├── .gitignore ├── build.gradle ├── gradle └── wrapper │ ├── gradle-wrapper.jar │ └── gradle-wrapper.properties ├── gradlew ├── gradlew.bat ├── readme.md ├── settings.gradle └── src ├── main ├── java │ └── library │ │ ├── LibraryApplication.java │ │ ├── UseCase.java │ │ ├── UseCaseLoggingAdvice.java │ │ ├── catalog │ │ ├── application │ │ │ ├── AddBookToCatalogUseCase.java │ │ │ ├── BookInformation.java │ │ │ ├── BookSearchService.java │ │ │ ├── DomainEventListener.java │ │ │ └── RegisterBookCopyUseCase.java │ │ ├── domain │ │ │ ├── BarCode.java │ │ │ ├── Book.java │ │ │ ├── BookId.java │ │ │ ├── BookRepository.java │ │ │ ├── Copy.java │ │ │ ├── CopyId.java │ │ │ ├── CopyRepository.java │ │ │ └── Isbn.java │ │ └── infrastructure │ │ │ ├── OpenLibraryBookSearchService.java │ │ │ └── OpenLibraryIsbnSearchResult.java │ │ └── lending │ │ ├── application │ │ ├── RentBookUseCase.java │ │ └── ReturnBookUseCase.java │ │ └── domain │ │ ├── CopyId.java │ │ ├── Loan.java │ │ ├── LoanClosed.java │ │ ├── LoanCreated.java │ │ ├── LoanId.java │ │ ├── LoanRepository.java │ │ └── UserId.java └── resources │ └── application.properties └── test └── java └── library └── LibraryApplicationTests.java /.gitignore: -------------------------------------------------------------------------------- 1 | HELP.md 2 | .gradle 3 | build/ 4 | !gradle/wrapper/gradle-wrapper.jar 5 | !**/src/main/**/build/ 6 | !**/src/test/**/build/ 7 | 8 | ### STS ### 9 | .apt_generated 10 | .classpath 11 | .factorypath 12 | .project 13 | .settings 14 | .springBeans 15 | .sts4-cache 16 | bin/ 17 | !**/src/main/**/bin/ 18 | !**/src/test/**/bin/ 19 | 20 | ### IntelliJ IDEA ### 21 | .idea 22 | *.iws 23 | *.iml 24 | *.ipr 25 | out/ 26 | !**/src/main/**/out/ 27 | !**/src/test/**/out/ 28 | 29 | ### NetBeans ### 30 | /nbproject/private/ 31 | /nbbuild/ 32 | /dist/ 33 | /nbdist/ 34 | /.nb-gradle/ 35 | 36 | ### VS Code ### 37 | .vscode/ 38 | -------------------------------------------------------------------------------- /build.gradle: -------------------------------------------------------------------------------- 1 | plugins { 2 | id 'java' 3 | id 'org.springframework.boot' version '3.3.0' 4 | id 'io.spring.dependency-management' version '1.1.5' 5 | } 6 | 7 | group = 'library' 8 | version = '0.0.1-SNAPSHOT' 9 | 10 | java { 11 | sourceCompatibility = '21' 12 | } 13 | 14 | repositories { 15 | mavenCentral() 16 | maven { url 'https://repo.spring.io/milestone' } 17 | } 18 | 19 | ext { 20 | set('springModulithVersion', "1.2.0-RC1") 21 | } 22 | 23 | dependencies { 24 | implementation 'org.springframework.boot:spring-boot-starter-web' 25 | implementation 'org.springframework.boot:spring-boot-starter-validation' 26 | implementation 'org.springframework.boot:spring-boot-starter-data-jpa' 27 | implementation 'org.springframework.modulith:spring-modulith-starter-core' 28 | implementation 'org.springframework.modulith:spring-modulith-starter-jpa' 29 | runtimeOnly 'org.postgresql:postgresql' 30 | 31 | implementation 'commons-validator:commons-validator:1.8.0' 32 | 33 | implementation 'org.javamoney:moneta:1.4.4' 34 | implementation 'io.hypersistence:hypersistence-utils-hibernate-63:3.7.5' 35 | 36 | testImplementation 'org.springframework.boot:spring-boot-starter-test' 37 | testImplementation 'org.springframework.boot:spring-boot-testcontainers' 38 | testImplementation 'org.springframework.modulith:spring-modulith-starter-test' 39 | testImplementation 'org.testcontainers:junit-jupiter' 40 | testImplementation 'org.testcontainers:postgresql' 41 | testRuntimeOnly 'org.junit.platform:junit-platform-launcher' 42 | } 43 | 44 | dependencyManagement { 45 | imports { 46 | mavenBom "org.springframework.modulith:spring-modulith-bom:${springModulithVersion}" 47 | } 48 | } 49 | 50 | tasks.named('test') { 51 | useJUnitPlatform() 52 | } 53 | -------------------------------------------------------------------------------- /gradle/wrapper/gradle-wrapper.jar: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/maciejwalkowiak/implementing-ddd-with-spring-talk/d5123ba9ec9554bf06343d6b84876fa963626eaf/gradle/wrapper/gradle-wrapper.jar -------------------------------------------------------------------------------- /gradle/wrapper/gradle-wrapper.properties: -------------------------------------------------------------------------------- 1 | distributionBase=GRADLE_USER_HOME 2 | distributionPath=wrapper/dists 3 | distributionUrl=https\://services.gradle.org/distributions/gradle-8.7-bin.zip 4 | networkTimeout=10000 5 | validateDistributionUrl=true 6 | zipStoreBase=GRADLE_USER_HOME 7 | zipStorePath=wrapper/dists 8 | -------------------------------------------------------------------------------- /gradlew: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | # 4 | # Copyright © 2015-2021 the original authors. 