Update maven-war-plugin version

* Refactor execute around the idiom

* fix checkstyle errors

Co-authored-by: Subhrodip Mohanta <hello@subho.xyz>

.mvn/wrapper/maven-wrapper.properties

@@ -1,25 +1,18 @@
-#
+# Licensed to the Apache Software Foundation (ASF) under one
-# The MIT License
+# or more contributor license agreements.  See the NOTICE file
-# Copyright © 2014-2021 Ilkka Seppälä
+# distributed with this work for additional information
-#
+# regarding copyright ownership.  The ASF licenses this file
-# Permission is hereby granted, free of charge, to any person obtaining a copy
+# to you under the Apache License, Version 2.0 (the
-# of this software and associated documentation files (the "Software"), to deal
+# "License"); you may not use this file except in compliance
-# in the Software without restriction, including without limitation the rights
+# with the License.  You may obtain a copy of the License at
-# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# 
-# copies of the Software, and to permit persons to whom the Software is
+#   http://www.apache.org/licenses/LICENSE-2.0
-# furnished to do so, subject to the following conditions:
+# 
-#
+# Unless required by applicable law or agreed to in writing,
-# The above copyright notice and this permission notice shall be included in
+# software distributed under the License is distributed on an
-# all copies or substantial portions of the Software.
+# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
-#
+# KIND, either express or implied.  See the License for the
-# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# specific language governing permissions and limitations
-# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# under the License.
-# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.8.4/apache-maven-3.8.4-bin.zip
-# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+wrapperUrl=https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar
-# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-# THE SOFTWARE.
-#
-
-distributionUrl=https://repo.maven.apache.org/maven2/org/apache/maven/apache-maven/3.6.3/apache-maven-3.6.3-bin.zip
-wrapperUrl=https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar

execute-around/README.md

@@ -17,10 +17,10 @@ the user to specify only what to do with the resource.
 
 ## Explanation
 
-Real world example
+Real-world example
 
-> We need to provide a class that can be used to write text strings to files. To make it easy for 
+> A class needs to be provided for writing text strings to files. To make it easy for 
-> the user we let our service class open and close the file automatically, the user only has to 
+> the user, the service class opens and closes the file automatically. The user only has to 
 > specify what is written into which file.       
 
 In plain words
@@ -35,35 +35,50 @@ In plain words
 
 **Programmatic Example**
 
-Let's introduce our file writer class.
+`SimpleFileWriter` class implements the Execute Around idiom. It takes `FileWriterAction` as a
+constructor argument allowing the user to specify what gets written into the file.
 
 ```java
 @FunctionalInterface
 public interface FileWriterAction {
-
   void writeFile(FileWriter writer) throws IOException;
-
 }
 
+@Slf4j
 public class SimpleFileWriter {
-
+    public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
-  public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
+        LOGGER.info("Opening the file");
-    try (var writer = new FileWriter(filename)) {
+        try (var writer = new FileWriter(filename)) {
-      action.writeFile(writer);
+            LOGGER.info("Executing the action");
+            action.writeFile(writer);
+            LOGGER.info("Closing the file");
+        }
     }
-  }
 }
 ```
 
-To utilize the file writer the following code is needed.
+The following code demonstrates how `SimpleFileWriter` is used. `Scanner` is used to print the file
+contents after the writing finishes.
 
 ```java
-    FileWriterAction writeHello = writer -> {
+FileWriterAction writeHello = writer -> {
-      writer.write("Hello");
+    writer.write("Gandalf was here");
-      writer.append(" ");
+};
-      writer.append("there!");
+new SimpleFileWriter("testfile.txt", writeHello);
-    };
+
-    new SimpleFileWriter("testfile.txt", writeHello);
+var scanner = new Scanner(new File("testfile.txt"));
+while (scanner.hasNextLine()) {
+LOGGER.info(scanner.nextLine());
+}
+```
+
+Here's the console output.
+
+```
+21:18:07.185 [main] INFO com.iluwatar.execute.around.SimpleFileWriter - Opening the file
+21:18:07.188 [main] INFO com.iluwatar.execute.around.SimpleFileWriter - Executing the action
+21:18:07.189 [main] INFO com.iluwatar.execute.around.SimpleFileWriter - Closing the file
+21:18:07.199 [main] INFO com.iluwatar.execute.around.App - Gandalf was here
 ```
 
 ## Class diagram
@@ -74,8 +89,7 @@ To utilize the file writer the following code is needed.
 
 Use the Execute Around idiom when
 
-* You use an API that requires methods to be called in pairs such as open/close or 
+* An API requires methods to be called in pairs such as open/close or allocate/deallocate.
-allocate/deallocate.
 
 ## Credits
 

execute-around/src/main/java/com/iluwatar/execute/around/App.java

@@ -23,10 +23,14 @@
 
 package com.iluwatar.execute.around;
 
+import java.io.File;
 import java.io.IOException;
+import java.util.Scanner;
+
+import lombok.extern.slf4j.Slf4j;
 
 /**
- * The Execute Around idiom specifies some code to be executed before and after a method. Typically
+ * The Execute Around idiom specifies executable code before and after a method. Typically
  * the idiom is used when the API has methods to be executed in pairs, such as resource
  * allocation/deallocation or lock acquisition/release.
  *
@@ -34,6 +38,7 @@ import java.io.IOException;
  * the user. The user specifies only what to do with the file by providing the {@link
  * FileWriterAction} implementation.
  */
+@Slf4j
 public class App {
 
   /**
@@ -41,11 +46,16 @@ public class App {
    */
   public static void main(String[] args) throws IOException {
 
+    // create the file writer and execute the custom action
     FileWriterAction writeHello = writer -> {
-      writer.write("Hello");
+      writer.write("Gandalf was here");
-      writer.append(" ");
-      writer.append("there!");
     };
     new SimpleFileWriter("testfile.txt", writeHello);
+
+    // print the file contents
+    var scanner = new Scanner(new File("testfile.txt"));
+    while (scanner.hasNextLine()) {
+      LOGGER.info(scanner.nextLine());
+    }
   }
 }

execute-around/src/main/java/com/iluwatar/execute/around/SimpleFileWriter.java

@@ -26,18 +26,24 @@ package com.iluwatar.execute.around;
 import java.io.FileWriter;
 import java.io.IOException;
 
+import lombok.extern.slf4j.Slf4j;
+
 /**
  * SimpleFileWriter handles opening and closing file for the user. The user only has to specify what
  * to do with the file resource through {@link FileWriterAction} parameter.
  */
+@Slf4j
 public class SimpleFileWriter {
 
   /**
    * Constructor.
    */
   public SimpleFileWriter(String filename, FileWriterAction action) throws IOException {
+    LOGGER.info("Opening the file");
     try (var writer = new FileWriter(filename)) {
+      LOGGER.info("Executing the action");
       action.writeFile(writer);
+      LOGGER.info("Closing the file");
     }
   }
 }

