Added code spec

.gitignore

+# Created by .ignore support plugin (hsz.mobi)
+### Gradle template
+.gradle
+/build/
+
+# Ignore Gradle GUI config
+gradle-app.setting
+
+# Avoid ignoring Gradle wrapper jar file (.jar files are usually ignored)
+!gradle-wrapper.jar
+
+# Cache of project
+.gradletasknamecache
+
+# User-specific stuff:
+**/.idea/
+
+# CMake
+cmake-build-debug/
+
+## File-based project format:
+*.iws
+*.iml
+
+## Plugin-specific files:
+
+# IntelliJ
+out/
+
+# mpeltonen/sbt-idea plugin
+.idea_modules/
+
+# JIRA plugin
+atlassian-ide-plugin.xml
+
+# Crashlytics plugin (for Android Studio and IntelliJ)
+com_crashlytics_export_strings.xml
+crashlytics.properties
+crashlytics-build.properties
+fabric.properties

build.gradle

+buildscript {
+    repositories {
+        mavenCentral()
+        jcenter()
+    }
+
+    dependencies {
+        classpath "com.github.ben-manes:gradle-versions-plugin:$gradle_versions_plugin_version"
+        classpath "org.junit.platform:junit-platform-gradle-plugin:$gradle_junit_plugin_version"
+    }
+}
+
+apply plugin: 'java'
+apply plugin: 'application'
+apply plugin: 'com.github.ben-manes.versions'
+apply plugin: 'org.junit.platform.gradle.plugin'
+
+repositories {
+    mavenLocal()
+    jcenter()
+    mavenCentral()
+}
+
+dependencies {
+    /* Commons Lang3 */
+    compile "org.apache.commons:commons-lang3:$commons_lang_version"
+
+    /* Retrofit */
+    compile "com.squareup.retrofit2:retrofit:$retrofit2_version"
+    compile "com.squareup.retrofit2:converter-gson:$retrofit2_version"
+    compile "com.squareup.retrofit2:adapter-java8:$retrofit2_version"
+
+    /* JUnit 5 */
+    testCompile("org.junit.jupiter:junit-jupiter-api:${junitJupiterVersion}")
+    testRuntime("org.junit.jupiter:junit-jupiter-engine:${junitJupiterVersion}")
+    testRuntime("org.junit.platform:junit-platform-launcher:${junitPlatformVersion}")
+    testRuntime("org.apache.logging.log4j:log4j-core:${log4jVersion}")
+    testRuntime("org.apache.logging.log4j:log4j-jul:${log4jVersion}")
+}
+
+mainClassName = 'de.fhro.inf.prg3.a12.App'
+
+sourceCompatibility = 1.8
+targetCompatibility = 1.8
\ No newline at end of file

gradle.properties

+gradle_versions_plugin_version=0.17.0
+gradle_junit_plugin_version=1.1.0-M1
+
+commons_lang_version=3.7
+retrofit2_version=2.3.0
+junitPlatformVersion = 1.1.0-M1
+junitJupiterVersion = 5.1.0-M1
+log4jVersion = 2.10.0
\ No newline at end of file

gradle/wrapper/gradle-wrapper.properties

+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-bin.zip

gradlew

+#!/usr/bin/env sh
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+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"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$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" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=$(save "$@")
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+# by default we should be in the correct project dir, but when run from Finder on Mac, the cwd is wrong
+if [ "$(uname)" = "Darwin" ] && [ "$HOME" = "$PWD" ]; then
+  cd "$(dirname "$0")"
+fi
+
+exec "$JAVACMD" "$@"

gradlew.bat

+@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 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=
+
+@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 init
+
+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 init
+
+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
+
+:init
+@rem Get command-line arguments, handling Windows variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+
+: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 %CMD_LINE_ARGS%
+
+: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

