Initial commit

tapas-tasks/.editorconfig

@@ -0,0 +1,9 @@
+root = true
+
+[*]
+charset = utf-8
+indent_style = space
+indent_size = 4
+trim_trailing_whitespace = true
+end_of_line = lf
+insert_final_newline = true

tapas-tasks/.gitignore

@@ -0,0 +1,33 @@
+HELP.md
+target/
+!.mvn/wrapper/maven-wrapper.jar
+!**/src/main/**/target/
+!**/src/test/**/target/
+
+### STS ###
+.apt_generated
+.classpath
+.factorypath
+.project
+.settings
+.springBeans
+.sts4-cache
+
+### IntelliJ IDEA ###
+.idea
+*.iws
+*.iml
+*.ipr
+
+### NetBeans ###
+/nbproject/private/
+/nbbuild/
+/dist/
+/nbdist/
+/.nb-gradle/
+build/
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+### VS Code ###
+.vscode/

tapas-tasks/.mvn/wrapper/MavenWrapperDownloader.java

@@ -0,0 +1,117 @@
+/*
+ * Copyright 2007-present the original author or 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.
+ */
+import java.net.*;
+import java.io.*;
+import java.nio.channels.*;
+import java.util.Properties;
+
+public class MavenWrapperDownloader {
+
+    private static final String WRAPPER_VERSION = "0.5.6";
+    /**
+     * Default URL to download the maven-wrapper.jar from, if no 'downloadUrl' is provided.
+     */
+    private static final String DEFAULT_DOWNLOAD_URL = "https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/"
+        + WRAPPER_VERSION + "/maven-wrapper-" + WRAPPER_VERSION + ".jar";
+
+    /**
+     * Path to the maven-wrapper.properties file, which might contain a downloadUrl property to
+     * use instead of the default one.
+     */
+    private static final String MAVEN_WRAPPER_PROPERTIES_PATH =
+            ".mvn/wrapper/maven-wrapper.properties";
+
+    /**
+     * Path where the maven-wrapper.jar will be saved to.
+     */
+    private static final String MAVEN_WRAPPER_JAR_PATH =
+            ".mvn/wrapper/maven-wrapper.jar";
+
+    /**
+     * Name of the property which should be used to override the default download url for the wrapper.
+     */
+    private static final String PROPERTY_NAME_WRAPPER_URL = "wrapperUrl";
+
+    public static void main(String args[]) {
+        System.out.println("- Downloader started");
+        File baseDirectory = new File(args[0]);
+        System.out.println("- Using base directory: " + baseDirectory.getAbsolutePath());
+
+        // If the maven-wrapper.properties exists, read it and check if it contains a custom
+        // wrapperUrl parameter.
+        File mavenWrapperPropertyFile = new File(baseDirectory, MAVEN_WRAPPER_PROPERTIES_PATH);
+        String url = DEFAULT_DOWNLOAD_URL;
+        if(mavenWrapperPropertyFile.exists()) {
+            FileInputStream mavenWrapperPropertyFileInputStream = null;
+            try {
+                mavenWrapperPropertyFileInputStream = new FileInputStream(mavenWrapperPropertyFile);
+                Properties mavenWrapperProperties = new Properties();
+                mavenWrapperProperties.load(mavenWrapperPropertyFileInputStream);
+                url = mavenWrapperProperties.getProperty(PROPERTY_NAME_WRAPPER_URL, url);
+            } catch (IOException e) {
+                System.out.println("- ERROR loading '" + MAVEN_WRAPPER_PROPERTIES_PATH + "'");
+            } finally {
+                try {
+                    if(mavenWrapperPropertyFileInputStream != null) {
+                        mavenWrapperPropertyFileInputStream.close();
+                    }
+                } catch (IOException e) {
+                    // Ignore ...
+                }
+            }
+        }
+        System.out.println("- Downloading from: " + url);
+
+        File outputFile = new File(baseDirectory.getAbsolutePath(), MAVEN_WRAPPER_JAR_PATH);
+        if(!outputFile.getParentFile().exists()) {
+            if(!outputFile.getParentFile().mkdirs()) {
+                System.out.println(
+                        "- ERROR creating output directory '" + outputFile.getParentFile().getAbsolutePath() + "'");
+            }
+        }
+        System.out.println("- Downloading to: " + outputFile.getAbsolutePath());
+        try {
+            downloadFileFromURL(url, outputFile);
+            System.out.println("Done");
+            System.exit(0);
+        } catch (Throwable e) {
+            System.out.println("- Error downloading");
+            e.printStackTrace();
+            System.exit(1);
+        }
+    }
+
+    private static void downloadFileFromURL(String urlString, File destination) throws Exception {
+        if (System.getenv("MVNW_USERNAME") != null && System.getenv("MVNW_PASSWORD") != null) {
+            String username = System.getenv("MVNW_USERNAME");
+            char[] password = System.getenv("MVNW_PASSWORD").toCharArray();
+            Authenticator.setDefault(new Authenticator() {
+                @Override
+                protected PasswordAuthentication getPasswordAuthentication() {
+                    return new PasswordAuthentication(username, password);
+                }
+            });
+        }
+        URL website = new URL(urlString);
+        ReadableByteChannel rbc;
+        rbc = Channels.newChannel(website.openStream());
+        FileOutputStream fos = new FileOutputStream(destination);
+        fos.getChannel().transferFrom(rbc, 0, Long.MAX_VALUE);
+        fos.close();
+        rbc.close();
+    }
+
+}

tapas-tasks/.mvn/wrapper/maven-wrapper.properties

@@ -0,0 +1,2 @@
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.1/apache-maven-3.8.1-bin.zip
+wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