factory-kit/README.md

@@ -10,19 +10,115 @@ tags:
 ---
 
 ## Intent
+
 Define a factory of immutable content with separated builder and factory interfaces.
 
+## Explanation
+
+Real-world example
+
+> Imagine a magical weapon factory that can create any type of weapon wished for. When the factory
+> is unboxed, the master recites the weapon types needed to prepare it. After that, any of those
+> weapon types can be summoned in an instant. 
+
+In plain words
+
+> Factory kit is a configurable object builder.
+
+**Programmatic Example**
+
+Let's first define the simple `Weapon` hierarchy.
+
+```java
+public interface Weapon {
+}
+
+public enum WeaponType {
+    SWORD,
+    AXE,
+    BOW,
+    SPEAR
+}
+
+public class Sword implements Weapon {
+    @Override
+    public String toString() {
+        return "Sword";
+    }
+}
+
+// Axe, Bow, and Spear are defined similarly
+```
+
+Next, we define a functional interface that allows adding a builder with a name to the factory.
+
+```java
+public interface Builder {
+  void add(WeaponType name, Supplier<Weapon> supplier);
+}
+```
+
+The meat of the example is the `WeaponFactory` interface that effectively implements the factory
+kit pattern. The method `#factory` is used to configure the factory with the classes it needs to
+be able to construct. The method `#create` is then used to create object instances.
+
+```java
+public interface WeaponFactory {
+
+  static WeaponFactory factory(Consumer<Builder> consumer) {
+      var map = new HashMap<WeaponType, Supplier<Weapon>>();
+      consumer.accept(map::put);
+      return name -> map.get(name).get();
+  }
+    
+  Weapon create(WeaponType name);
+}
+```
+
+Now, we can show how `WeaponFactory` can be used.
+
+```java
+var factory = WeaponFactory.factory(builder -> {
+  builder.add(WeaponType.SWORD, Sword::new);
+  builder.add(WeaponType.AXE, Axe::new);
+  builder.add(WeaponType.SPEAR, Spear::new);
+  builder.add(WeaponType.BOW, Bow::new);
+});
+var list = new ArrayList<Weapon>();
+list.add(factory.create(WeaponType.AXE));
+list.add(factory.create(WeaponType.SPEAR));
+list.add(factory.create(WeaponType.SWORD));
+list.add(factory.create(WeaponType.BOW));
+list.stream().forEach(weapon -> LOGGER.info("{}", weapon.toString()));
+```
+
+Here is the console output when the example is run.
+
+```
+21:15:49.709 [main] INFO com.iluwatar.factorykit.App - Axe
+21:15:49.713 [main] INFO com.iluwatar.factorykit.App - Spear
+21:15:49.713 [main] INFO com.iluwatar.factorykit.App - Sword
+21:15:49.713 [main] INFO com.iluwatar.factorykit.App - Bow
+```
+
 ## Class diagram
+
 ![alt text](./etc/factory-kit.png "Factory Kit")
 
 ## Applicability
+
 Use the Factory Kit pattern when
 
-* a class can't anticipate the class of objects it must create
+* The factory class can't anticipate the types of objects it must create
-* you just want a new instance of a custom builder instead of the global one
+* A new instance of a custom builder is needed instead of a global one
-* you explicitly want to define types of objects, that factory can build
+* The types of objects that the factory can build need to be defined outside the class
-* you want a separated builder and creator interface
+* The builder and creator interfaces need to be separated
+
+## Related patterns
+
+* [Builder](https://java-design-patterns.com/patterns/builder/)
+* [Factory](https://java-design-patterns.com/patterns/factory/)
 
 ## Credits
 
-* [Design Pattern Reloaded by Remi Forax: ](https://www.youtube.com/watch?v=-k2X7guaArU)
+* [Design Pattern Reloaded by Remi Forax](https://www.youtube.com/watch?v=-k2X7guaArU)

factory-kit/src/main/java/com/iluwatar/factorykit/App.java

@@ -23,14 +23,16 @@
 
 package com.iluwatar.factorykit;
 
+import java.util.ArrayList;
+
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * Factory-kit is a creational pattern which defines a factory of immutable content with separated
+ * Factory kit is a creational pattern that defines a factory of immutable content with separated
  * builder and factory interfaces to deal with the problem of creating one of the objects specified
- * directly in the factory-kit instance.
+ * directly in the factory kit instance.
  *
- * <p>In the given example {@link WeaponFactory} represents the factory-kit, that contains four
+ * <p>In the given example {@link WeaponFactory} represents the factory kit, that contains four
  * {@link Builder}s for creating new objects of the classes implementing {@link Weapon} interface.
  *
  * <p>Each of them can be called with {@link WeaponFactory#create(WeaponType)} method, with
@@ -52,7 +54,11 @@ public class App {
       builder.add(WeaponType.SPEAR, Spear::new);
       builder.add(WeaponType.BOW, Bow::new);
     });
-    var axe = factory.create(WeaponType.AXE);
+    var list = new ArrayList<Weapon>();
-    LOGGER.info(axe.toString());
+    list.add(factory.create(WeaponType.AXE));
+    list.add(factory.create(WeaponType.SPEAR));
+    list.add(factory.create(WeaponType.SWORD));
+    list.add(factory.create(WeaponType.BOW));
+    list.stream().forEach(weapon -> LOGGER.info("{}", weapon.toString()));
   }
 }

model-view-viewmodel/pom.xml

@@ -41,7 +41,7 @@
     <zk.version>9.0.0</zk.version>
     <guava.version>19.0</guava.version>
     <jetty-maven-plugin.version>9.4.28.v20200408</jetty-maven-plugin.version>
-    <maven-war-plugin.version>2.1.1</maven-war-plugin.version>
+    <maven-war-plugin.version>3.3.2</maven-war-plugin.version>
     <maven-assembly-plugin.version>2.2</maven-assembly-plugin.version>
     <maven.build.timestamp.format>yyyy-MM-dd</maven.build.timestamp.format>
     <packname>-${project.version}-FL-${maven.build.timestamp}</packname>

mvnw

@@ -36,6 +36,10 @@
 
 if [ -z "$MAVEN_SKIP_RC" ] ; then
 
+  if [ -f /usr/local/etc/mavenrc ] ; then
+    . /usr/local/etc/mavenrc
+  fi
+
   if [ -f /etc/mavenrc ] ; then
     . /etc/mavenrc
   fi
@@ -145,7 +149,7 @@ if [ -z "$JAVACMD" ] ; then
       JAVACMD="$JAVA_HOME/bin/java"
     fi
   else
-    JAVACMD="`which java`"
+    JAVACMD="`\\unset -f command; \\command -v java`"
   fi
 fi
 
@@ -212,9 +216,9 @@ else
       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"
+      jarUrl="$MVNW_REPOURL/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
     else
-      jarUrl="https://repo.maven.apache.org/maven2/io/takari/maven-wrapper/0.5.6/maven-wrapper-0.5.6.jar"
+      jarUrl="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
     fi
     while IFS="=" read key value; do
       case "$key" in (wrapperUrl) jarUrl="$value"; break ;;
@@ -233,9 +237,9 @@ else
           echo "Found wget ... using wget"
         fi
         if [ -z "$MVNW_USERNAME" ] || [ -z "$MVNW_PASSWORD" ]; then
-            wget "$jarUrl" -O "$wrapperJarPath"
+            wget "$jarUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
         else
-            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath"
+            wget --http-user=$MVNW_USERNAME --http-password=$MVNW_PASSWORD "$jarUrl" -O "$wrapperJarPath" || rm -f "$wrapperJarPath"
         fi
     elif command -v curl > /dev/null; then
         if [ "$MVNW_VERBOSE" = true ]; then
@@ -305,6 +309,8 @@ WRAPPER_LAUNCHER=org.apache.maven.wrapper.MavenWrapperMain
 
 exec "$JAVACMD" \
   $MAVEN_OPTS \
+  $MAVEN_DEBUG_OPTS \
   -classpath "$MAVEN_PROJECTBASEDIR/.mvn/wrapper/maven-wrapper.jar" \
-  "-Dmaven.home=${M2_HOME}" "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
+  "-Dmaven.home=${M2_HOME}" \
+  "-Dmaven.multiModuleProjectDirectory=${MAVEN_PROJECTBASEDIR}" \
   ${WRAPPER_LAUNCHER} $MAVEN_CONFIG "$@"

mvnw.cmd

@@ -1,25 +1,21 @@
+@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 The MIT License
+@REM    http://www.apache.org/licenses/LICENSE-2.0
-@REM Copyright © 2014-2021 Ilkka Seppälä
-@REM
-@REM Permission is hereby granted, free of charge, to any person obtaining a copy
-@REM of this software and associated documentation files (the "Software"), to deal
-@REM in the Software without restriction, including without limitation the rights
-@REM to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
-@REM copies of the Software, and to permit persons to whom the Software is
-@REM furnished to do so, subject to the following conditions:
-@REM
-@REM The above copyright notice and this permission notice shall be included in
-@REM all copies or substantial portions of the Software.
-@REM
-@REM THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
-@REM IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
-@REM FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
-@REM AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
-@REM LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
-@REM OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
-@REM THE SOFTWARE.
 @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
@@ -50,8 +46,8 @@ 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 "%USERPROFILE%\mavenrc_pre.bat" call "%USERPROFILE%\mavenrc_pre.bat" %*
-if exist "%HOME%\mavenrc_pre.cmd" call "%HOME%\mavenrc_pre.cmd"
+if exist "%USERPROFILE%\mavenrc_pre.cmd" call "%USERPROFILE%\mavenrc_pre.cmd" %*
 :skipRcPre
 