5 | # 6 | # Licensed under the Apache License, Version 2.0 (the "License"); 7 | # you may not use this file except in compliance with the License. 8 | # You may obtain a copy of the License at 9 | # 10 | # https://www.apache.org/licenses/LICENSE-2.0 11 | # 12 | # Unless required by applicable law or agreed to in writing, software 13 | # distributed under the License is distributed on an "AS IS" BASIS, 14 | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 15 | # See the License for the specific language governing permissions and 16 | # limitations under the License. 17 | # 18 | 19 | ############################################################################## 20 | # 21 | # Gradle start up script for POSIX generated by Gradle. 22 | # 23 | # Important for running: 24 | # 25 | # (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is 26 | # noncompliant, but you have some other compliant shell such as ksh or 27 | # bash, then to run this script, type that shell name before the whole 28 | # command line, like: 29 | # 30 | # ksh Gradle 31 | # 32 | # Busybox and similar reduced shells will NOT work, because this script 33 | # requires all of these POSIX shell features: 34 | # * functions; 35 | # * expansions «$var», «${var}», «${var:-default}», «${var+SET}», 36 | # «${var#prefix}», «${var%suffix}», and «$( cmd )»; 37 | # * compound commands having a testable exit status, especially «case»; 38 | # * various built-in commands including «command», «set», and «ulimit». 39 | # 40 | # Important for patching: 41 | # 42 | # (2) This script targets any POSIX shell, so it avoids extensions provided 43 | # by Bash, Ksh, etc; in particular arrays are avoided. 44 | # 45 | # The "traditional" practice of packing multiple parameters into a 46 | # space-separated string is a well documented source of bugs and security 47 | # problems, so this is (mostly) avoided, by progressively accumulating 48 | # options in "$@", and eventually passing that to Java. 49 | # 50 | # Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS, 51 | # and GRADLE_OPTS) rely on word-splitting, this is performed explicitly; 52 | # see the in-line comments for details. 53 | # 54 | # There are tweaks for specific operating systems such as AIX, CygWin, 55 | # Darwin, MinGW, and NonStop. 56 | # 57 | # (3) This script is generated from the Groovy template 58 | # https://github.com/gradle/gradle/blob/HEAD/subprojects/plugins/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt 59 | # within the Gradle project. 60 | # 61 | # You can find Gradle at https://github.com/gradle/gradle/. 62 | # 63 | ############################################################################## 64 | 65 | # Attempt to set APP_HOME 66 | 67 | # Resolve links: $0 may be a link 68 | app_path=$0 69 | 70 | # Need this for daisy-chained symlinks. 71 | while 72 | APP_HOME=${app_path%"${app_path##*/}"} # leaves a trailing /; empty if no leading path 73 | [ -h "$app_path" ] 74 | do 75 | ls=$( ls -ld "$app_path" ) 76 | link=${ls#*' -> '} 77 | case $link in #( 78 | /*) app_path=$link ;; #( 79 | *) app_path=$APP_HOME$link ;; 80 | esac 81 | done 82 | 83 | # This is normally unused 84 | # shellcheck disable=SC2034 85 | APP_BASE_NAME=${0##*/} 86 | # Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036) 87 | APP_HOME=$( cd "${APP_HOME:-./}" > /dev/null && pwd -P ) || exit 88 | 89 | # Use the maximum available, or set MAX_FD != -1 to use that value. 90 | MAX_FD=maximum 91 | 92 | warn () { 93 | echo "$*" 94 | } >&2 95 | 96 | die () { 97 | echo 98 | echo "$*" 99 | echo 100 | exit 1 101 | } >&2 102 | 103 | # OS specific support (must be 'true' or 'false'). 104 | cygwin=false 105 | msys=false 106 | darwin=false 107 | nonstop=false 108 | case "$( uname )" in #( 109 | CYGWIN* ) cygwin=true ;; #( 110 | Darwin* ) darwin=true ;; #( 111 | MSYS* | MINGW* ) msys=true ;; #( 112 | NONSTOP* ) nonstop=true ;; 113 | esac 114 | 115 | CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar 116 | 117 | 118 | # Determine the Java command to use to start the JVM. 119 | if [ -n "$JAVA_HOME" ] ; then 120 | if [ -x "$JAVA_HOME/jre/sh/java" ] ; then 121 | # IBM's JDK on AIX uses strange locations for the executables 122 | JAVACMD=$JAVA_HOME/jre/sh/java 123 | else 124 | JAVACMD=$JAVA_HOME/bin/java 125 | fi 126 | if [ ! -x "$JAVACMD" ] ; then 127 | die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME 128 | 129 | Please set the JAVA_HOME variable in your environment to match the 130 | location of your Java installation." 