tapas-tasks/README.md

@@ -0,0 +1,71 @@
+# tapas-tasks
+
+Micro-service for Managing Tasks in a Task List implemented following Hexagonal Architecture.
+
+Based on examples from book "Get Your Hands Dirty on Clean Architecture" by Tom Hombergs
+
+Technologies: Java, Spring Boot, Maven
+
+**Note:** this repository contains an [EditorConfig](https://editorconfig.org/) file (`.editorconfig`)
+with default editor settings. EditorConfig is supported out-of-the-box by the IntelliJ IDE. To help maintain
+consistent code styles, we recommend to reuse this editor configuration file in all your services.
+
+## HTTP API Overview
+The code we provide includes a minimalistic HTTP API for (i) creating a new task and (ii) retrieving
+the representation of a task.
+
+For further developing and working with your HTTP API, we recommend to use [Postman](https://www.postman.com/).
+
+### Creating a new task
+
+A new task is created via an `HTTP POST` request to the `/tasks/` endpoint. The body of the request
+must include a JSON payload with the content type `application/json` and two required fields:
+* `taskName`: a string that represents the name of the task to be created
+* `taskType`: a string that represents the type of the task to be created
+
+A sample HTTP request with `curl`:
+```shell
+curl -i --location --request POST 'http://localhost:8081/tasks/' --header 'Content-Type: application/json' --data-raw '{
+    "taskName" : "task1",
+    "taskType" : "type1"
+}'
+
+HTTP/1.1 201
+Content-Type: application/json
+Content-Length: 142
+Date: Sun, 03 Oct 2021 17:25:32 GMT
+
+{
+  "taskType" : "type1",
+  "taskState" : "OPEN",
+  "taskListName" : "tapas-tasks-tutors",
+  "taskName" : "task1",
+  "taskId" : "53cb19d6-2d9b-486f-98c7-c96c93b037f0"
+}
+```
+
+If the task is created successfuly, a `201 Created` status code is returned together with a JSON
+representation of the created task. The representation includes, among others, a _universally unique
+identifier (UUID)_ for the newly created task (`taskId`).
+
+### Retrieving a task
+
+The representation of a task is retrieved via an `HTTP GET` request to the `/tasks/<task-UUID>` endpoint.
+
+A sample HTTP request with `curl`:
+```shell
+curl -i --location --request GET 'http://localhost:8081/tasks/53cb19d6-2d9b-486f-98c7-c96c93b037f0'
+
+HTTP/1.1 200
+Content-Type: application/json
+Content-Length: 142
+Date: Sun, 03 Oct 2021 17:27:06 GMT
+
+{
+  "taskType" : "type1",
+  "taskState" : "OPEN",
+  "taskListName" : "tapas-tasks-tutors",
+  "taskName" : "task1",
+  "taskId" : "53cb19d6-2d9b-486f-98c7-c96c93b037f0"
+}
+```