+/*
+ * This settings file was generated by the Gradle 'init' task.
+ *
+ * The settings file is used to specify which projects to include in your build.
+ * In a single project build this file can be empty or even removed.
+ *
+ * Detailed information about configuring a multi-project build in Gradle can be found
+ * in the user guide at https://docs.gradle.org/4.4/userguide/multi_project_builds.html
+ */
+
+/*
+// To declare projects as part of a multi-project build use the 'include' method
+include 'shared'
+include 'api'
+include 'services:webservice'
+*/
+
+rootProject.name = '12-functional-cli'

src/main/java/de/fhro/inf/prg3/a12/App.java

+package de.fhro.inf.prg3.a12;
+
+import de.fhro.inf.prg3.a12.icndb.JokeGenerator;
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+
+import java.util.Scanner;
+import java.util.stream.Stream;
+
+public abstract class App {
+
+    private static final Scanner inputScanner = new Scanner(System.in);
+    private static final JokeGenerator jokeGenerator = new JokeGenerator();
+
+    public static void main(String[] args) {
+        boolean shouldQuit = false;
+        int jokeCount;
+        int skipCount;
+        do {
+            jokeCount = readInt("How many jokes do you want?");
+            skipCount = readInt("How many jokes do you want to skip");
+
+            Stream<ResponseWrapper<JokeDto>> jokesSource;
+            switch (readJokeSource()) {
+                case Random:
+                    jokesSource = jokeGenerator.randomJokesStream();
+                    break;
+                default:
+                    jokesSource = jokeGenerator.jokesStream();
+            }
+
+            /* TODO consume the `jokesSource`
+             * filter it for non null objects
+             * use `skip` and `limit` to retrieve the required elements
+             * use `map` to unwrap the ResponseWrapper value
+             * and print the jokes to the STDOUT */
+
+            System.out.println("If you want to quit press [Q] otherwise press [C] to continue.");
+            String input = inputScanner.next();
+            if (input.equals("q") || input.equals("Q")) {
+                shouldQuit = true;
+            }
+        } while (!shouldQuit);
+        System.exit(0);
+    }
+
+    private static int readInt(String message) {
+        System.out.println(message);
+        do {
+            try {
+                int input = inputScanner.nextInt();
+                if (input >= 0) return input;
+            } catch (Exception e) {
+                System.out.println("Error while reading integer.");
+            }
+        } while (true);
+    }
+
+    private static JokeSource readJokeSource() {
+        System.out.println("Which joke source do you want to use?");
+        System.out.println("1) Random jokes");
+        System.out.println("2) Linear by id");
+
+        do {
+            try {
+                int selection = inputScanner.nextInt();
+                switch (selection) {
+                    case 1:
+                        return JokeSource.Random;
+                    default:
+                        return JokeSource.Linear;
+                }
+            } catch (Exception e) {
+                System.out.println("No valid selection");
+            }
+        } while (true);
+    }
+
+    enum JokeSource {
+        Random,
+        Linear
+    }
+}

src/main/java/de/fhro/inf/prg3/a12/icndb/ICNDBApi.java

+package de.fhro.inf.prg3.a12.icndb;
+
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import retrofit2.http.GET;
+import retrofit2.http.Path;
+import retrofit2.http.Query;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * @author Peter Kurfer
+ * Created on 12/28/17.
+ */
+public interface ICNDBApi {
+
+    @GET("/jokes/count")
+    CompletableFuture<ResponseWrapper<Integer>> getJokeCount();
+
+    @GET("/jokes/random")
+    CompletableFuture<ResponseWrapper<JokeDto>> getRandomJoke();
+
+    @GET("/jokes/random")
+    CompletableFuture<ResponseWrapper<JokeDto>> getRandomJoke(@Query("firstName") String firstName, @Query("lastName") String lastName);
+
+    @GET("/jokes/{id}")
+    CompletableFuture<ResponseWrapper<JokeDto>> getJoke(@Path("id") int number);
+
+}