 @setlocal
@@ -124,9 +120,9 @@ 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"
+set DOWNLOAD_URL="https://repo.maven.apache.org/maven2/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
 
-FOR /F "tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
+FOR /F "usebackq tokens=1,2 delims==" %%A IN ("%MAVEN_PROJECTBASEDIR%\.mvn\wrapper\maven-wrapper.properties") DO (
     IF "%%A"=="wrapperUrl" SET DOWNLOAD_URL=%%B
 )
 
@@ -138,7 +134,7 @@ if exist %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"
+        SET DOWNLOAD_URL="%MVNW_REPOURL%/org/apache/maven/wrapper/maven-wrapper/3.1.0/maven-wrapper-3.1.0.jar"
     )
     if "%MVNW_VERBOSE%" == "true" (
         echo Couldn't find %WRAPPER_JAR%, downloading it ...
@@ -162,7 +158,13 @@ if exist %WRAPPER_JAR% (
 @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% %*
+%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
 
@@ -172,15 +174,15 @@ set ERROR_CODE=1
 :end
 @endlocal & set ERROR_CODE=%ERROR_CODE%
 
-if not "%MAVEN_SKIP_RC%" == "" goto skipRcPost
+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 "%USERPROFILE%\mavenrc_post.bat" call "%USERPROFILE%\mavenrc_post.bat"
-if exist "%HOME%\mavenrc_post.cmd" call "%HOME%\mavenrc_post.cmd"
+if exist "%USERPROFILE%\mavenrc_post.cmd" call "%USERPROFILE%\mavenrc_post.cmd"
 :skipRcPost
 
 @REM pause the script if MAVEN_BATCH_PAUSE is set to 'on'
-if "%MAVEN_BATCH_PAUSE%" == "on" pause
+if "%MAVEN_BATCH_PAUSE%"=="on" pause
 
-if "%MAVEN_TERMINATE_CMD%" == "on" exit %ERROR_CODE%
+if "%MAVEN_TERMINATE_CMD%"=="on" exit %ERROR_CODE%
 
-exit /B %ERROR_CODE%
+cmd /C exit /B %ERROR_CODE%

naked-objects/pom.xml

@@ -150,7 +150,7 @@
         </plugin>
         <plugin>
           <artifactId>maven-war-plugin</artifactId>
-          <version>2.4</version>
+          <version>3.3.2</version>
         </plugin>
         <plugin>
           <groupId>org.mortbay.jetty</groupId>

thread-pool/README.md

@@ -18,11 +18,11 @@ threads and eliminating the latency of creating new threads.
 
 ## Explanation
 
-Real world example
+Real-world example
 
 > We have a large number of relatively short tasks at hand. We need to peel huge amounts of potatoes 
-> and serve mighty amount of coffee cups. Creating a new thread for each task would be a waste so we 
+> and serve a mighty amount of coffee cups. Creating a new thread for each task would be a waste so 
-> establish a thread pool.       
+> we establish a thread pool.       
 
 In plain words
 
@@ -99,7 +99,7 @@ public class PotatoPeelingTask extends Task {
 }
 ```
 
-Next we present a runnable `Worker` class that the thread pool will utilize to handle all the potato 
+Next, we present a runnable `Worker` class that the thread pool will utilize to handle all the potato 
 peeling and coffee making.
 
 ```java

throttling/README.md

@@ -16,10 +16,12 @@ Ensure that a given client is not able to access service resources more than the
 
 ## Explanation
 
-Real world example
+Real-world example
 
-> A large multinational corporation offers API to its customers. The API is rate-limited and each 
+> A young human and an old dwarf walk into a bar. They start ordering beers from the bartender.
-> customer can only make certain amount of calls per second.      
+> The bartender immediately sees that the young human shouldn't consume too many drinks too fast
+> and refuses to serve if enough time has not passed. For the old dwarf, the serving rate can
+> be higher.
 
 In plain words
 
@@ -33,30 +35,25 @@ In plain words
 
 **Programmatic Example**
 
-Tenant class presents the clients of the API. CallsCount tracks the number of API calls per tenant.
+`BarCustomer` class presents the clients of the `Bartender` API. `CallsCount` tracks the number of 
+calls per `BarCustomer`.
 
 ```java
-public class Tenant {
+public class BarCustomer {
 
-  private final String name;
+    @Getter
-  private final int allowedCallsPerSecond;
+    private final String name;
+    @Getter
+    private final int allowedCallsPerSecond;
 
-  public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
+    public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
-    if (allowedCallsPerSecond < 0) {
+        if (allowedCallsPerSecond < 0) {
-      throw new InvalidParameterException("Number of calls less than 0 not allowed");
+            throw new InvalidParameterException("Number of calls less than 0 not allowed");
+        }
+        this.name = name;
+        this.allowedCallsPerSecond = allowedCallsPerSecond;
+        callsCount.addTenant(name);
     }
-    this.name = name;
-    this.allowedCallsPerSecond = allowedCallsPerSecond;
-    callsCount.addTenant(name);
-  }
-
-  public String getName() {
-    return name;
-  }
-
-  public int getAllowedCallsPerSecond() {
-    return allowedCallsPerSecond;
-  }
 }
 
 @Slf4j
@@ -76,14 +73,14 @@ public final class CallsCount {
   }
 
   public void reset() {
-    LOGGER.debug("Resetting the map.");
     tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
+    LOGGER.info("reset counters");
   }
 }
 ```
 
-Next we introduce the service that the tenants are calling. To track the call count we use the 
+Next, the service that the tenants are calling is introduced. To track the call count, a throttler 
-throttler timer.
+timer is used.
 
 ```java
 public interface Throttler {
@@ -111,71 +108,103 @@ public class ThrottleTimerImpl implements Throttler {
     }, 0, throttlePeriod);
   }
 }
+```
 
-class B2BService {
+`Bartender` offers the `orderDrink` service to the `BarCustomer`s. The customers probably don't
+know that the beer serving rate is limited by their appearances.
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
+```java
-  private final CallsCount callsCount;
+class Bartender {
 
-  public B2BService(Throttler timer, CallsCount callsCount) {
+    private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
-    this.callsCount = callsCount;
+    private final CallsCount callsCount;
-    timer.start();
-  }
 
-  public int dummyCustomerApi(Tenant tenant) {
+    public Bartender(Throttler timer, CallsCount callsCount) {
-    var tenantName = tenant.getName();
+        this.callsCount = callsCount;
-    var count = callsCount.getCount(tenantName);
+        timer.start();
-    LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
-    if (count >= tenant.getAllowedCallsPerSecond()) {
-      LOGGER.error("API access per second limit reached for: {}", tenantName);
-      return -1;
     }
-    callsCount.incrementCount(tenantName);
-    return getRandomCustomerId();
-  }
 
-  private int getRandomCustomerId() {
+    public int orderDrink(BarCustomer barCustomer) {
-    return ThreadLocalRandom.current().nextInt(1, 10000);
+        var tenantName = barCustomer.getName();
-  }
+        var count = callsCount.getCount(tenantName);
+        if (count >= barCustomer.getAllowedCallsPerSecond()) {
+            LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
+            return -1;
+        }
+        callsCount.incrementCount(tenantName);
+        LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count+1);
+        return getRandomCustomerId();
+    }
+
+    private int getRandomCustomerId() {
+        return ThreadLocalRandom.current().nextInt(1, 10000);
+    }
 }
 ```
 