tapas-tasks/mvnw

@@ -0,0 +1,310 @@
+#!/bin/sh
+# ----------------------------------------------------------------------------
+# Licensed to the Apache Software Foundation (ASF) under one
+# or more contributor license agreements.  See the NOTICE file
+# distributed with this work for additional information
+# regarding copyright ownership.  The ASF licenses this file
+# to you 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.
+# ----------------------------------------------------------------------------
+
+# ----------------------------------------------------------------------------
+# Maven Start Up Batch script
+#
+# Required ENV vars:
+# ------------------
+#   JAVA_HOME - location of a JDK home dir
+#
+# Optional ENV vars
+# -----------------
+#   M2_HOME - location of maven2's installed home dir
+#   MAVEN_OPTS - parameters passed to the Java VM when running Maven
+#     e.g. to debug Maven itself, use
+#       set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+#   MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+# ----------------------------------------------------------------------------
+
+if [ -z "$MAVEN_SKIP_RC" ] ; then
+
+  if [ -f /etc/mavenrc ] ; then
+    . /etc/mavenrc
+  fi
+
+  if [ -f "$HOME/.mavenrc" ] ; then
+    . "$HOME/.mavenrc"
+  fi
+
+fi
+
+# OS specific support.  $var _must_ be set to either true or false.
+cygwin=false;
+darwin=false;
+mingw=false
+case "`uname`" in
+  CYGWIN*) cygwin=true ;;
+  MINGW*) mingw=true;;
+  Darwin*) darwin=true
+    # Use /usr/libexec/java_home if available, otherwise fall back to /Library/Java/Home
+    # See https://developer.apple.com/library/mac/qa/qa1170/_index.html
+    if [ -z "$JAVA_HOME" ]; then
+      if [ -x "/usr/libexec/java_home" ]; then
+        export JAVA_HOME="`/usr/libexec/java_home`"
+      else
+        export JAVA_HOME="/Library/Java/Home"
+      fi
+    fi
+    ;;
+esac
+
+if [ -z "$JAVA_HOME" ] ; then
+  if [ -r /etc/gentoo-release ] ; then
+    JAVA_HOME=`java-config --jre-home`
+  fi
+fi
+
+if [ -z "$M2_HOME" ] ; then
+  ## resolve links - $0 may be a link to maven's home
+  PRG="$0"
+
+  # need this for relative symlinks
+  while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+      PRG="$link"
+    else
+      PRG="`dirname "$PRG"`/$link"
+    fi
+  done
+
+  saveddir=`pwd`
+
+  M2_HOME=`dirname "$PRG"`/..
+
+  # make it fully qualified
+  M2_HOME=`cd "$M2_HOME" && pwd`
+
+  cd "$saveddir"
+  # echo Using m2 at $M2_HOME
+fi
+
+# For Cygwin, ensure paths are in UNIX format before anything is touched
+if $cygwin ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --unix "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --unix "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --unix "$CLASSPATH"`
+fi
+
+# For Mingw, ensure paths are in UNIX format before anything is touched
+if $mingw ; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME="`(cd "$M2_HOME"; pwd)`"
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME="`(cd "$JAVA_HOME"; pwd)`"
+fi
+
+if [ -z "$JAVA_HOME" ]; then
+  javaExecutable="`which javac`"
+  if [ -n "$javaExecutable" ] && ! [ "`expr \"$javaExecutable\" : '\([^ ]*\)'`" = "no" ]; then
+    # readlink(1) is not available as standard on Solaris 10.
+    readLink=`which readlink`
+    if [ ! `expr "$readLink" : '\([^ ]*\)'` = "no" ]; then
+      if $darwin ; then
+        javaHome="`dirname \"$javaExecutable\"`"
+        javaExecutable="`cd \"$javaHome\" && pwd -P`/javac"
+      else
+        javaExecutable="`readlink -f \"$javaExecutable\"`"
+      fi
+      javaHome="`dirname \"$javaExecutable\"`"
+      javaHome=`expr "$javaHome" : '\(.*\)/bin'`
+      JAVA_HOME="$javaHome"
+      export JAVA_HOME
+    fi
+  fi
+fi
+
+if [ -z "$JAVACMD" ] ; then
+  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
+  else
+    JAVACMD="`which java`"
+  fi
+fi
+
+if [ ! -x "$JAVACMD" ] ; then
+  echo "Error: JAVA_HOME is not defined correctly." >&2
+  echo "  We cannot execute $JAVACMD" >&2
+  exit 1
+fi
+
+if [ -z "$JAVA_HOME" ] ; then
+  echo "Warning: JAVA_HOME environment variable is not set."
+fi
+
+CLASSWORLDS_LAUNCHER=org.codehaus.plexus.classworlds.launcher.Launcher
+
+# traverses directory structure from process work directory to filesystem root
+# first directory with .mvn subdirectory is considered project base directory
+find_maven_basedir() {
+
+  if [ -z "$1" ]
+  then
+    echo "Path not specified to find_maven_basedir"
+    return 1
+  fi
+
+  basedir="$1"
+  wdir="$1"
+  while [ "$wdir" != '/' ] ; do
+    if [ -d "$wdir"/.mvn ] ; then
+      basedir=$wdir
+      break
+    fi
+    # workaround for JBEAP-8937 (on Solaris 10/Sparc)
+    if [ -d "${wdir}" ]; then
+      wdir=`cd "$wdir/.."; pwd`
+    fi
+    # end of workaround
+  done
+  echo "${basedir}"
+}
+
+# concatenates all lines of a file
+concat_lines() {
+  if [ -f "$1" ]; then
+    echo "$(tr -s '\n' ' ' < "$1")"
+  fi
+}
+
+BASE_DIR=`find_maven_basedir "$(pwd)"`
+if [ -z "$BASE_DIR" ]; then
+  exit 1;
+fi
+
+##########################################################################################
+# Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+# This allows using the maven wrapper in projects that prohibit checking in binary data.
+##########################################################################################
+if [ -r "$BASE_DIR/.mvn/wrapper/maven-wrapper.jar" ]; then
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Found .mvn/wrapper/maven-wrapper.jar"
+    fi
+else
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Couldn't find .mvn/wrapper/maven-wrapper.jar, downloading it ..."
+    fi
+    if [ -n "$MVNW_REPOURL" ]; then
+      jarUrl="$MVNW_REPOURL/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    else
+      jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    fi
+    while IFS="=" read key value; do
+      case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
+      esac
+    done < "$BASE_DIR/.mvn/wrapper/maven-wrapper.properties"
+    if [ "$MVNW_VERBOSE" = true ]; then
+      echo "Downloading from: $jarUrl"
+    fi
+    wrapperJarPath="$BASE_DIR/.mvn/wrapper/maven-wrapper.jar"
+    if $cygwin; then
+      wrapperJarPath=`cygpath --path --windows "$wrapperJarPath"`
+    fi
+
+    if command -v wget > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found wget ... using wget"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            wget "$jarUrl" -O "$wrapperJarPath"
+        else
+            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath"
+        fi
+    elif command -v curl > /dev/null; then
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Found curl ... using curl"
+        fi
+        if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
+            curl -o "$wrapperJarPath" "$jarUrl" -f
+        else
+            curl --user $MVNW_USERNAME:$MVNW_PASSWORD -o "$wrapperJarPath" "$jarUrl" -f
+        fi
+
+    else
+        if [ "$MVNW_VERBOSE" = true ]; then
+          echo "Falling back to using Java to download"
+        fi
+        javaClass="$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.java"
+        # For Cygwin, switch paths to Windows format before running javac
+        if $cygwin; then
+          javaClass=`cygpath --path --windows "$javaClass"`
+        fi
+        if [ -e "$javaClass" ]; then
+            if [ ! -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Compiling MavenWrapperDownloader.java ..."
+                fi
+                # Compiling the Java class
+                ("$JAVA_HOME/bin/javac" "$javaClass")
+            fi
+            if [ -e "$BASE_DIR/.mvn/wrapper/MavenWrapperDownloader.class" ]; then
+                # Running the downloader
+                if [ "$MVNW_VERBOSE" = true ]; then
+                  echo " - Running MavenWrapperDownloader.java ..."
+                fi
+                ("$JAVA_HOME/bin/java" -cp .mvn/wrapper MavenWrapperDownloader "$MAVEN_PROJECTBASEDIR")
+            fi
+        fi
+    fi
+fi
+##########################################################################################
+# End of extension
+##########################################################################################
+
+export MAVEN_PROJECTBASEDIR=${MAVEN_BASEDIR:-"$BASE_DIR"}
+if [ "$MVNW_VERBOSE" = true ]; then
+  echo $MAVEN_PROJECTBASEDIR
+fi
+MAVEN_OPTS="$(concat_lines "$MAVEN_PROJECTBASEDIR/.mvn/jvm.config") $MAVEN_OPTS"
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin; then
+  [ -n "$M2_HOME" ] &&
+    M2_HOME=`cygpath --path --windows "$M2_HOME"`
+  [ -n "$JAVA_HOME" ] &&
+    JAVA_HOME=`cygpath --path --windows "$JAVA_HOME"`
+  [ -n "$CLASSPATH" ] &&
+    CLASSPATH=`cygpath --path --windows "$CLASSPATH"`
+  [ -n "$MAVEN_PROJECTBASEDIR" ] &&
+    MAVEN_PROJECTBASEDIR=`cygpath --path --windows "$MAVEN_PROJECTBASEDIR"`
+fi
+
+# Provide a "standardized" way to retrieve the CLI args that will
+# work with both Windows and non-Windows executions.
+MAVEN_CMD_LINE_ARGS="$MAVEN_CONFIG $@"
+export MAVEN_CMD_LINE_ARGS
+
+WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+exec "$JAVACMD" \
+  $MAVEN_OPTS \
+  -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
+  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"