131 | fi 132 | else 133 | JAVACMD=java 134 | if ! command -v java >/dev/null 2>&1 135 | then 136 | die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 137 | 138 | Please set the JAVA_HOME variable in your environment to match the 139 | location of your Java installation." 140 | fi 141 | fi 142 | 143 | # Increase the maximum file descriptors if we can. 144 | if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then 145 | case $MAX_FD in #( 146 | max*) 147 | # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked. 148 | # shellcheck disable=SC2039,SC3045 149 | MAX_FD=$( ulimit -H -n ) || 150 | warn "Could not query maximum file descriptor limit" 151 | esac 152 | case $MAX_FD in #( 153 | '' | soft) :;; #( 154 | *) 155 | # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked. 156 | # shellcheck disable=SC2039,SC3045 157 | ulimit -n "$MAX_FD" || 158 | warn "Could not set maximum file descriptor limit to $MAX_FD" 159 | esac 160 | fi 161 | 162 | # Collect all arguments for the java command, stacking in reverse order: 163 | # * args from the command line 164 | # * the main class name 165 | # * -classpath 166 | # * -D...appname settings 167 | # * --module-path (only if needed) 168 | # * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables. 169 | 170 | # For Cygwin or MSYS, switch paths to Windows format before running java 171 | if "$cygwin" || "$msys" ; then 172 | APP_HOME=$( cygpath --path --mixed "$APP_HOME" ) 173 | CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" ) 174 | 175 | JAVACMD=$( cygpath --unix "$JAVACMD" ) 176 | 177 | # Now convert the arguments - kludge to limit ourselves to /bin/sh 178 | for arg do 179 | if 180 | case $arg in #( 181 | -*) false ;; # don't mess with options #( 182 | /?*) t=${arg#/} t=/${t%%/*} # looks like a POSIX filepath 183 | [ -e "$t" ] ;; #( 184 | *) false ;; 185 | esac 186 | then 187 | arg=$( cygpath --path --ignore --mixed "$arg" ) 188 | fi 189 | # Roll the args list around exactly as many times as the number of 190 | # args, so each arg winds up back in the position where it started, but 191 | # possibly modified. 192 | # 193 | # NB: a `for` loop captures its iteration list before it begins, so 194 | # changing the positional parameters here affects neither the number of 195 | # iterations, nor the values presented in `arg`. 196 | shift # remove old arg 197 | set -- "$@" "$arg" # push replacement arg 198 | done 199 | fi 200 | 201 | 202 | # Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. 203 | DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"' 204 | 205 | # Collect all arguments for the java command: 206 | # * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments, 207 | # and any embedded shellness will be escaped. 208 | # * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be 209 | # treated as '${Hostname}' itself on the command line. 210 | 211 | set -- \ 212 | "-Dorg.gradle.appname=$APP_BASE_NAME" \ 213 | -classpath "$CLASSPATH" \ 214 | org.gradle.wrapper.GradleWrapperMain \ 215 | "$@" 216 | 217 | # Stop when "xargs" is not available. 218 | if ! command -v xargs >/dev/null 2>&1 219 | then 220 | die "xargs is not available" 221 | fi 222 | 223 | # Use "xargs" to parse quoted args. 224 | # 225 | # With -n1 it outputs one arg per line, with the quotes and backslashes removed. 226 | # 227 | # In Bash we could simply go: 228 | # 229 | # readarray ARGS < <( xargs -n1 <<<"$var" ) && 230 | # set -- "${ARGS[@]}" "$@" 231 | # 232 | # but POSIX shell has neither arrays nor command substitution, so instead we 233 | # post-process each arg (as a line of input to sed) to backslash-escape any 234 | # character that might be a shell metacharacter, then use eval to reverse 235 | # that process (while maintaining the separation between arguments), and wrap 236 | # the whole thing up as a single "set" statement. 237 | # 238 | # This will of course break if any of these variables contains a newline or 239 | # an unmatched quote. 240 | # 241 | 242 | eval "set -- $( 243 | printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" | 244 | xargs -n1 | 245 | sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' | 246 | tr '\n' ' ' 247 | )" '"$@"' 248 | 249 | exec "$JAVACMD" "$@" 250 | -------------------------------------------------------------------------------- /gradlew.bat: -------------------------------------------------------------------------------- 1 | @rem 2 | @rem Copyright 2015 the original author or authors. 3 | @rem 4 | @rem Licensed under the Apache License, Version 2.0 (the "License"); 5 | @rem you may not use this file except in compliance with the License. 