src/main/java/de/fhro/inf/prg3/a12/icndb/ICNDBService.java

+package de.fhro.inf.prg3.a12.icndb;
+
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import retrofit2.Retrofit;
+import retrofit2.adapter.java8.Java8CallAdapterFactory;
+import retrofit2.converter.gson.GsonConverterFactory;
+
+import java.util.concurrent.CompletableFuture;
+
+/**
+ * @author Peter Kurfer
+ * Created on 12/28/17.
+ */
+public final class ICNDBService implements ICNDBApi {
+
+    private static final ICNDBService instance = new ICNDBService();
+
+    private final ICNDBApi icndbApi;
+
+    public static ICNDBService getInstance() {
+        return instance;
+    }
+
+    private ICNDBService() {
+        /* Initialize Retrofit */
+        Retrofit retrofit = new Retrofit.Builder()
+                .baseUrl("http://api.icndb.com")
+                .addConverterFactory(GsonConverterFactory.create())
+                .addCallAdapterFactory(Java8CallAdapterFactory.create())
+                .build();
+
+        icndbApi = retrofit.create(ICNDBApi.class);
+    }
+
+    @Override
+    public CompletableFuture<ResponseWrapper<Integer>> getJokeCount() {
+        return icndbApi.getJokeCount();
+    }
+
+    @Override
+    public CompletableFuture<ResponseWrapper<JokeDto>> getRandomJoke() {
+        return icndbApi.getRandomJoke();
+    }
+
+    @Override
+    public CompletableFuture<ResponseWrapper<JokeDto>> getRandomJoke(String firstName, String lastName) {
+        return icndbApi.getRandomJoke(firstName, lastName);
+    }
+
+    @Override
+    public CompletableFuture<ResponseWrapper<JokeDto>> getJoke(int number) {
+        return icndbApi.getJoke(number);
+    }
+}

src/main/java/de/fhro/inf/prg3/a12/icndb/JokeGenerator.java

+package de.fhro.inf.prg3.a12.icndb;
+
+import java.util.stream.Stream;
+
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import org.apache.commons.lang3.NotImplementedException;
+
+/**
+ * @author Peter Kurfer
+ */
+
+public final class JokeGenerator {
+
+    public Stream<ResponseWrapper<JokeDto>> randomJokesStream() {
+        /* TODO create new Stream of random jokes */
+        throw new NotImplementedException("Method `randomJokeStream()` is not implemented");
+    }
+
+    public Stream<ResponseWrapper<JokeDto>> jokesStream() {
+        /* TODO create a new Stream of all jokes */
+        throw new NotImplementedException("Method `jokesStream()` is not implemented");
+    }
+}

src/main/java/de/fhro/inf/prg3/a12/icndb/suppliers/AllJokesSupplier.java

+package de.fhro.inf.prg3.a12.icndb.suppliers;
+
+import java.util.function.Supplier;
+
+import de.fhro.inf.prg3.a12.icndb.ICNDBApi;
+import de.fhro.inf.prg3.a12.icndb.ICNDBService;
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import org.apache.commons.lang3.NotImplementedException;
+
+/**
+ * @author Peter Kurfer
+ */
+
+public final class AllJokesSupplier implements Supplier<ResponseWrapper<JokeDto>> {
+
+    private final ICNDBApi icndbApi;
+
+    public AllJokesSupplier() {
+        icndbApi = ICNDBService.getInstance();
+        /* TODO fetch the total count of jokes the API is aware of
+         * to determine when all jokes are iterated and the counters have to be reset */
+    }
+
+    @Override
+    public ResponseWrapper<JokeDto> get() {
+        /* TODO retrieve the next joke
+         * note that there might be IDs that are not present in the database
+         * you have to catch an exception and continue if no joke was retrieved to an ID
+         * if you retrieved all jokes (count how many jokes you successfully fetched from the API)
+         * reset the counters and continue at the beginning */
+        throw new NotImplementedException("Method `get()` is not implemented");
+    }
+
+}