tapas-tasks/mvnw.cmd

@@ -0,0 +1,182 @@
+@REM ----------------------------------------------------------------------------
+@REM Licensed to the Apache Software Foundation (ASF) under one
+@REM or more contributor license agreements.  See the NOTICE file
+@REM distributed with this work for additional information
+@REM regarding copyright ownership.  The ASF licenses this file
+@REM to you under the Apache License, Version 2.0 (the
+@REM "License"); you may not use this file except in compliance
+@REM with the License.  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,
+@REM software distributed under the License is distributed on an
+@REM "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+@REM KIND, either express or implied.  See the License for the
+@REM specific language governing permissions and limitations
+@REM under the License.
+@REM ----------------------------------------------------------------------------
+
+@REM ----------------------------------------------------------------------------
+@REM Maven Start Up Batch script
+@REM
+@REM Required ENV vars:
+@REM JAVA_HOME - location of a JDK home dir
+@REM
+@REM Optional ENV vars
+@REM M2_HOME - location of maven2's installed home dir
+@REM MAVEN_BATCH_ECHO - set to 'on' to enable the echoing of the batch commands
+@REM MAVEN_BATCH_PAUSE - set to 'on' to wait for a keystroke before ending
+@REM MAVEN_OPTS - parameters passed to the Java VM when running Maven
+@REM     e.g. to debug Maven itself, use
+@REM set MAVEN_OPTS=-Xdebug -Xrunjdwp:transport=dt_socket,server=y,suspend=y,address=8000
+@REM MAVEN_SKIP_RC - flag to disable loading of mavenrc files
+@REM ----------------------------------------------------------------------------
+
+@REM Begin all REM lines with '@' in case MAVEN_BATCH_ECHO is 'on'
+@echo off
+@REM set title of command window
+title %0
+@REM enable echoing by setting MAVEN_BATCH_ECHO to 'on'
+@if "%MAVEN_BATCH_ECHO%" == "on"  echo %MAVEN_BATCH_ECHO%
+
+@REM set %HOME% to equivalent of $HOME
+if "%HOME%" == "" (set "HOME=%HOMEDRIVE%%HOMEPATH%")
+
+@REM Execute a user defined script before this one
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPre
+@REM check for pre script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_pre.bat" call "%HOME%\mavenrc_pre.bat"
+if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+:skipRcPre
+
+@setlocal
+
+set ERROR_CODE=0
+
+@REM To isolate internal variables from possible post scripts, we use another setlocal
+@setlocal
+
+@REM ==== START VALIDATION ====
+if not "%JAVA_HOME%" == "" goto OkJHome
+
+echo.
+echo Error: JAVA_HOME not found in your environment. >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+:OkJHome
+if exist "%JAVA_HOME%\bin\java.exe" goto init
+
+echo.
+echo Error: JAVA_HOME is set to an invalid directory. >&2
+echo JAVA_HOME = "%JAVA_HOME%" >&2
+echo Please set the JAVA_HOME variable in your environment to match the >&2
+echo location of your Java installation. >&2
+echo.
+goto error
+
+@REM ==== END VALIDATION ====
+
+:init
+
+@REM Find the project base dir, i.e. the directory that contains the folder ".mvn".
+@REM Fallback to current working directory if not found.
+
+set MAVEN_PROJECTBASEDIR=%MAVEN_BASEDIR%
+IF NOT "%MAVEN_PROJECTBASEDIR%"=="" goto endDetectBaseDir
+
+set EXEC_DIR=%CD%
+set WDIR=%EXEC_DIR%
+:findBaseDir
+IF EXIST "%WDIR%"\.mvn goto baseDirFound
+cd ..
+IF "%WDIR%"=="%CD%" goto baseDirNotFound
+set WDIR=%CD%
+goto findBaseDir
+
+:baseDirFound
+set MAVEN_PROJECTBASEDIR=%WDIR%
+cd "%EXEC_DIR%"
+goto endDetectBaseDir
+
+:baseDirNotFound
+set MAVEN_PROJECTBASEDIR=%EXEC_DIR%
+cd "%EXEC_DIR%"
+
+:endDetectBaseDir
+
+IF NOT EXIST "%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config" goto endReadAdditionalConfig
+
+@setlocal EnableExtensions EnableDelayedExpansion
+for /F "usebackq delims=" %%a in ("%MAVEN_PROJECTBASEDIR%\.mvn\jvm.config") do set JVM_CONFIG_MAVEN_PROPS=!JVM_CONFIG_MAVEN_PROPS! %%a
+@endlocal & set JVM_CONFIG_MAVEN_PROPS=%JVM_CONFIG_MAVEN_PROPS%
+
+:endReadAdditionalConfig
+
+SET MAVEN_JAVA_EXE="%JAVA_HOME%\bin\java.exe"
+set WRAPPER_JAR="%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.jar"
+set WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
+
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+
+FOR /F "tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+    IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
+)
+
+@REM Extension to allow automatically downloading the maven-wrapper.jar from Maven-central
+@REM This allows using the maven wrapper in projects that prohibit checking in binary data.
+if exist %WRAPPER_JAR% (
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Found %WRAPPER_JAR%
+    )
+) else (
+    if not "%MVNW_REPOURL%" == "" (
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+    )
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Couldn't find %WRAPPER_JAR%, downloading it ...
+        echo Downloading from: %DOWNLOAD_URL%
+    )
+
+    powershell -Command "&{"^
+		"$webclient = new-object System.Net.WebClient;"^
+		"if (-not ([string]::IsNullOrEmpty('%MVNW_USERNAME%') -and [string]::IsNullOrEmpty('%MVNW_PASSWORD%'))) {"^
+		"$webclient.Credentials = new-object System.Net.NetworkCredential('%MVNW_USERNAME%', '%MVNW_PASSWORD%');"^
+		"}"^
+		"[Net.ServicePointManager]::SecurityProtocol = [Net.SecurityProtocolType]::Tls12; $webclient.DownloadFile('%DOWNLOAD_URL%', '%WRAPPER_JAR%')"^
+		"}"
+    if "%MVNW_VERBOSE%" == "true" (
+        echo Finished downloading %WRAPPER_JAR%
+    )
+)
+@REM End of extension
+
+@REM Provide a "standardized" way to retrieve the CLI args that will
+@REM work with both Windows and non-Windows executions.
+set MAVEN_CMD_LINE_ARGS=%*
+
+%MAVEN_JAVA_EXE% %JVM_CONFIG_MAVEN_PROPS% %MAVEN_OPTS% %MAVEN_DEBUG_OPTS% -classpath %WRAPPER_JAR% "-Dmaven.multiModuleProjectDirectory=%MAVEN_PROJECTBASEDIR%" %WRAPPER_LAUNCHER% %MAVEN_CONFIG% %*
+if ERRORLEVEL 1 goto error
+goto end
+
+:error
+set ERROR_CODE=1
+
+:end
+@endlocal & set ERROR_CODE=%ERROR_CODE%
+
+if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+@REM check for post script, once with legacy .bat ending and once with .cmd ending
+if exist "%HOME%\mavenrc_post.bat" call "%HOME%\mavenrc_post.bat"
+if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+:skipRcPost
+
+@REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
+if "%MAVEN_BATCH_PAUSE%" == "on" pause
+
+if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+
+exit /B %ERROR_CODE%