6 | @rem You may obtain a copy of the License at 7 | @rem 8 | @rem https://www.apache.org/licenses/LICENSE-2.0 9 | @rem 10 | @rem Unless required by applicable law or agreed to in writing, software 11 | @rem distributed under the License is distributed on an "AS IS" BASIS, 12 | @rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 | @rem See the License for the specific language governing permissions and 14 | @rem limitations under the License. 15 | @rem 16 | 17 | @if "%DEBUG%"=="" @echo off 18 | @rem ########################################################################## 19 | @rem 20 | @rem Gradle startup script for Windows 21 | @rem 22 | @rem ########################################################################## 23 | 24 | @rem Set local scope for the variables with windows NT shell 25 | if "%OS%"=="Windows_NT" setlocal 26 | 27 | set DIRNAME=%~dp0 28 | if "%DIRNAME%"=="" set DIRNAME=. 29 | @rem This is normally unused 30 | set APP_BASE_NAME=%~n0 31 | set APP_HOME=%DIRNAME% 32 | 33 | @rem Resolve any "." and ".." in APP_HOME to make it shorter. 34 | for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi 35 | 36 | @rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script. 37 | set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m" 38 | 39 | @rem Find java.exe 40 | if defined JAVA_HOME goto findJavaFromJavaHome 41 | 42 | set JAVA_EXE=java.exe 43 | %JAVA_EXE% -version >NUL 2>&1 44 | if %ERRORLEVEL% equ 0 goto execute 45 | 46 | echo. 1>&2 47 | echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2 48 | echo. 1>&2 49 | echo Please set the JAVA_HOME variable in your environment to match the 1>&2 50 | echo location of your Java installation. 1>&2 51 | 52 | goto fail 53 | 54 | :findJavaFromJavaHome 55 | set JAVA_HOME=%JAVA_HOME:"=% 56 | set JAVA_EXE=%JAVA_HOME%/bin/java.exe 57 | 58 | if exist "%JAVA_EXE%" goto execute 59 | 60 | echo. 1>&2 61 | echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2 62 | echo. 1>&2 63 | echo Please set the JAVA_HOME variable in your environment to match the 1>&2 64 | echo location of your Java installation. 1>&2 65 | 66 | goto fail 67 | 68 | :execute 69 | @rem Setup the command line 70 | 71 | set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar 72 | 73 | 74 | @rem Execute Gradle 75 | "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %* 76 | 77 | :end 78 | @rem End local scope for the variables with windows NT shell 79 | if %ERRORLEVEL% equ 0 goto mainEnd 80 | 81 | :fail 82 | rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of 83 | rem the _cmd.exe /c_ return code! 84 | set EXIT_CODE=%ERRORLEVEL% 85 | if %EXIT_CODE% equ 0 set EXIT_CODE=1 86 | if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE% 87 | exit /b %EXIT_CODE% 88 | 89 | :mainEnd 90 | if "%OS%"=="Windows_NT" endlocal 91 | 92 | :omega 93 | -------------------------------------------------------------------------------- /readme.md: -------------------------------------------------------------------------------- 1 | # Implementing Domain Driven Design with Spring 2 | 3 | This repository contains code for the talk I gave at [Spring IO 2024](https://2024.springio.net/sessions/implementing-domain-driven-design-with-spring/): "Implementing Domain Driven Design with Spring" 4 | 5 | - [YouTube](https://www.youtube.com/watch?v=VGhg6Tfxb60) 6 | - [Slides](https://speakerdeck.com/maciejwalkowiak/implementing-domain-driven-desing-with-spring) 7 | -------------------------------------------------------------------------------- /settings.gradle: -------------------------------------------------------------------------------- 1 | rootProject.name = 'library' 2 | -------------------------------------------------------------------------------- /src/main/java/library/LibraryApplication.java: -------------------------------------------------------------------------------- 1 | package library; 2 | 3 | import org.springframework.boot.SpringApplication; 4 | import org.springframework.boot.autoconfigure.SpringBootApplication; 5 | 6 | @SpringBootApplication 7 | public class LibraryApplication { 8 | 9 | public static void main(String[] args) { 10 | SpringApplication.run(LibraryApplication.class, args); 11 | } 12 | 13 | } 14 | -------------------------------------------------------------------------------- /src/main/java/library/UseCase.java: -------------------------------------------------------------------------------- 1 | package library; 2 | 3 | import org.springframework.stereotype.Service; 4 | import org.springframework.validation.annotation.Validated; 5 | 6 | import java.lang.annotation.Documented; 7 | import java.lang.annotation.ElementType; 8 | import java.lang.annotation.Retention; 9 | import java.lang.annotation.RetentionPolicy; 