-Now we are ready to see the full example in action. Tenant Adidas is rate-limited to 5 calls per 
+Now it is possible to see the full example in action. `BarCustomer` young human is rate-limited to 2 
-second and Nike to 6.
+calls per second and the old dwarf to 4.
 
 ```java
-  public static void main(String[] args) {
+public static void main(String[] args) {
     var callsCount = new CallsCount();
-    var adidas = new Tenant("Adidas", 5, callsCount);
+    var human = new BarCustomer("young human", 2, callsCount);
-    var nike = new Tenant("Nike", 6, callsCount);
+    var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
 
     var executorService = Executors.newFixedThreadPool(2);
-    executorService.execute(() -> makeServiceCalls(adidas, callsCount));
-    executorService.execute(() -> makeServiceCalls(nike, callsCount));
-    executorService.shutdown();
-    
-    try {
-      executorService.awaitTermination(10, TimeUnit.SECONDS);
-    } catch (InterruptedException e) {
-      LOGGER.error("Executor Service terminated: {}", e.getMessage());
-    }
-  }
 
-  private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
+    executorService.execute(() -> makeServiceCalls(human, callsCount));
-    var timer = new ThrottleTimerImpl(10, callsCount);
+    executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
-    var service = new B2BService(timer, callsCount);
+
+    executorService.shutdown();
+    try {
+        executorService.awaitTermination(10, TimeUnit.SECONDS);
+    } catch (InterruptedException e) {
+        LOGGER.error("Executor service terminated: {}", e.getMessage());
+    }
+}
+
+private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
+    var timer = new ThrottleTimerImpl(1000, callsCount);
+    var service = new Bartender(timer, callsCount);
     // Sleep is introduced to keep the output in check and easy to view and analyze the results.
-    IntStream.range(0, 20).forEach(i -> {
+    IntStream.range(0, 50).forEach(i -> {
-      service.dummyCustomerApi(tenant);
+        service.orderDrink(barCustomer);
-      try {
+        try {
-        Thread.sleep(1);
+            Thread.sleep(100);
-      } catch (InterruptedException e) {
+        } catch (InterruptedException e) {
-        LOGGER.error("Thread interrupted: {}", e.getMessage());
+            LOGGER.error("Thread interrupted: {}", e.getMessage());
-      }
+        }
     });
-  }
+}
 ```
 
+An excerpt from the example's console output:
+
+```
+18:46:36.218 [Timer-0] INFO com.iluwatar.throttling.CallsCount - reset counters
+18:46:36.218 [Timer-1] INFO com.iluwatar.throttling.CallsCount - reset counters
+18:46:36.242 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [1 consumed] 
+18:46:36.242 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [1 consumed] 
+18:46:36.342 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [2 consumed] 
+18:46:36.342 [pool-1-thread-1] DEBUG com.iluwatar.throttling.Bartender - Serving beer to young human : [2 consumed] 
+18:46:36.443 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.443 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [3 consumed] 
+18:46:36.544 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.544 [pool-1-thread-2] DEBUG com.iluwatar.throttling.Bartender - Serving beer to dwarf soldier : [4 consumed] 
+18:46:36.645 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.645 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.745 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.745 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.846 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:36.846 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.947 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:36.947 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:37.048 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+18:46:37.048 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:37.148 [pool-1-thread-1] ERROR com.iluwatar.throttling.Bartender - I'm sorry young human, you've had enough for today!
+18:46:37.148 [pool-1-thread-2] ERROR com.iluwatar.throttling.Bartender - I'm sorry dwarf soldier, you've had enough for today!
+```
 
 ## Class diagram
 
@@ -185,7 +214,7 @@ second and Nike to 6.
 
 The Throttling pattern should be used:
 
-* When a service access needs to be restricted to not have high impacts on the performance of the service.
+* When service access needs to be restricted not to have high impact on the performance of the service.
 * When multiple clients are consuming the same service resources and restriction has to be made according to the usage per client.
 
 ## Credits

throttling/src/main/java/com/iluwatar/throttling/App.java

@@ -34,11 +34,11 @@ import lombok.extern.slf4j.Slf4j;
  * complete service by users or a particular tenant. This can allow systems to continue to function
  * and meet service level agreements, even when an increase in demand places load on resources.
  * <p>
- * In this example we have ({@link App}) as the initiating point of the service. This is a time
+ * In this example there is a {@link Bartender} serving beer to {@link BarCustomer}s. This is a time
  * based throttling, i.e. only a certain number of calls are allowed per second.
  * </p>
- * ({@link Tenant}) is the Tenant POJO class with which many tenants can be created ({@link
+ * ({@link BarCustomer}) is the service tenant class having a name and the number of calls allowed.
- * B2BService}) is the service which is consumed by the tenants and is throttled.
+ * ({@link Bartender}) is the service which is consumed by the tenants and is throttled.
  */
 @Slf4j
 public class App {
@@ -50,33 +50,35 @@ public class App {
    */
   public static void main(String[] args) {
     var callsCount = new CallsCount();
-    var adidas = new Tenant("Adidas", 5, callsCount);
+    var human = new BarCustomer("young human", 2, callsCount);
-    var nike = new Tenant("Nike", 6, callsCount);
+    var dwarf = new BarCustomer("dwarf soldier", 4, callsCount);
 
     var executorService = Executors.newFixedThreadPool(2);
 
-    executorService.execute(() -> makeServiceCalls(adidas, callsCount));
+    executorService.execute(() -> makeServiceCalls(human, callsCount));
-    executorService.execute(() -> makeServiceCalls(nike, callsCount));
+    executorService.execute(() -> makeServiceCalls(dwarf, callsCount));
 
     executorService.shutdown();
     try {
-      executorService.awaitTermination(10, TimeUnit.SECONDS);
+      if (!executorService.awaitTermination(10, TimeUnit.SECONDS)) {
+        executorService.shutdownNow();
+      }
     } catch (InterruptedException e) {
-      LOGGER.error("Executor Service terminated: {}", e.getMessage());
+      executorService.shutdownNow();
     }
   }
 
   /**
-   * Make calls to the B2BService dummy API.
+   * Make calls to the bartender.
    */
-  private static void makeServiceCalls(Tenant tenant, CallsCount callsCount) {
+  private static void makeServiceCalls(BarCustomer barCustomer, CallsCount callsCount) {
-    var timer = new ThrottleTimerImpl(10, callsCount);
+    var timer = new ThrottleTimerImpl(1000, callsCount);
-    var service = new B2BService(timer, callsCount);
+    var service = new Bartender(timer, callsCount);
     // Sleep is introduced to keep the output in check and easy to view and analyze the results.
-    IntStream.range(0, 20).forEach(i -> {
+    IntStream.range(0, 50).forEach(i -> {
-      service.dummyCustomerApi(tenant);
+      service.orderDrink(barCustomer);
       try {
-        Thread.sleep(1);
+        Thread.sleep(100);
       } catch (InterruptedException e) {
         LOGGER.error("Thread interrupted: {}", e.getMessage());
       }

throttling/src/main/java/com/iluwatar/throttling/BarCustomer.java

@@ -25,22 +25,26 @@ package com.iluwatar.throttling;
 
 import java.security.InvalidParameterException;
 
-/**
+import lombok.Getter;
- * A Pojo class to create a basic Tenant with the allowed calls per second.
- */
-public class Tenant {
 
+/**
+ * BarCustomer is a tenant with a name and a number of allowed calls per second.
+ */
+public class BarCustomer {
+
+  @Getter
   private final String name;
+  @Getter
   private final int allowedCallsPerSecond;
 