tapas-tasks/pom.xml

@@ -0,0 +1,82 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>2.5.3</version>
+		<relativePath/> <!-- lookup parent from repository -->
+	</parent>
+	<groupId>ch.unisg</groupId>
+	<artifactId>tapas-tasks</artifactId>
+	<version>0.0.1-SNAPSHOT</version>
+	<name>tapas-tasks</name>
+	<description>TAPAS Tasks</description>
+	<properties>
+		<java.version>11</java.version>
+	</properties>
+	<dependencies>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>org.projectlombok</groupId>
+			<artifactId>lombok</artifactId>
+			<optional>true</optional>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-validation</artifactId>
+		</dependency>
+
+		<dependency>
+			<groupId>javax.transaction</groupId>
+			<artifactId>javax.transaction-api</artifactId>
+			<version>1.2</version>
+		</dependency>
+        <dependency>
+            <groupId>javax.validation</groupId>
+            <artifactId>validation-api</artifactId>
+            <version>1.1.0.Final</version>
+        </dependency>
+
+		<dependency>
+			<groupId>org.json</groupId>
+			<artifactId>json</artifactId>
+			<version>20210307</version>
+		</dependency>
+		<dependency>
+			<groupId>com.github.java-json-tools</groupId>
+			<artifactId>json-patch</artifactId>
+			<version>1.13</version>
+		</dependency>
+
+    </dependencies>
+
+	<build>
+		<plugins>
+			<plugin>
+				<groupId>org.springframework.boot</groupId>
+				<artifactId>spring-boot-maven-plugin</artifactId>
+				<configuration>
+					<excludes>
+						<exclude>
+							<groupId>org.projectlombok</groupId>
+							<artifactId>lombok</artifactId>
+						</exclude>
+					</excludes>
+				</configuration>
+			</plugin>
+		</plugins>
+	</build>
+
+</project>

tapas-tasks/src/main/java/ch/unisg/tapastasks/TapasTasksApplication.java

@@ -0,0 +1,17 @@
+package ch.unisg.tapastasks;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+import java.util.Collections;
+
+@SpringBootApplication
+public class TapasTasksApplication {
+
+	public static void main(String[] args) {
+
+		SpringApplication tapasTasksApp = new SpringApplication(TapasTasksApplication.class);
+		tapasTasksApp.run(args);
+	}
+
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/common/SelfValidating.java

@@ -0,0 +1,30 @@
+package ch.unisg.tapastasks.common;
+
+import javax.validation.ConstraintViolation;
+import javax.validation.ConstraintViolationException;
+import javax.validation.Validation;
+import javax.validation.Validator;
+import javax.validation.ValidatorFactory;
+import java.util.Set;
+
+public abstract class SelfValidating<T> {
+
+    private Validator validator;
+
+    public SelfValidating() {
+        ValidatorFactory factory = Validation.buildDefaultValidatorFactory();
+        validator = factory.getValidator();
+    }
+
+    /**
+     * Evaluates all Bean Validations on the attributes of this
+     * instance.
+     */
+    protected void validateSelf() {
+        Set<ConstraintViolation<T>> violations = validator.validate((T) this);
+        if (!violations.isEmpty()) {
+            throw new ConstraintViolationException(violations);
+        }
+    }
+}
+

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/adapter/in/web/AddNewTaskToTaskListWebController.java