src/main/java/de/fhro/inf/prg3/a12/icndb/suppliers/RandomJokeSupplier.java

+package de.fhro.inf.prg3.a12.icndb.suppliers;
+
+import java.util.function.Supplier;
+
+import de.fhro.inf.prg3.a12.icndb.ICNDBApi;
+import de.fhro.inf.prg3.a12.icndb.ICNDBService;
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import org.apache.commons.lang3.NotImplementedException;
+
+/**
+ * @author Peter Kurfer
+ */
+
+public final class RandomJokeSupplier implements Supplier<ResponseWrapper<JokeDto>> {
+
+    private final ICNDBApi icndbApi;
+
+    public RandomJokeSupplier() {
+        icndbApi = ICNDBService.getInstance();
+    }
+
+    @Override
+    public ResponseWrapper<JokeDto> get() {
+        /* TODO fetch a random joke synchronously
+         * if an exception occurs return null */
+        throw new NotImplementedException("Method `get()` is not implemented");
+    }
+}

src/main/java/de/fhro/inf/prg3/a12/model/JokeDto.java

+package de.fhro.inf.prg3.a12.model;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+import org.apache.commons.lang3.builder.ToStringBuilder;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * @author Peter Kurfer
+ * Created on 12/28/17.
+ */
+public class JokeDto {
+
+    private int id;
+    private String joke;
+    private List<String> categories;
+
+    public JokeDto() {
+        categories = new ArrayList<>();
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getJoke() {
+        return joke;
+    }
+
+    public void setJoke(String joke) {
+        this.joke = joke;
+    }
+
+    public List<String> getCategories() {
+        return categories;
+    }
+
+    public void setCategories(List<String> categories) {
+        if(categories == null) return;
+        this.categories = categories;
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+
+        if (!(o instanceof JokeDto)) return false;
+
+        JokeDto joke1 = (JokeDto) o;
+
+        return new EqualsBuilder()
+                .append(getId(), joke1.getId())
+                .append(getJoke(), joke1.getJoke())
+                .append(getCategories(), joke1.getCategories())
+                .isEquals();
+    }
+
+    @Override
+    public int hashCode() {
+        return new HashCodeBuilder(17, 37)
+                .append(getId())
+                .append(getJoke())
+                .append(getCategories())
+                .toHashCode();
+    }
+
+    @Override
+    public String toString() {
+        return new ToStringBuilder(this)
+                .append("id", id)
+                .append("joke", joke)
+                .append("categories", categories)
+                .toString();
+    }
+
+}

src/main/java/de/fhro/inf/prg3/a12/model/ResponseWrapper.java

+package de.fhro.inf.prg3.a12.model;
+
+import org.apache.commons.lang3.builder.EqualsBuilder;
+import org.apache.commons.lang3.builder.HashCodeBuilder;
+
+/**
+ * @author Peter Kurfer
+ * Created on 12/28/17.
+ */
+public class ResponseWrapper<T> {
+
+    private String type;
+
+    private T value;
+
+    public ResponseWrapper() {
+        type = "error";
+    }
+
+    public String getType() {
+        return type;
+    }
+
+    public void setType(String type) {
+        this.type = type;
+    }
+
+    public T getValue() {
+        return value;
+    }
+
+    public void setValue(T value) {
+        this.value = value;
+    }
+
+    public boolean isSuccessfull() {
+        return type != null && type.equals("success");
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+
+        if (!(o instanceof ResponseWrapper)) return false;
+
+        ResponseWrapper<?> that = (ResponseWrapper<?>) o;
+
+        return new EqualsBuilder()
+                .append(getType(), that.getType())
+                .append(getValue(), that.getValue())
+                .isEquals();
+    }
+
+    @Override
+    public int hashCode() {
+        return new HashCodeBuilder(17, 37)
+                .append(getType())
+                .append(getValue())
+                .toHashCode();
+    }
+
+}