   /**
    * Constructor.
    *
-   * @param name                  Name of the tenant
+   * @param name Name of the BarCustomer
-   * @param allowedCallsPerSecond The number of calls allowed for a particular tenant.
+   * @param allowedCallsPerSecond The number of calls allowed for this particular tenant.
    * @throws InvalidParameterException If number of calls is less than 0, throws exception.
    */
-  public Tenant(String name, int allowedCallsPerSecond, CallsCount callsCount) {
+  public BarCustomer(String name, int allowedCallsPerSecond, CallsCount callsCount) {
     if (allowedCallsPerSecond < 0) {
       throw new InvalidParameterException("Number of calls less than 0 not allowed");
     }
@@ -48,12 +52,4 @@ public class Tenant {
     this.allowedCallsPerSecond = allowedCallsPerSecond;
     callsCount.addTenant(name);
   }
-
-  public String getName() {
-    return name;
-  }
-
-  public int getAllowedCallsPerSecond() {
-    return allowedCallsPerSecond;
-  }
 }

throttling/src/main/java/com/iluwatar/throttling/Bartender.java

@@ -29,33 +29,32 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 /**
- * A service which accepts a tenant and throttles the resource based on the time given to the
+ * Bartender is a service which accepts a BarCustomer (tenant) and throttles
- * tenant.
+ * the resource based on the time given to the tenant.
  */
-class B2BService {
+class Bartender {
 
-  private static final Logger LOGGER = LoggerFactory.getLogger(B2BService.class);
+  private static final Logger LOGGER = LoggerFactory.getLogger(Bartender.class);
   private final CallsCount callsCount;
 
-  public B2BService(Throttler timer, CallsCount callsCount) {
+  public Bartender(Throttler timer, CallsCount callsCount) {
     this.callsCount = callsCount;
     timer.start();
   }
 
   /**
-   * Calls dummy customer api.
+   * Orders a drink from the bartender.
-   *
    * @return customer id which is randomly generated
    */
-  public int dummyCustomerApi(Tenant tenant) {
+  public int orderDrink(BarCustomer barCustomer) {
-    var tenantName = tenant.getName();
+    var tenantName = barCustomer.getName();
     var count = callsCount.getCount(tenantName);
-    LOGGER.debug("Counter for {} : {} ", tenant.getName(), count);
+    if (count >= barCustomer.getAllowedCallsPerSecond()) {
-    if (count >= tenant.getAllowedCallsPerSecond()) {
+      LOGGER.error("I'm sorry {}, you've had enough for today!", tenantName);
-      LOGGER.error("API access per second limit reached for: {}", tenantName);
       return -1;
     }
     callsCount.incrementCount(tenantName);
+    LOGGER.debug("Serving beer to {} : [{} consumed] ", barCustomer.getName(), count + 1);
     return getRandomCustomerId();
   }
 

throttling/src/main/java/com/iluwatar/throttling/CallsCount.java

@@ -69,7 +69,7 @@ public final class CallsCount {
    * Resets the count of all the tenants in the map.
    */
   public void reset() {
-    LOGGER.debug("Resetting the map.");
     tenantCallsCount.replaceAll((k, v) -> new AtomicLong(0));
+    LOGGER.info("reset counters");
   }
 }

throttling/src/test/java/com/iluwatar/throttling/BarCustomerTest.java

@@ -23,20 +23,21 @@
 
 package com.iluwatar.throttling;
 
-import static org.junit.jupiter.api.Assertions.assertThrows;
+import org.junit.jupiter.api.Test;
 
 import java.security.InvalidParameterException;
-import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
 /**
  * TenantTest to test the creation of Tenant with valid parameters.
  */
-public class TenantTest {
+public class BarCustomerTest {
 
   @Test
   void constructorTest() {
     assertThrows(InvalidParameterException.class, () -> {
-      new Tenant("FailTenant", -1, new CallsCount());
+      new BarCustomer("sirBrave", -1, new CallsCount());
     });
   }
 }

throttling/src/test/java/com/iluwatar/throttling/BartenderTest.java

@@ -32,19 +32,18 @@ import org.junit.jupiter.api.Test;
 /**
  * B2BServiceTest class to test the B2BService
  */
-public class B2BServiceTest {
+public class BartenderTest {
 
   private final CallsCount callsCount = new CallsCount();
 
   @Test
   void dummyCustomerApiTest() {
-    var tenant = new Tenant("testTenant", 2, callsCount);
+    var tenant = new BarCustomer("pirate", 2, callsCount);
     // In order to assure that throttling limits will not be reset, we use an empty throttling implementation
-    var timer = (Throttler) () -> {
+    var timer = (Throttler) () -> {};
-    };
+    var service = new Bartender(timer, callsCount);
-    var service = new B2BService(timer, callsCount);
 
-    IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::dummyCustomerApi);
+    IntStream.range(0, 5).mapToObj(i -> tenant).forEach(service::orderDrink);
     var counter = callsCount.getCount(tenant.getName());
     assertEquals(2, counter, "Counter limit must be reached");
   }

unit-of-work/README.md

@@ -12,20 +12,20 @@ tags:
 
 ## Intent
 
-When a business transaction is completed, all the the updates are sent as one big unit of work to be 
+When a business transaction is completed, all the updates are sent as one big unit of work to be 
 persisted in one go to minimize database round-trips. 
 
 ## Explanation
 
-Real world example
+Real-world example
 
-> We have a database containing student information. Administrators all over the country are 
+> Arms dealer has a database containing weapon information. Merchants all over the town are 
-> constantly updating this information and it causes high load on the database server. To make the 
+> constantly updating this information and it causes a high load on the database server. To make the 
 > load more manageable we apply to Unit of Work pattern to send many small updates in batches.       
 
 In plain words
 
-> Unit of Work merges many small database updates in single batch to optimize the number of 
+> Unit of Work merges many small database updates in a single batch to optimize the number of 
 > round-trips. 
 
 [MartinFowler.com](https://martinfowler.com/eaaCatalog/unitOfWork.html) says
@@ -35,37 +35,20 @@ In plain words
 
 **Programmatic Example**
 
-Here's the `Student` entity that is being persisted to the database.
+Here's the `Weapon` entity that is being persisted in the database.
 
 ```java
-public class Student {
+@Getter
-  private final Integer id;
+@RequiredArgsConstructor
-  private final String name;
+public class Weapon {
-  private final String address;
+    private final Integer id;
-
+    private final String name;
-  public Student(Integer id, String name, String address) {
-    this.id = id;
-    this.name = name;
-    this.address = address;
-  }
-
-  public String getName() {
-    return name;
-  }
-
-  public Integer getId() {
-    return id;
-  }
-
-  public String getAddress() {
-    return address;
-  }
 }
 ```
 