@@ -0,0 +1,42 @@
+package ch.unisg.tapastasks.tasks.adapter.in.web;
+
+import ch.unisg.tapastasks.tasks.application.port.in.AddNewTaskToTaskListCommand;
+import ch.unisg.tapastasks.tasks.application.port.in.AddNewTaskToTaskListUseCase;
+import ch.unisg.tapastasks.tasks.domain.Task;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+import org.springframework.web.server.ResponseStatusException;
+
+import javax.validation.ConstraintViolationException;
+
+@RestController
+public class AddNewTaskToTaskListWebController {
+    private final AddNewTaskToTaskListUseCase addNewTaskToTaskListUseCase;
+
+    public AddNewTaskToTaskListWebController(AddNewTaskToTaskListUseCase addNewTaskToTaskListUseCase) {
+        this.addNewTaskToTaskListUseCase = addNewTaskToTaskListUseCase;
+    }
+
+    @PostMapping(path = "/tasks/", consumes = {TaskMediaType.TASK_MEDIA_TYPE})
+    public ResponseEntity<String> addNewTaskTaskToTaskList(@RequestBody Task task) {
+        try {
+            AddNewTaskToTaskListCommand command = new AddNewTaskToTaskListCommand(
+                    task.getTaskName(), task.getTaskType()
+            );
+
+            Task newTask = addNewTaskToTaskListUseCase.addNewTaskToTaskList(command);
+
+            // Add the content type as a response header
+            HttpHeaders responseHeaders = new HttpHeaders();
+            responseHeaders.add(HttpHeaders.CONTENT_TYPE, TaskMediaType.TASK_MEDIA_TYPE);
+
+            return new ResponseEntity<>(TaskMediaType.serialize(newTask), responseHeaders, HttpStatus.CREATED);
+        } catch (ConstraintViolationException e) {
+            throw new ResponseStatusException(HttpStatus.BAD_REQUEST, e.getMessage());
+        }
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/adapter/in/web/RetrieveTaskFromTaskListWebController.java

@@ -0,0 +1,40 @@
+package ch.unisg.tapastasks.tasks.adapter.in.web;
+
+import ch.unisg.tapastasks.tasks.application.port.in.RetrieveTaskFromTaskListCommand;
+import ch.unisg.tapastasks.tasks.application.port.in.RetrieveTaskFromTaskListUseCase;
+import ch.unisg.tapastasks.tasks.domain.Task;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+import org.springframework.web.server.ResponseStatusException;
+
+import java.util.Optional;
+
+@RestController
+public class RetrieveTaskFromTaskListWebController {
+    private final RetrieveTaskFromTaskListUseCase retrieveTaskFromTaskListUseCase;
+
+    public RetrieveTaskFromTaskListWebController(RetrieveTaskFromTaskListUseCase retrieveTaskFromTaskListUseCase) {
+        this.retrieveTaskFromTaskListUseCase = retrieveTaskFromTaskListUseCase;
+    }
+
+    @GetMapping(path = "/tasks/{taskId}")
+    public ResponseEntity<String> retrieveTaskFromTaskList(@PathVariable("taskId") String taskId) {
+        RetrieveTaskFromTaskListCommand command = new RetrieveTaskFromTaskListCommand(new Task.TaskId(taskId));
+        Optional<Task> updatedTaskOpt = retrieveTaskFromTaskListUseCase.retrieveTaskFromTaskList(command);
+
+        // Check if the task with the given identifier exists
+        if (updatedTaskOpt.isEmpty()) {
+            // If not, through a 404 Not Found status code
+            throw new ResponseStatusException(HttpStatus.NOT_FOUND);
+        }
+
+        // Add the content type as a response header
+        HttpHeaders responseHeaders = new HttpHeaders();
+        responseHeaders.add(HttpHeaders.CONTENT_TYPE, TaskMediaType.TASK_MEDIA_TYPE);
+
+        return new ResponseEntity<>(TaskMediaType.serialize(updatedTaskOpt.get()), responseHeaders,
+                HttpStatus.OK);
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/adapter/in/web/TaskMediaType.java

@@ -0,0 +1,23 @@
+package ch.unisg.tapastasks.tasks.adapter.in.web;
+
+import ch.unisg.tapastasks.tasks.domain.Task;
+import ch.unisg.tapastasks.tasks.domain.TaskList;
+import org.json.JSONObject;
+
+final public class TaskMediaType {
+    public static final String TASK_MEDIA_TYPE = "application/json";
+
+    public static String serialize(Task task) {
+        JSONObject payload = new JSONObject();
+
+        payload.put("taskId", task.getTaskId().getValue());
+        payload.put("taskName", task.getTaskName().getValue());
+        payload.put("taskType", task.getTaskType().getValue());
+        payload.put("taskState", task.getTaskState().getValue());
+        payload.put("taskListName", TaskList.getTapasTaskList().getTaskListName().getValue());
+
+        return payload.toString();
+    }
+
+    private TaskMediaType() { }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/adapter/out/web/PublishNewTaskAddedEventWebAdapter.java

