+            }
+
+            /** Whether or not this line contains this point */
+            boolean contains(int x, int y) {
+                return rect().contains(x, y);
+            }
+
+            /** Paints this element, based on the passed in grid */
+            public void draw(DotsAndBoxesGrid grid, Graphics2D g2d) {
+                g2d.setColor(grid.getHorizontal(col, row) ? Color.DARK_GRAY : Color.LIGHT_GRAY);
+                g2d.fill(this.rect());
+            }
+        }
+
+        /** Represents a horizontal line. */
+        record Vertical(int col, int row) {
+            Rectangle rect() {
+                int x = corner(col);
+                int y = corner(row) + dotDiameter + gap;
+                return new Rectangle(x, y, dotDiameter, lineLength);
+            }
+
+            /** Whether or not this line contains this point */
+            boolean contains(int x, int y) {
+                return rect().contains(x, y);
+            }
+
+            /** Paints this element, based on the passed in grid */
+            public void draw(DotsAndBoxesGrid grid, Graphics2D g2d) {
+                g2d.setColor(grid.getVertical(col, row) ? Color.DARK_GRAY : Color.LIGHT_GRAY);
+                g2d.fill(this.rect());
+            }
+        }
+
+        /** represents a box */
+        record Box(int col, int row) {
+            Rectangle rect() {
+                int x = corner(col) + dotDiameter + gap;
+                int y = corner(row) + dotDiameter + gap;
+                return new Rectangle(x, y, lineLength, lineLength);
+            }
+
+            /** Whether or not this line contains this point */
+            boolean contains(int x, int y) {
+                return rect().contains(x, y);
+            }
+
+            /** Paints this element, based on the passed in grid */
+            public void draw(DotsAndBoxesGrid grid, Graphics2D g2d) {
+                g2d.setColor(playerColours[grid.getBoxOwner(col, row)]);
+                g2d.fill(this.rect());
+            }
+        }
+
+
+        public DABCanvas() {
+            // Size the canvas to just contain the elements
+            int width = corner(grid.width) + margin;
+            int height = corner(grid.height) + margin;
+            this.setPreferredSize(new Dimension(width, height));
+
+            // Create records for the boxes
+            for (int row = 0; row < grid.height - 1; row++) {
+                for (int col = 0; col < grid.width - 1; col++) {
+                    boxes.add(new Box(col, row));
+                }
+            }
+
+            // Create records for horizontals
+            for (int row = 0; row < grid.height; row++) {
+                for (int col = 0; col < grid.width - 1; col++) {
+                    horizontals.add(new Horizontal(col, row));
+                }
+            }
+
+            // Create records for verticals
+            for (int row = 0; row < grid.height - 1; row++) {
+                for (int col = 0; col < grid.width; col++) {
+                    verticals.add(new Vertical(col, row));
+                }
+            }
+
+            addMouseListener(new MouseInputAdapter() {
+                @Override public void mousePressed(MouseEvent e) {
+                    for (Horizontal h : horizontals) {
+                        if (h.contains(e.getX(), e.getY())) {
+                            grid.drawHorizontal(h.col(), h.row(), grid.getPlayer());
+                        }
+                    }
+
+                    for (Vertical v : verticals) {
+                        if (v.contains(e.getX(), e.getY())) {
+                            grid.drawVertical(v.col(), v.row(), grid.getPlayer());
+                        }
+                    }
+                }        
+            });
+
+        }
+
+        @Override public void paint(Graphics g) {
+            Graphics2D g2d = (Graphics2D)g;
+            g.clearRect(0, 0, this.getWidth(), this.getHeight());
+            g2d.setColor(Color.WHITE);
+            g.fillRect(0, 0, this.getWidth(), this.getHeight());
+
+            // Paint the boxes
+            for (Box b : boxes) {
+                b.draw(grid, g2d);
+            }
+
+            // Paint the horizontals
+            for (Horizontal h : horizontals) {
+                h.draw(grid, g2d);
+            }
+
+            // Paint the boxes
+            for (Vertical v : verticals) {
+                v.draw(grid, g2d);
+            }
+
+            // Draw the dots
+            for (int row = 0; row < grid.height; row++) {
+                for (int col = 0; col < grid.width; col++) {
+                    g2d.setColor(Color.BLACK);
+                    g2d.fillOval(corner(col), corner(row), dotDiameter, dotDiameter);
+                }
+            }
+        }
+
+    }
+
+
+
+
+}

src/main/java/dotsandboxes/Main.java

+package dotsandboxes;
+
+import javax.swing.*;
+import java.awt.*;
+
+/** Our main class that launches the app. */
+public class Main {
+    
+    public static void main(String... args) throws Exception {
+
+        JFrame mainWindow = new JFrame("Dots and Boxes");
+        DotsAndBoxesGrid grid = new DotsAndBoxesGrid(15, 8, 2);
+
+        // FIXME: Update this label to show your name and student number
+        JLabel label = new JLabel("Name: Aarati Bhattarai");
+
+        JPanel borderPane = new JPanel(new BorderLayout());
+        borderPane.add(label, BorderLayout.SOUTH);
+
+        DotsAndBoxesUI dbUi = new DotsAndBoxesUI(grid);
+        borderPane.add(dbUi.anchorPane, BorderLayout.CENTER);
+        borderPane.add(dbUi.label, BorderLayout.NORTH);
+        mainWindow.add(borderPane);
+
+        mainWindow.pack();
+        mainWindow.setVisible(true);
+
+        // This sets what to do when we close the main window.
+        mainWindow.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
+    }
+
+}

src/test/java/dotsandboxes/DotsAndBoxesGridTest.java

+package dotsandboxes;
+
+import org.junit.jupiter.api.*;
+import static org.junit.jupiter.api.Assertions.*;
+import static org.junit.jupiter.api.Assumptions.*;
+
+import org.apache.logging.log4j.LogManager;
+import org.apache.logging.log4j.Logger;
+
+public class DotsAndBoxesGridTest {
+    /*
+     * Because Test classes are classes, they can have fields, and can have static fields.
+     * This field is a logger. Loggers are like a more advanced println, for writing messages out to the console or a log file.
+     */
+    private static final Logger logger = LogManager.getLogger(DotsAndBoxesGridTest.class);
+
+    /*
+     * Tests are functions that have an @Test annotation before them.
+     * The typical format of a test is that it contains some code that does something, and then one
+     * or more assertions to check that a condition holds.
+     *
+     * This is a dummy test just to show that the test suite itself runs
+     */
+    @Test
+    public void testTestSuiteRuns() {
+        logger.info("Dummy test to show the test suite runs");
+        assertTrue(true);
+    }
+
+    // FIXME: You need to write tests for the two known bugs in the code.
+}

src/test/resources/log4j2.xml

+<?xml version="1.0" encoding="UTF-8"?>
+<Configuration status="WARN">
+    <Appenders>
+        <Console name="Console" target="SYSTEM_OUT">
+            <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
+        </Console>
+    </Appenders>
+    <Loggers>
+        <Root level="debug">
+            <AppenderRef ref="Console"/>
+        </Root>
+    </Loggers>
+</Configuration>
\ No newline at end of file