10 | import java.lang.annotation.Target; 11 | 12 | @Documented 13 | @Target(ElementType.TYPE) 14 | @Retention(RetentionPolicy.RUNTIME) 15 | @Service 16 | @Validated 17 | public @interface UseCase { 18 | } 19 | -------------------------------------------------------------------------------- /src/main/java/library/UseCaseLoggingAdvice.java: -------------------------------------------------------------------------------- 1 | package library; 2 | 3 | import org.aspectj.lang.ProceedingJoinPoint; 4 | import org.aspectj.lang.annotation.Around; 5 | import org.aspectj.lang.annotation.Aspect; 6 | import org.aspectj.lang.annotation.Pointcut; 7 | import org.slf4j.Logger; 8 | import org.slf4j.LoggerFactory; 9 | import org.springframework.core.annotation.Order; 10 | import org.springframework.stereotype.Component; 11 | import org.springframework.util.StopWatch; 12 | 13 | import java.util.Arrays; 14 | 15 | @Component 16 | @Aspect 17 | @Order(1) 18 | public class UseCaseLoggingAdvice { 19 | private static final Logger LOGGER = LoggerFactory.getLogger(library.UseCaseLoggingAdvice.class); 20 | 21 | @Pointcut("within(@library.UseCase *)") 22 | public void useCase() { 23 | } 24 | 25 | @Pointcut("execution(public * *(..))") 26 | public void publicMethod() { 27 | } 28 | 29 | @Pointcut("publicMethod() && useCase()") 30 | public void publicMethodInsideAUseCase() { 31 | } 32 | 33 | @Around("publicMethodInsideAUseCase()") 34 | public Object aroundServiceMethodAdvice(final ProceedingJoinPoint pjp) throws Throwable { 35 | StopWatch stopWatch = new StopWatch(); 36 | try { 37 | LOGGER.info("Executing use case: {}#{} with parameters: {}", pjp.getTarget().getClass(), pjp.getSignature().getName(), Arrays.toString(pjp.getArgs())); 38 | stopWatch.start(); 39 | return pjp.proceed(); 40 | } finally { 41 | stopWatch.stop(); 42 | LOGGER.info("Finished executing use case {}#{} in {}ms", pjp.getTarget().getClass(), pjp.getSignature().getName(), stopWatch.getTotalTimeMillis()); 43 | } 44 | } 45 | } 46 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/application/AddBookToCatalogUseCase.java: -------------------------------------------------------------------------------- 1 | package library.catalog.application; 2 | 3 | import library.UseCase; 4 | import library.catalog.domain.Book; 5 | import library.catalog.domain.BookRepository; 6 | import library.catalog.domain.Isbn; 7 | 8 | @UseCase 9 | public class AddBookToCatalogUseCase { 10 | private final BookSearchService bookSearchService; 11 | private final BookRepository bookRepository; 12 | 13 | public AddBookToCatalogUseCase(BookSearchService bookSearchService, BookRepository bookRepository) { 14 | this.bookSearchService = bookSearchService; 15 | this.bookRepository = bookRepository; 16 | } 17 | 18 | public void execute(Isbn isbn) { 19 | BookInformation result = bookSearchService.search(isbn); 20 | Book book = new Book(result.title(), isbn); 21 | bookRepository.save(book); 22 | } 23 | } 24 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/application/BookInformation.java: -------------------------------------------------------------------------------- 1 | package library.catalog.application; 2 | 3 | public record BookInformation(String title) { 4 | } 5 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/application/BookSearchService.java: -------------------------------------------------------------------------------- 1 | package library.catalog.application; 2 | 3 | import library.catalog.domain.Isbn; 4 | 5 | public interface BookSearchService { 6 | BookInformation search(Isbn isbn); 7 | } 8 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/application/DomainEventListener.java: -------------------------------------------------------------------------------- 1 | package library.catalog.application; 2 | 3 | import library.catalog.domain.Copy; 4 | import library.catalog.domain.CopyId; 5 | import library.catalog.domain.CopyRepository; 6 | import library.lending.domain.LoanClosed; 7 | import library.lending.domain.LoanCreated; 8 | import org.springframework.modulith.events.ApplicationModuleListener; 9 | import org.springframework.stereotype.Component; 10 | 11 | @Component 12 | public class DomainEventListener { 13 | 14 | private final CopyRepository copyRepository; 15 | 16 | public DomainEventListener(CopyRepository copyRepository) { 17 | this.copyRepository = copyRepository; 18 | } 19 | 20 | @ApplicationModuleListener 21 | public void handle(LoanCreated event) { 22 | Copy copy = copyRepository.findById(new CopyId(event.copyId().id())).orElseThrow(); 23 | copy.makeUnavailable(); 24 | copyRepository.save(copy); 25 | } 26 | 27 | @ApplicationModuleListener 28 | public void handle(LoanClosed event) { 29 | Copy copy = copyRepository.findById(new CopyId(event.copyId().id())).orElseThrow(); 30 | copy.makeAvailable(); 31 | copyRepository.save(copy); 32 | } 33 | } 34 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/application/RegisterBookCopyUseCase.java: -------------------------------------------------------------------------------- 1 | package library.catalog.application; 2 | 3 | import jakarta.validation.constraints.NotNull; 4 | import library.UseCase; 5 | import library.catalog.domain.BarCode; 6 | import library.catalog.domain.BookId; 7 | import library.catalog.domain.Copy; 8 | import library.catalog.domain.CopyRepository; 9 | 10 | @UseCase 11 | public class RegisterBookCopyUseCase { 12 | private final CopyRepository copyRepository; 13 | 14 | public RegisterBookCopyUseCase(CopyRepository copyRepository) { 15 | this.copyRepository = copyRepository; 16 | } 17 | 18 | public void execute(@NotNull BookId bookId, @NotNull BarCode barCode) { 19 | copyRepository.save(new Copy(bookId, barCode)); 20 | } 21 | } 22 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/BarCode.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | public record BarCode(String code) { 6 | public BarCode { 7 | Assert.notNull(code, "Bar code must not be null"); 8 | } 9 | } 10 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/Book.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import jakarta.persistence.AttributeOverride; 4 | import jakarta.persistence.AttributeOverrides; 5 | import jakarta.persistence.Column; 6 | import jakarta.persistence.Embedded; 7 | import jakarta.persistence.EmbeddedId; 8 | import jakarta.persistence.Entity; 9 | import org.springframework.util.Assert; 10 | 11 | import java.util.Objects; 12 | 13 | @Entity 14 | public class Book { 15 | @EmbeddedId 16 | private BookId id; 17 | private String title; 18 | @Embedded 19 | @AttributeOverride(name = "value", column = @Column(name = "isbn")) 20 | private Isbn isbn; 21 | 22 | Book() { 23 | } 24 | 25 | public Book(String title, Isbn isbn) { 26 | Assert.notNull(title, "title must not be null"); 27 | Assert.notNull(isbn, "isbn must not be null"); 28 | this.id = new BookId(); 29 | this.title = title; 30 | this.isbn = isbn; 31 | } 32 | 33 | public BookId getId() { 34 | return id; 35 | } 36 | 37 | public String getTitle() { 38 | return title; 39 | } 40 | 41 | public Isbn getIsbn() { 42 | return isbn; 43 | } 44 | 45 | @Override 46 | public boolean equals(Object o) { 47 | if (this == o) return true; 48 | if (o == null || getClass() != o.getClass()) return false; 49 | Book book = (Book) o; 50 | return Objects.equals(id, book.id); 51 | } 52 | 53 | @Override 54 | public int hashCode() { 55 | return Objects.hashCode(id); 56 | } 57 | } 58 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/BookId.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | import java.util.UUID; 6 | 7 | public record BookId(UUID id) { 8 | 9 | public BookId { 10 | Assert.notNull(id, "id must not be null"); 11 | } 12 | 13 | public BookId() { 14 | this(UUID.randomUUID()); 15 | } 16 | } 17 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/BookRepository.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.springframework.data.repository.CrudRepository; 4 | 5 | public interface BookRepository extends CrudRepository { 6 | } 7 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/Copy.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import jakarta.persistence.AttributeOverride; 4 | import jakarta.persistence.Column; 5 | import jakarta.persistence.Embedded; 6 | import jakarta.persistence.EmbeddedId; 7 | import jakarta.persistence.Entity; 8 | import org.springframework.util.Assert; 9 | 10 | @Entity 11 | public class Copy { 12 | @EmbeddedId 13 | private CopyId id; 14 | @Embedded 15 | @AttributeOverride(name = "id", column = @Column(name = "book_id")) 16 | private BookId bookId; 17 | @Embedded 18 | private BarCode barCode; 19 | private boolean available; 20 | 21 | Copy() { 22 | } 23 | 24 | public Copy(BookId bookId, BarCode barCode) { 25 | Assert.notNull(bookId, "bookId must not be null"); 26 | Assert.notNull(barCode, "barCode must not be null"); 27 | this.id = new CopyId(); 28 | this.bookId = bookId; 29 | this.barCode = barCode; 30 | this.available = true; 31 | } 32 | 33 | public void makeUnavailable() { 34 | this.available = false; 35 | } 36 | 37 | public void makeAvailable() { 38 | this.available = true; 39 | } 40 | } 41 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/CopyId.