@@ -0,0 +1,58 @@
+package ch.unisg.tapastasks.tasks.adapter.out.web;
+
+import ch.unisg.tapastasks.tasks.application.port.out.NewTaskAddedEventPort;
+import ch.unisg.tapastasks.tasks.domain.NewTaskAddedEvent;
+import com.fasterxml.jackson.core.JsonProcessingException;
+import com.fasterxml.jackson.databind.ObjectMapper;
+import org.springframework.context.annotation.Primary;
+import org.springframework.stereotype.Component;
+
+import java.io.IOException;
+import java.net.URI;
+import java.net.http.HttpClient;
+import java.net.http.HttpRequest;
+import java.net.http.HttpResponse;
+import java.util.HashMap;
+
+@Component
+@Primary
+public class PublishNewTaskAddedEventWebAdapter implements NewTaskAddedEventPort {
+
+    //This is the base URI of the service interested in this event (in my setup, running locally as separate Spring Boot application)
+    String server = "http://127.0.0.1:8082";
+
+    @Override
+    public void publishNewTaskAddedEvent(NewTaskAddedEvent event) {
+
+        //Here we would need to work with DTOs in case the payload of calls becomes more complex
+
+        var values = new HashMap<String, String>() {{
+            put("taskname",event.taskName);
+            put("tasklist",event.taskListName);
+        }};
+
+        var objectMapper = new ObjectMapper();
+        String requestBody = null;
+        try {
+            requestBody = objectMapper.writeValueAsString(values);
+        } catch (JsonProcessingException e) {
+            e.printStackTrace();
+        }
+
+        HttpClient client = HttpClient.newHttpClient();
+        HttpRequest request = HttpRequest.newBuilder()
+                .uri(URI.create(server+"/roster/newtask/"))
+                .POST(HttpRequest.BodyPublishers.ofString(requestBody))
+                .build();
+
+        /** Needs the other service running
+        try {
+            HttpResponse<String> response = client.send(request, HttpResponse.BodyHandlers.ofString());
+        } catch (IOException e) {
+            e.printStackTrace();
+        } catch (InterruptedException e) {
+            e.printStackTrace();
+        }
+         **/
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/port/in/AddNewTaskToTaskListCommand.java

@@ -0,0 +1,23 @@
+package ch.unisg.tapastasks.tasks.application.port.in;
+
+import ch.unisg.tapastasks.common.SelfValidating;
+import ch.unisg.tapastasks.tasks.domain.Task.TaskType;
+import ch.unisg.tapastasks.tasks.domain.Task.TaskName;
+import lombok.Value;
+
+import javax.validation.constraints.NotNull;
+
+@Value
+public class AddNewTaskToTaskListCommand extends SelfValidating<AddNewTaskToTaskListCommand> {
+    @NotNull
+    private final TaskName taskName;
+
+    @NotNull
+    private final TaskType taskType;
+
+    public AddNewTaskToTaskListCommand(TaskName taskName, TaskType taskType) {
+        this.taskName = taskName;
+        this.taskType = taskType;
+        this.validateSelf();
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/port/in/AddNewTaskToTaskListUseCase.java

@@ -0,0 +1,7 @@
+package ch.unisg.tapastasks.tasks.application.port.in;
+
+import ch.unisg.tapastasks.tasks.domain.Task;
+
+public interface AddNewTaskToTaskListUseCase {
+    Task addNewTaskToTaskList(AddNewTaskToTaskListCommand command);
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/port/in/RetrieveTaskFromTaskListCommand.java

@@ -0,0 +1,18 @@
+package ch.unisg.tapastasks.tasks.application.port.in;
+
+import ch.unisg.tapastasks.common.SelfValidating;
+import ch.unisg.tapastasks.tasks.domain.Task.TaskId;
+import lombok.Value;
+
+import javax.validation.constraints.NotNull;
+
+@Value
+public class RetrieveTaskFromTaskListCommand extends SelfValidating<RetrieveTaskFromTaskListCommand> {
+    @NotNull
+    private final TaskId taskId;
+
+    public RetrieveTaskFromTaskListCommand(TaskId taskId) {
+        this.taskId = taskId;
+        this.validateSelf();
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/port/in/RetrieveTaskFromTaskListUseCase.java

@@ -0,0 +1,9 @@
+package ch.unisg.tapastasks.tasks.application.port.in;
+
+import ch.unisg.tapastasks.tasks.domain.Task;
+
+import java.util.Optional;
+
+public interface RetrieveTaskFromTaskListUseCase {
+    Optional<Task> retrieveTaskFromTaskList(RetrieveTaskFromTaskListCommand command);
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/port/out/NewTaskAddedEventPort.java

@@ -0,0 +1,8 @@
+package ch.unisg.tapastasks.tasks.application.port.out;
+
+import ch.unisg.tapastasks.tasks.domain.NewTaskAddedEvent;
+
+public interface NewTaskAddedEventPort {
+
+    void publishNewTaskAddedEvent(NewTaskAddedEvent event);
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/service/AddNewTaskToTaskListService.java

@@ -0,0 +1,39 @@
+package ch.unisg.tapastasks.tasks.application.service;
+
+import ch.unisg.tapastasks.tasks.application.port.in.AddNewTaskToTaskListCommand;
+import ch.unisg.tapastasks.tasks.application.port.in.AddNewTaskToTaskListUseCase;
+import ch.unisg.tapastasks.tasks.application.port.out.NewTaskAddedEventPort;
+import ch.unisg.tapastasks.tasks.domain.Task;
+
+import ch.unisg.tapastasks.tasks.domain.NewTaskAddedEvent;
+import ch.unisg.tapastasks.tasks.domain.TaskList;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Component;
+import javax.transaction.Transactional;
+
+@RequiredArgsConstructor
+@Component
+@Transactional
+public class AddNewTaskToTaskListService implements AddNewTaskToTaskListUseCase {
+
+    private final NewTaskAddedEventPort newTaskAddedEventPort;
+
+    @Override
+    public Task addNewTaskToTaskList(AddNewTaskToTaskListCommand command) {
+        TaskList taskList = TaskList.getTapasTaskList();
+        Task newTask = taskList.addNewTaskWithNameAndType(command.getTaskName(), command.getTaskType());
+
+        //Here we are using the application service to emit the domain event to the outside of the bounded context.
+        //This event should be considered as a light-weight "integration event" to communicate with other services.
+        //Domain events are usually rather "fat". In our implementation we simplify at this point. In general, it is
+        //not recommended to emit a domain event via an application service! You should first emit the domain event in
+        //the core and then the integration event in the application layer.
+        if (newTask != null) {
+            NewTaskAddedEvent newTaskAdded = new NewTaskAddedEvent(newTask.getTaskName().getValue(),
+                    taskList.getTaskListName().getValue());
+            newTaskAddedEventPort.publishNewTaskAddedEvent(newTaskAdded);
+        }
+
+        return newTask;
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/application/service/RetrieveTaskFromTaskListService.java