-The essence of the implementation is the `StudentRepository` implementing the Unit of Work pattern. 
+The essence of the implementation is the `ArmsDealer` implementing the Unit of Work pattern. 
 It maintains a map of database operations (`context`) that need to be done and when `commit` is 
-called it applies them in single batch.
+called it applies them in a single batch.
 
 ```java
 public interface IUnitOfWork<T> {
@@ -84,96 +67,117 @@ public interface IUnitOfWork<T> {
 }
 
 @Slf4j
-public class StudentRepository implements IUnitOfWork<Student> {
+@RequiredArgsConstructor
+public class ArmsDealer implements IUnitOfWork<Weapon> {
 
-  private final Map<String, List<Student>> context;
+    private final Map<String, List<Weapon>> context;
-  private final StudentDatabase studentDatabase;
+    private final WeaponDatabase weaponDatabase;
 
-  public StudentRepository(Map<String, List<Student>> context, StudentDatabase studentDatabase) {
+    @Override
-    this.context = context;
+    public void registerNew(Weapon weapon) {
-    this.studentDatabase = studentDatabase;
+        LOGGER.info("Registering {} for insert in context.", weapon.getName());
-  }
+        register(weapon, UnitActions.INSERT.getActionValue());
-
-  @Override
-  public void registerNew(Student student) {
-    LOGGER.info("Registering {} for insert in context.", student.getName());
-    register(student, IUnitOfWork.INSERT);
-  }
-
-  @Override
-  public void registerModified(Student student) {
-    LOGGER.info("Registering {} for modify in context.", student.getName());
-    register(student, IUnitOfWork.MODIFY);
-
-  }
-
-  @Override
-  public void registerDeleted(Student student) {
-    LOGGER.info("Registering {} for delete in context.", student.getName());
-    register(student, IUnitOfWork.DELETE);
-  }
-
-  private void register(Student student, String operation) {
-    var studentsToOperate = context.get(operation);
-    if (studentsToOperate == null) {
-      studentsToOperate = new ArrayList<>();
-    }
-    studentsToOperate.add(student);
-    context.put(operation, studentsToOperate);
-  }
-
-  @Override
-  public void commit() {
-    if (context == null || context.size() == 0) {
-      return;
-    }
-    LOGGER.info("Commit started");
-    if (context.containsKey(IUnitOfWork.INSERT)) {
-      commitInsert();
     }
 
-    if (context.containsKey(IUnitOfWork.MODIFY)) {
+    @Override
-      commitModify();
+    public void registerModified(Weapon weapon) {
-    }
+        LOGGER.info("Registering {} for modify in context.", weapon.getName());
-    if (context.containsKey(IUnitOfWork.DELETE)) {
+        register(weapon, UnitActions.MODIFY.getActionValue());
-      commitDelete();
-    }
-    LOGGER.info("Commit finished.");
-  }
 
-  private void commitInsert() {
-    var studentsToBeInserted = context.get(IUnitOfWork.INSERT);
-    for (var student : studentsToBeInserted) {
-      LOGGER.info("Saving {} to database.", student.getName());
-      studentDatabase.insert(student);
     }
-  }
 
-  private void commitModify() {
+    @Override
-    var modifiedStudents = context.get(IUnitOfWork.MODIFY);
+    public void registerDeleted(Weapon weapon) {
-    for (var student : modifiedStudents) {
+        LOGGER.info("Registering {} for delete in context.", weapon.getName());
-      LOGGER.info("Modifying {} to database.", student.getName());
+        register(weapon, UnitActions.DELETE.getActionValue());
-      studentDatabase.modify(student);
     }
-  }
 
-  private void commitDelete() {
+    private void register(Weapon weapon, String operation) {
-    var deletedStudents = context.get(IUnitOfWork.DELETE);
+        var weaponsToOperate = context.get(operation);
-    for (var student : deletedStudents) {
+        if (weaponsToOperate == null) {
-      LOGGER.info("Deleting {} to database.", student.getName());
+            weaponsToOperate = new ArrayList<>();
-      studentDatabase.delete(student);
+        }
+        weaponsToOperate.add(weapon);
+        context.put(operation, weaponsToOperate);
+    }
+
+    /**
+     * All UnitOfWork operations are batched and executed together on commit only.
+     */
+    @Override
+    public void commit() {
+        if (context == null || context.size() == 0) {
+            return;
+        }
+        LOGGER.info("Commit started");
+        if (context.containsKey(UnitActions.INSERT.getActionValue())) {
+            commitInsert();
+        }
+
+        if (context.containsKey(UnitActions.MODIFY.getActionValue())) {
+            commitModify();
+        }
+        if (context.containsKey(UnitActions.DELETE.getActionValue())) {
+            commitDelete();
+        }
+        LOGGER.info("Commit finished.");
+    }
+
+    private void commitInsert() {
+        var weaponsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
+        for (var weapon : weaponsToBeInserted) {
+            LOGGER.info("Inserting a new weapon {} to sales rack.", weapon.getName());
+            weaponDatabase.insert(weapon);
+        }
+    }
+
+    private void commitModify() {
+        var modifiedWeapons = context.get(UnitActions.MODIFY.getActionValue());
+        for (var weapon : modifiedWeapons) {
+            LOGGER.info("Scheduling {} for modification work.", weapon.getName());
+            weaponDatabase.modify(weapon);
+        }
+    }
+
+    private void commitDelete() {
+        var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
+        for (var weapon : deletedWeapons) {
+            LOGGER.info("Scrapping {}.", weapon.getName());
+            weaponDatabase.delete(weapon);
+        }
     }
-  }
 }
 ```
 
-Finally, here's how we use the `StudentRepository` and `commit` the transaction.
+Here is how the whole app is put together.
 
 ```java
-    studentRepository.registerNew(ram);
+// create some weapons
-    studentRepository.registerModified(shyam);
+var enchantedHammer = new Weapon(1, "enchanted hammer");
-    studentRepository.registerDeleted(gopi);
+var brokenGreatSword = new Weapon(2, "broken great sword");
-    studentRepository.commit();
+var silverTrident = new Weapon(3, "silver trident");
+
+// create repository
+var weaponRepository = new ArmsDealer(new HashMap<String, List<Weapon>>(), new WeaponDatabase());
+
+// perform operations on the weapons
+weaponRepository.registerNew(enchantedHammer);
+weaponRepository.registerModified(silverTrident);
+weaponRepository.registerDeleted(brokenGreatSword);
+weaponRepository.commit();
+```
+
+Here is the console output.
+
+```
+21:39:21.984 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering enchanted hammer for insert in context.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering silver trident for modify in context.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Registering broken great sword for delete in context.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Commit started
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Inserting a new weapon enchanted hammer to sales rack.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Scheduling silver trident for modification work.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Scrapping broken great sword.
+21:39:21.989 [main] INFO com.iluwatar.unitofwork.ArmsDealer - Commit finished.
 ```
 
 ## Class diagram
@@ -186,7 +190,7 @@ Use the Unit Of Work pattern when
 
 * To optimize the time taken for database transactions.
 * To send changes to database as a unit of work which ensures atomicity of the transaction.
-* To reduce number of database calls.
+* To reduce the number of database calls.
 
 ## Tutorials
 

unit-of-work/etc/unit-of-work.ucls

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <class-diagram version="1.2.1" icons="true" always-add-relationships="false" generalizations="true" realizations="true" 
   associations="true" dependencies="false" nesting-relationships="true" router="FAN">  
-  <class id="1" language="java" name="com.iluwatar.unitofwork.StudentDatabase" project="unit-of-work" 
+  <class id="1" language="java" name="com.iluwatar.unitofwork.WeaponDatabase" project="unit-of-work"
     file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentDatabase.java" binary="false" corner="BOTTOM_RIGHT">    
     <position height="-1" width="-1" x="170" y="406"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 
@@ -28,7 +28,7 @@
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </class>  
-  <class id="4" language="java" name="com.iluwatar.unitofwork.StudentRepository" project="unit-of-work" 
+  <class id="4" language="java" name="com.iluwatar.unitofwork.ArmsDealer" project="unit-of-work"
     file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/StudentRepository.java" binary="false" 
     corner="BOTTOM_RIGHT">    
     <position height="-1" width="-1" x="377" y="166"/>    
@@ -38,7 +38,7 @@
       <operations public="true" package="true" protected="true" private="true" static="true"/>    
     </display>  
   </class>  
-  <class id="5" language="java" name="com.iluwatar.unitofwork.Student" project="unit-of-work" 
+  <class id="5" language="java" name="com.iluwatar.unitofwork.Weapon" project="unit-of-work"
     file="/unit-of-work/src/main/java/com/iluwatar/unitofwork/Student.java" binary="false" corner="BOTTOM_RIGHT">    
     <position height="-1" width="-1" x="696" y="130"/>    
     <display autosize="true" stereotype="true" package="true" initial-value="false" signature="true" 

unit-of-work/src/main/java/com/iluwatar/unitofwork/App.java

@@ -27,7 +27,7 @@ import java.util.HashMap;
 import java.util.List;
 