src/test/java/de/fhro/inf/prg3/a12/icndb/ICNDBTests.java

+package de.fhro.inf.prg3.a12.icndb;
+
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import org.junit.jupiter.api.Test;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+import java.util.concurrent.CompletableFuture;
+import java.util.concurrent.ExecutionException;
+import java.util.logging.Logger;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+/**
+ * @author Peter Kurfer
+ */
+
+public class ICNDBTests {
+    private static final Logger logger = Logger.getLogger(ICNDBTests.class.getName());
+    private static final int REQUEST_COUNT = 100;
+
+    private ICNDBApi icndbApi;
+
+    public ICNDBTests() {
+        this.icndbApi = ICNDBService.getInstance();
+    }
+
+    @Test
+    void testCollision() throws ExecutionException, InterruptedException {
+        Set<Integer> jokeNumbers = new HashSet<>();
+        int requests = 0;
+        boolean collision = false;
+
+        while (requests++ < REQUEST_COUNT) {
+            CompletableFuture<ResponseWrapper<JokeDto>> jokeCall = icndbApi.getRandomJoke();
+            JokeDto joke = jokeCall.get().getValue();
+
+            if(jokeNumbers.contains(joke.getId())) {
+                logger.info(String.format("Collision at joke %s", joke.getId()));
+                collision = true;
+                break;
+            }
+
+            jokeNumbers.add(joke.getId());
+            logger.info(joke.toString());
+        }
+
+        assertTrue(collision, String.format("Completed %d requests without collision; consider increasing REQUEST_COUNT", requests));
+    }
+
+    @Test
+    void testGetRandomJokeWithChangedName() throws ExecutionException, InterruptedException {
+        JokeDto j = icndbApi.getRandomJoke("Bruce", "Wayne").get().getValue();
+        assertNotNull(j);
+        assertFalse(j.getJoke().contains("Chuck"));
+        assertFalse(j.getJoke().contains("Norris"));
+        logger.info(j.toString());
+    }
+
+    @Test
+    void testGetJokeById() throws ExecutionException, InterruptedException {
+
+        List<Integer> randomIds = new ArrayList<>(10);
+
+        for(int i = 0; i < 10; i++) {
+            randomIds.add(icndbApi.getRandomJoke().get().getValue().getId());
+        }
+
+        for(Integer id : randomIds) {
+            JokeDto j = icndbApi.getJoke(id).get().getValue();
+            assertNotNull(j);
+            assertTrue(randomIds.contains(j.getId()));
+            logger.info(j.toString());
+        }
+    }
+
+    @Test
+    void testGetJokeCount() throws ExecutionException, InterruptedException {
+        int jokeCount = icndbApi.getJokeCount().get().getValue();
+
+        assertNotEquals(0, jokeCount);
+    }
+
+}

src/test/java/de/fhro/inf/prg3/a12/icndb/JokesGeneratorTests.java

+package de.fhro.inf.prg3.a12.icndb;
+
+import de.fhro.inf.prg3.a12.model.JokeDto;
+import de.fhro.inf.prg3.a12.model.ResponseWrapper;
+import org.junit.jupiter.api.Test;
+
+import java.time.Duration;
+import java.util.Objects;
+import java.util.stream.Stream;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTimeout;
+
+/**
+ * @author Peter Kurfer
+ * Created on 12/28/17.
+ */
+class JokesGeneratorTests {
+
+    private JokeGenerator jokeGenerator = new JokeGenerator();
+
+    @Test
+    void testRandomStream() {
+        assertTimeout(Duration.ofSeconds(5L), () -> {
+            Stream<ResponseWrapper<JokeDto>> randomJokesStream = jokeGenerator.randomJokesStream();
+
+            randomJokesStream
+                    .filter(Objects::nonNull)
+                    .map(ResponseWrapper::getValue)
+                    .skip(3)
+                    .limit(5)
+                    .forEach(j -> {
+                        assertNotNull(j.getJoke());
+                        System.out.println(j.getJoke());
+                    });
+        });
+    }
+
+
+    @Test
+    void testJokesStream() {
+        assertTimeout(Duration.ofMinutes(1L), () -> {
+            jokeGenerator.jokesStream()
+                    .filter(Objects::nonNull)
+                    .map(ResponseWrapper::getValue)
+                    .skip(200L)
+                    .limit(400L)
+                    .forEach(j -> {
+                        assertNotNull(j.getJoke());
+                        System.out.println(j.getJoke());
+                    });
+        });
+    }
+
+}