@@ -0,0 +1,22 @@
+package ch.unisg.tapastasks.tasks.application.service;
+
+import ch.unisg.tapastasks.tasks.application.port.in.RetrieveTaskFromTaskListCommand;
+import ch.unisg.tapastasks.tasks.application.port.in.RetrieveTaskFromTaskListUseCase;
+import ch.unisg.tapastasks.tasks.domain.Task;
+import ch.unisg.tapastasks.tasks.domain.TaskList;
+import lombok.RequiredArgsConstructor;
+import org.springframework.stereotype.Component;
+
+import javax.transaction.Transactional;
+import java.util.Optional;
+
+@RequiredArgsConstructor
+@Component
+@Transactional
+public class RetrieveTaskFromTaskListService implements RetrieveTaskFromTaskListUseCase {
+    @Override
+    public Optional<Task> retrieveTaskFromTaskList(RetrieveTaskFromTaskListCommand command) {
+        TaskList taskList = TaskList.getTapasTaskList();
+        return taskList.retrieveTaskById(command.getTaskId());
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/domain/NewTaskAddedEvent.java

@@ -0,0 +1,12 @@
+package ch.unisg.tapastasks.tasks.domain;
+
+/**This is a domain event (these are usually much fatter)**/
+public class NewTaskAddedEvent {
+    public String taskName;
+    public String taskListName;
+
+    public NewTaskAddedEvent(String taskName, String taskListName) {
+        this.taskName = taskName;
+        this.taskListName = taskListName;
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/domain/Task.java

@@ -0,0 +1,59 @@
+package ch.unisg.tapastasks.tasks.domain;
+
+import lombok.Getter;
+import lombok.Setter;
+import lombok.Value;
+
+import java.util.UUID;
+
+/**This is a domain entity**/
+public class Task {
+    public enum State {
+        OPEN, ASSIGNED, RUNNING, EXECUTED
+    }
+
+    @Getter
+    private final TaskId taskId;
+
+    @Getter
+    private final TaskName taskName;
+
+    @Getter
+    private final TaskType taskType;
+
+    @Getter
+    private TaskState taskState;
+
+    public Task(TaskName taskName, TaskType taskType) {
+        this.taskName = taskName;
+        this.taskType = taskType;
+        this.taskState = new TaskState(State.OPEN);
+        this.taskId = new TaskId(UUID.randomUUID().toString());
+    }
+
+    protected static Task createTaskWithNameAndType(TaskName name, TaskType type) {
+        //This is a simple debug message to see that the request has reached the right method in the core
+        System.out.println("New Task: " + name.getValue() + " " + type.getValue());
+        return new Task(name,type);
+    }
+
+    @Value
+    public static class TaskId {
+        private String value;
+    }
+
+    @Value
+    public static class TaskName {
+        private String value;
+    }
+
+    @Value
+    public static class TaskState {
+        private State value;
+    }
+
+    @Value
+    public static class TaskType {
+        private String value;
+    }
+}

tapas-tasks/src/main/java/ch/unisg/tapastasks/tasks/domain/TaskList.java

@@ -0,0 +1,68 @@
+package ch.unisg.tapastasks.tasks.domain;
+
+import lombok.Getter;
+import lombok.Value;
+
+import javax.swing.text.html.Option;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
+
+
+/**This is our aggregate root**/
+public class TaskList {
+
+    @Getter
+    private final TaskListName taskListName;
+
+    @Getter
+    private final ListOfTasks listOfTasks;
+
+    //Note: We do not care about the management of task lists, there is only one within this service
+    //--> using the Singleton pattern here to make lives easy; we will later load it from a repo
+    //TODO change "tutors" to your group name ("groupx")
+    private static final TaskList taskList = new TaskList(new TaskListName("tapas-tasks-tutors"));
+
+    private TaskList(TaskListName taskListName) {
+        this.taskListName = taskListName;
+        this.listOfTasks = new ListOfTasks(new LinkedList<Task>());
+    }
+
+    public static TaskList getTapasTaskList() {
+        return taskList;
+    }
+
+    //Only the aggregate root is allowed to create new tasks and add them to the task list.
+    //Note: Here we could add some sophisticated invariants/business rules that the aggregate root checks
+    public Task addNewTaskWithNameAndType(Task.TaskName name, Task.TaskType type) {
+        Task newTask = Task.createTaskWithNameAndType(name,type);
+        listOfTasks.value.add(newTask);
+        //This is a simple debug message to see that the task list is growing with each new request
+        System.out.println("Number of tasks: "+listOfTasks.value.size());
+        //Here we would also publish a domain event to other entities in the core interested in this event.
+        //However, we skip this here as it makes the core even more complex (e.g., we have to implement a light-weight
+        //domain event publisher and subscribers (see "Implementing Domain-Driven Design by V. Vernon, pp. 296ff).
+        return newTask;
+    }
+
+    public Optional<Task> retrieveTaskById(Task.TaskId id) {
+        for (Task task : listOfTasks.value) {
+            if (task.getTaskId().getValue().equalsIgnoreCase(id.getValue())) {
+                return Optional.of(task);
+            }
+        }
+
+        return Optional.empty();
+    }
+
+    @Value
+    public static class TaskListName {
+        private String value;
+    }
+
+    @Value
+    public static class ListOfTasks {
+        private List<Task> value;
+    }
+
+}

tapas-tasks/src/main/resources/application.properties

@@ -0,0 +1 @@
+server.port=8081

tapas-tasks/src/test/java/ch/unisg/tapastasks/TapasTasksApplicationTests.java

@@ -0,0 +1,13 @@
+package ch.unisg.tapastasks;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.boot.test.context.SpringBootTest;
+
+@SpringBootTest
+class TapasTasksApplicationTests {
+
+	@Test
+	void contextLoads() {
+	}
+
+}