 /**
- * {@link App} Application for managing student data.
+ * {@link App} Application demonstrating unit of work pattern.
  */
 public class App {
   /**
@@ -37,17 +37,19 @@ public class App {
    */
 
   public static void main(String[] args) {
-    var ram = new Student(1, "Ram", "Street 9, Cupertino");
+    // create some weapons
-    var shyam = new Student(2, "Shyam", "Z bridge, Pune");
+    var enchantedHammer = new Weapon(1, "enchanted hammer");
-    var gopi = new Student(3, "Gopi", "Street 10, Mumbai");
+    var brokenGreatSword = new Weapon(2, "broken great sword");
+    var silverTrident = new Weapon(3, "silver trident");
 
-    var context = new HashMap<String, List<Student>>();
+    // create repository
-    var studentDatabase = new StudentDatabase();
+    var weaponRepository = new ArmsDealer(new HashMap<String, List<Weapon>>(),
-    var studentRepository = new StudentRepository(context, studentDatabase);
+            new WeaponDatabase());
 
-    studentRepository.registerNew(ram);
+    // perform operations on the weapons
-    studentRepository.registerModified(shyam);
+    weaponRepository.registerNew(enchantedHammer);
-    studentRepository.registerDeleted(gopi);
+    weaponRepository.registerModified(silverTrident);
-    studentRepository.commit();
+    weaponRepository.registerDeleted(brokenGreatSword);
+    weaponRepository.commit();
   }
 }

unit-of-work/src/main/java/com/iluwatar/unitofwork/ArmsDealer.java

@@ -30,41 +30,41 @@ import lombok.RequiredArgsConstructor;
 import lombok.extern.slf4j.Slf4j;
 
 /**
- * {@link StudentRepository} Student database repository. supports unit of work for student data.
+ * {@link ArmsDealer} Weapon repository that supports unit of work for weapons.
  */
 @Slf4j
 @RequiredArgsConstructor
-public class StudentRepository implements IUnitOfWork<Student> {
+public class ArmsDealer implements IUnitOfWork<Weapon> {
 
-  private final Map<String, List<Student>> context;
+  private final Map<String, List<Weapon>> context;
-  private final StudentDatabase studentDatabase;
+  private final WeaponDatabase weaponDatabase;
 
   @Override
-  public void registerNew(Student student) {
+  public void registerNew(Weapon weapon) {
-    LOGGER.info("Registering {} for insert in context.", student.getName());
+    LOGGER.info("Registering {} for insert in context.", weapon.getName());
-    register(student, UnitActions.INSERT.getActionValue());
+    register(weapon, UnitActions.INSERT.getActionValue());
   }
 
   @Override
-  public void registerModified(Student student) {
+  public void registerModified(Weapon weapon) {
-    LOGGER.info("Registering {} for modify in context.", student.getName());
+    LOGGER.info("Registering {} for modify in context.", weapon.getName());
-    register(student, UnitActions.MODIFY.getActionValue());
+    register(weapon, UnitActions.MODIFY.getActionValue());
 
   }
 
   @Override
-  public void registerDeleted(Student student) {
+  public void registerDeleted(Weapon weapon) {
-    LOGGER.info("Registering {} for delete in context.", student.getName());
+    LOGGER.info("Registering {} for delete in context.", weapon.getName());
-    register(student, UnitActions.DELETE.getActionValue());
+    register(weapon, UnitActions.DELETE.getActionValue());
   }
 
-  private void register(Student student, String operation) {
+  private void register(Weapon weapon, String operation) {
-    var studentsToOperate = context.get(operation);
+    var weaponsToOperate = context.get(operation);
-    if (studentsToOperate == null) {
+    if (weaponsToOperate == null) {
-      studentsToOperate = new ArrayList<>();
+      weaponsToOperate = new ArrayList<>();
     }
-    studentsToOperate.add(student);
+    weaponsToOperate.add(weapon);
-    context.put(operation, studentsToOperate);
+    context.put(operation, weaponsToOperate);
   }
 
   /**
@@ -90,26 +90,26 @@ public class StudentRepository implements IUnitOfWork<Student> {
   }
 
   private void commitInsert() {
-    var studentsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
+    var weaponsToBeInserted = context.get(UnitActions.INSERT.getActionValue());
-    for (var student : studentsToBeInserted) {
+    for (var weapon : weaponsToBeInserted) {
-      LOGGER.info("Saving {} to database.", student.getName());
+      LOGGER.info("Inserting a new weapon {} to sales rack.", weapon.getName());
-      studentDatabase.insert(student);
+      weaponDatabase.insert(weapon);
     }
   }
 
   private void commitModify() {
-    var modifiedStudents = context.get(UnitActions.MODIFY.getActionValue());
+    var modifiedWeapons = context.get(UnitActions.MODIFY.getActionValue());
-    for (var student : modifiedStudents) {
+    for (var weapon : modifiedWeapons) {
-      LOGGER.info("Modifying {} to database.", student.getName());
+      LOGGER.info("Scheduling {} for modification work.", weapon.getName());
-      studentDatabase.modify(student);
+      weaponDatabase.modify(weapon);
     }
   }
 
   private void commitDelete() {
-    var deletedStudents = context.get(UnitActions.DELETE.getActionValue());
+    var deletedWeapons = context.get(UnitActions.DELETE.getActionValue());
-    for (var student : deletedStudents) {
+    for (var weapon : deletedWeapons) {
-      LOGGER.info("Deleting {} to database.", student.getName());
+      LOGGER.info("Scrapping {}.", weapon.getName());
-      studentDatabase.delete(student);
+      weaponDatabase.delete(weapon);
     }
   }
 }

unit-of-work/src/main/java/com/iluwatar/unitofwork/Weapon.java

@@ -27,14 +27,12 @@ import lombok.Getter;
 import lombok.RequiredArgsConstructor;
 
 /**
- * {@link Student} is an entity.
+ * {@link Weapon} is an entity.
  */
 @Getter
 @RequiredArgsConstructor
-public class Student {
+public class Weapon {
 
   private final Integer id;
   private final String name;
-  private final String address;
-
 }

unit-of-work/src/main/java/com/iluwatar/unitofwork/WeaponDatabase.java

@@ -24,19 +24,19 @@
 package com.iluwatar.unitofwork;
 
 /**
- * Act as Database for student records.
+ * Act as database for weapon records.
  */
-public class StudentDatabase {
+public class WeaponDatabase {
 
-  public void insert(Student student) {
+  public void insert(Weapon weapon) {
     //Some insert logic to DB
   }
 
-  public void modify(Student student) {
+  public void modify(Weapon weapon) {
     //Some modify logic to DB
   }
 
-  public void delete(Student student) {
+  public void delete(Weapon weapon) {
     //Some delete logic to DB
   }
 }

unit-of-work/src/test/java/com/iluwatar/unitofwork/ArmsDealerTest.java

@@ -36,102 +36,102 @@ import java.util.Map;
 import org.junit.jupiter.api.Test;
 
 /**
- * tests {@link StudentRepository}
+ * tests {@link ArmsDealer}
  */
 
-class StudentRepositoryTest {
+class ArmsDealerTest {
-  private final Student student1 = new Student(1, "Ram", "street 9, cupertino");
+  private final Weapon weapon1 = new Weapon(1, "battle ram");
-  private final Student student2 = new Student(1, "Sham", "Z bridge, pune");
+  private final Weapon weapon2 = new Weapon(1, "wooden lance");
 
-  private final Map<String, List<Student>> context = new HashMap<>();
+  private final Map<String, List<Weapon>> context = new HashMap<>();
-  private final StudentDatabase studentDatabase = mock(StudentDatabase.class);
+  private final WeaponDatabase weaponDatabase = mock(WeaponDatabase.class);
-  private final StudentRepository studentRepository = new StudentRepository(context, studentDatabase);;
+  private final ArmsDealer armsDealer = new ArmsDealer(context, weaponDatabase);;
 