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | import java.util.UUID; 6 | 7 | public record CopyId(UUID id) { 8 | 9 | public CopyId { 10 | Assert.notNull(id, "id must not be null"); 11 | } 12 | 13 | public CopyId() { 14 | this(UUID.randomUUID()); 15 | } 16 | } 17 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/CopyRepository.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.springframework.data.repository.CrudRepository; 4 | 5 | public interface CopyRepository extends CrudRepository { 6 | } 7 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/domain/Isbn.java: -------------------------------------------------------------------------------- 1 | package library.catalog.domain; 2 | 3 | import org.apache.commons.validator.routines.ISBNValidator; 4 | 5 | public record Isbn(String value) { 6 | private static final ISBNValidator VALIDATOR = new ISBNValidator(); 7 | 8 | public Isbn { 9 | if (!VALIDATOR.isValid(value)) { 10 | throw new IllegalArgumentException("invalid isbn: " + value); 11 | } 12 | } 13 | } 14 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/infrastructure/OpenLibraryBookSearchService.java: -------------------------------------------------------------------------------- 1 | package library.catalog.infrastructure; 2 | 3 | import library.catalog.application.BookInformation; 4 | import library.catalog.application.BookSearchService; 5 | import library.catalog.domain.Isbn; 6 | import org.springframework.stereotype.Service; 7 | import org.springframework.web.client.RestClient; 8 | 9 | @Service 10 | class OpenLibraryBookSearchService implements BookSearchService { 11 | private final RestClient restClient; 12 | 13 | public OpenLibraryBookSearchService(RestClient.Builder builder) { 14 | this.restClient = builder 15 | .baseUrl("https://openlibrary.org/") 16 | .build(); 17 | } 18 | 19 | public BookInformation search(Isbn isbn) { 20 | OpenLibraryIsbnSearchResult result = restClient.get().uri("isbn/{isbn}.json", isbn.value()) 21 | .retrieve() 22 | .body(OpenLibraryIsbnSearchResult.class); 23 | return new BookInformation(result.title()); 24 | } 25 | } 26 | -------------------------------------------------------------------------------- /src/main/java/library/catalog/infrastructure/OpenLibraryIsbnSearchResult.java: -------------------------------------------------------------------------------- 1 | package library.catalog.infrastructure; 2 | 3 | import java.util.List; 4 | 5 | record OpenLibraryIsbnSearchResult(List publishers, 6 | String title, 7 | List isbn_13, 8 | int revisions) { 9 | } 10 | -------------------------------------------------------------------------------- /src/main/java/library/lending/application/RentBookUseCase.java: -------------------------------------------------------------------------------- 1 | package library.lending.application; 2 | 3 | import library.UseCase; 4 | import library.lending.domain.CopyId; 5 | import library.lending.domain.Loan; 6 | import library.lending.domain.LoanRepository; 7 | import library.lending.domain.UserId; 8 | 9 | @UseCase 10 | public class RentBookUseCase { 11 | private final LoanRepository loanRepository; 12 | 13 | public RentBookUseCase(LoanRepository loanRepository) { 14 | this.loanRepository = loanRepository; 15 | } 16 | 17 | public void execute(CopyId copyId, UserId userId) { 18 | // TODO: ensure rented copy is not rented again 19 | loanRepository.save(new Loan(copyId, userId, loanRepository)); 20 | } 21 | } 22 | -------------------------------------------------------------------------------- /src/main/java/library/lending/application/ReturnBookUseCase.java: -------------------------------------------------------------------------------- 1 | package library.lending.application; 2 | 3 | import library.UseCase; 4 | import library.lending.domain.Loan; 5 | import library.lending.domain.LoanId; 6 | import library.lending.domain.LoanRepository; 7 | 8 | @UseCase 9 | public class ReturnBookUseCase { 10 | 11 | 12 | private final LoanRepository loanRepository; 13 | 14 | public ReturnBookUseCase(LoanRepository loanRepository) { 15 | this.loanRepository = loanRepository; 16 | } 17 | 18 | public void execute(LoanId loanId) { 19 | Loan loan = loanRepository.findByIdOrThrow(loanId); 20 | loan.returned(); 21 | } 22 | } 23 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/CopyId.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | import java.util.UUID; 6 | 7 | public record CopyId(UUID id) { 8 | 9 | public CopyId { 10 | Assert.notNull(id, "id must not be null"); 11 | } 12 | 13 | public CopyId() { 14 | this(UUID.randomUUID()); 15 | } 16 | } 17 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/Loan.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | import jakarta.persistence.AttributeOverride; 4 | import jakarta.persistence.Column; 5 | import jakarta.persistence.Embedded; 6 | import jakarta.persistence.EmbeddedId; 7 | import jakarta.persistence.Entity; 8 | import jakarta.persistence.Version; 9 | import org.springframework.data.domain.AbstractAggregateRoot; 10 | import org.springframework.util.Assert; 11 | 12 | import java.time.LocalDate; 13 | import java.time.LocalDateTime; 14 | 15 | @Entity 16 | public class Loan extends AbstractAggregateRoot { 17 | @EmbeddedId 18 | private LoanId loanId; 19 | @Embedded 20 | @AttributeOverride(name = "id", column = @Column(name = "copy_id")) 21 | private CopyId copyId; 22 | @Embedded 23 | @AttributeOverride(name = "id", column = @Column(name = "user_id")) 24 | private UserId userId; 25 | private LocalDateTime createdAt; 26 | private LocalDate expectedReturnDate; 27 | private LocalDateTime returnedAt; 28 | 29 | @Version 30 | private Long version; 31 | 32 | Loan() { 33 | } 34 | 35 | public Loan(CopyId copyId, UserId userId, LoanRepository loanRepository) { 36 | Assert.notNull(copyId, "copyId must not be null"); 37 | Assert.notNull(userId, "userId must not be null"); 38 | Assert.isTrue(loanRepository.isAvailable(copyId), "copy with id = " + copyId + " is not available"); 39 | this.loanId = new LoanId(); 40 | this.copyId = copyId; 41 | this.userId = userId; 42 | this.createdAt = LocalDateTime.now(); 43 | this.expectedReturnDate = LocalDate.now().plusDays(30); 44 | this.registerEvent(new LoanCreated(this.copyId)); 45 | } 46 | 47 | public void returned() { 48 | this.returnedAt = LocalDateTime.now(); 49 | if (this.returnedAt.isAfter(expectedReturnDate.atStartOfDay())) { 50 | // calculate fee 51 | } 52 | this.registerEvent(new LoanClosed(this.copyId)); 53 | } 54 | } 55 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/LoanClosed.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | public record LoanClosed(CopyId copyId) { 4 | } 5 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/LoanCreated.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | public record LoanCreated(CopyId copyId) { 4 | } 5 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/LoanId.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | import java.util.UUID; 6 | 7 | public record LoanId(UUID id) { 8 | 9 | public LoanId { 10 | Assert.notNull(id, "id must not be null"); 11 | } 12 | 13 | public LoanId() { 14 | this(UUID.randomUUID()); 15 | } 16 | } 17 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/LoanRepository.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | import org.springframework.data.jpa.repository.Query; 4 | import org.springframework.data.repository.CrudRepository; 5 | 6 | public interface LoanRepository extends CrudRepository { 7 | @Query("select count(*) = 0 from Loan where copyId = :id and returnedAt is null") 8 | boolean isAvailable(CopyId id); 9 | 10 | default Loan findByIdOrThrow(LoanId loanId) { 11 | return findById(loanId).orElseThrow(); 12 | } 13 | } 14 | -------------------------------------------------------------------------------- /src/main/java/library/lending/domain/UserId.java: -------------------------------------------------------------------------------- 1 | package library.lending.domain; 2 | 3 | import org.springframework.util.Assert; 4 | 5 | import java.util.UUID; 6 | 7 | public record UserId(UUID id) { 8 | 9 | public UserId { 10 | Assert.notNull(id, "id must not be null"); 11 | } 12 | 13 | public UserId() { 14 | this(UUID.randomUUID()); 15 | } 16 | } 17 | -------------------------------------------------------------------------------- /src/main/resources/application.properties: -------------------------------------------------------------------------------- 1 | spring.application.name=library 2 | spring.jpa.hibernate.ddl-auto=create 3 | logging.level.sql=debug 4 | 5 | spring.datasource.password=password 6 | spring.datasource.username=postgres 7 | spring.datasource.url=jdbc:postgresql://localhost:5432/postgres -------------------------------------------------------------------------------- /src/test/java/library/LibraryApplicationTests.java: -------------------------------------------------------------------------------- 1 | package library; 2 | 3 | import org.junit.jupiter.api.Test; 4 | import org.springframework.boot.test.context.SpringBootTest; 5 | import org.springframework.modulith.core.ApplicationModules; 6 | 7 | @SpringBootTest 8 | class LibraryApplicationTests { 9 | 10 | @Test 11 | void contextLoads() { 12 | } 13 | 14 | @Test 15 | void verifyModules() { 16 | ApplicationModules.of(LibraryApplication.class).verify(); 17 | } 18 | 19 | } 20 | --------------------------------------------------------------------------------