   @Test
   void shouldSaveNewStudentWithoutWritingToDb() {
-    studentRepository.registerNew(student1);
+    armsDealer.registerNew(weapon1);
-    studentRepository.registerNew(student2);
+    armsDealer.registerNew(weapon2);
 
     assertEquals(2, context.get(UnitActions.INSERT.getActionValue()).size());
-    verifyNoMoreInteractions(studentDatabase);
+    verifyNoMoreInteractions(weaponDatabase);
   }
 
   @Test
   void shouldSaveDeletedStudentWithoutWritingToDb() {
-    studentRepository.registerDeleted(student1);
+    armsDealer.registerDeleted(weapon1);
-    studentRepository.registerDeleted(student2);
+    armsDealer.registerDeleted(weapon2);
 
     assertEquals(2, context.get(UnitActions.DELETE.getActionValue()).size());
-    verifyNoMoreInteractions(studentDatabase);
+    verifyNoMoreInteractions(weaponDatabase);
   }
 
   @Test
   void shouldSaveModifiedStudentWithoutWritingToDb() {
-    studentRepository.registerModified(student1);
+    armsDealer.registerModified(weapon1);
-    studentRepository.registerModified(student2);
+    armsDealer.registerModified(weapon2);
 
     assertEquals(2, context.get(UnitActions.MODIFY.getActionValue()).size());
-    verifyNoMoreInteractions(studentDatabase);
+    verifyNoMoreInteractions(weaponDatabase);
   }
 
   @Test
   void shouldSaveAllLocalChangesToDb() {
-    context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
+    context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
-    context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
+    context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
-    context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
+    context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
 
-    studentRepository.commit();
+    armsDealer.commit();
 
-    verify(studentDatabase, times(1)).insert(student1);
+    verify(weaponDatabase, times(1)).insert(weapon1);
-    verify(studentDatabase, times(1)).modify(student1);
+    verify(weaponDatabase, times(1)).modify(weapon1);
-    verify(studentDatabase, times(1)).delete(student1);
+    verify(weaponDatabase, times(1)).delete(weapon1);
   }
 
   @Test
   void shouldNotWriteToDbIfContextIsNull() {
-    var studentRepository = new StudentRepository(null, studentDatabase);
+    var weaponRepository = new ArmsDealer(null, weaponDatabase);
 
-    studentRepository.commit();
+    weaponRepository.commit();
 
-    verifyNoMoreInteractions(studentDatabase);
+    verifyNoMoreInteractions(weaponDatabase);
   }
 
   @Test
   void shouldNotWriteToDbIfNothingToCommit() {
-    var studentRepository = new StudentRepository(new HashMap<>(), studentDatabase);
+    var weaponRepository = new ArmsDealer(new HashMap<>(), weaponDatabase);
 
-    studentRepository.commit();
+    weaponRepository.commit();
 
-    verifyNoMoreInteractions(studentDatabase);
+    verifyNoMoreInteractions(weaponDatabase);
   }
 
   @Test
   void shouldNotInsertToDbIfNoRegisteredStudentsToBeCommitted() {
-    context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
+    context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
-    context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
+    context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
 
-    studentRepository.commit();
+    armsDealer.commit();
 
-    verify(studentDatabase, never()).insert(student1);
+    verify(weaponDatabase, never()).insert(weapon1);
   }
 
   @Test
   void shouldNotModifyToDbIfNotRegisteredStudentsToBeCommitted() {
-    context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
+    context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
-    context.put(UnitActions.DELETE.getActionValue(), List.of(student1));
+    context.put(UnitActions.DELETE.getActionValue(), List.of(weapon1));
 
-    studentRepository.commit();
+    armsDealer.commit();
 
-    verify(studentDatabase, never()).modify(student1);
+    verify(weaponDatabase, never()).modify(weapon1);
   }
 
   @Test
   void shouldNotDeleteFromDbIfNotRegisteredStudentsToBeCommitted() {
-    context.put(UnitActions.INSERT.getActionValue(), List.of(student1));
+    context.put(UnitActions.INSERT.getActionValue(), List.of(weapon1));
-    context.put(UnitActions.MODIFY.getActionValue(), List.of(student1));
+    context.put(UnitActions.MODIFY.getActionValue(), List.of(weapon1));
 
-    studentRepository.commit();
+    armsDealer.commit();
 
-    verify(studentDatabase, never()).delete(student1);
+    verify(weaponDatabase, never()).delete(weapon1);
   }
 }

value-object/README.md

@@ -10,19 +10,80 @@ tags:
 ---
 
 ## Intent
+
 Provide objects which follow value semantics rather than reference semantics.
-This means value objects' equality are not based on identity. Two value objects are
+This means value objects' equality is not based on identity. Two value objects are
 equal when they have the same value, not necessarily being the same object.
 
+## Explanation
+
+Real-world example
+
+> There is a class for hero statistics in a role-playing game. The statistics contain attributes
+> such as strength, intelligence, and luck. The statistics of different heroes should be equal
+> when all the attributes are equal.
+
+In plain words
+
+> Value objects are equal when their attributes have the same value
+
+Wikipedia says
+
+> In computer science, a value object is a small object that represents a simple entity whose 
+> equality is not based on identity: i.e. two value objects are equal when they have the same 
+> value, not necessarily being the same object.
+
+**Programmatic Example**
+
+Here is the `HeroStat` class that is the value object. Notice the use of 
+[Lombok's `@Value`](https://projectlombok.org/features/Value) annotation.
+
+```java
+@Value(staticConstructor = "valueOf")
+class HeroStat {
+
+    int strength;
+    int intelligence;
+    int luck;
+}
+```
+
+The example creates three different `HeroStat`s and compares their equality.
+
+```java
+var statA = HeroStat.valueOf(10, 5, 0);
+var statB = HeroStat.valueOf(10, 5, 0);
+var statC = HeroStat.valueOf(5, 1, 8);
+
+LOGGER.info(statA.toString());
+LOGGER.info(statB.toString());
+LOGGER.info(statC.toString());
+
+LOGGER.info("Is statA and statB equal : {}", statA.equals(statB));
+LOGGER.info("Is statA and statC equal : {}", statA.equals(statC));
+```
+
+Here's the console output.
+
+```
+20:11:12.199 [main] INFO com.iluwatar.value.object.App - HeroStat(strength=10, intelligence=5, luck=0)
+20:11:12.202 [main] INFO com.iluwatar.value.object.App - HeroStat(strength=10, intelligence=5, luck=0)
+20:11:12.202 [main] INFO com.iluwatar.value.object.App - HeroStat(strength=5, intelligence=1, luck=8)
+20:11:12.202 [main] INFO com.iluwatar.value.object.App - Is statA and statB equal : true
+20:11:12.203 [main] INFO com.iluwatar.value.object.App - Is statA and statC equal : false
+```
+
 ## Class diagram
+
 ![alt text](./etc/value-object.png "Value Object")
 
 ## Applicability
+
 Use the Value Object when
 
-* You need to measure the objects' equality based on the objects' value
+* The object's equality needs to be based on the object's value
 
-## Real world examples
+## Known uses
 
 * [java.util.Optional](https://docs.oracle.com/javase/8/docs/api/java/util/Optional.html)
 * [java.time.LocalDate](https://docs.oracle.com/javase/8/docs/api/java/time/LocalDate.html)
@@ -31,6 +92,7 @@ Use the Value Object when
 ## Credits
 
 * [Patterns of Enterprise Application Architecture](http://www.martinfowler.com/books/eaa.html)
+* [ValueObject](https://martinfowler.com/bliki/ValueObject.html)
 * [VALJOs - Value Java Objects : Stephen Colebourne's blog](http://blog.joda.org/2014/03/valjos-value-java-objects.html)
 * [Value Object : Wikipedia](https://en.wikipedia.org/wiki/Value_object)
 * [J2EE Design Patterns](https://www.amazon.com/gp/product/0596004273/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0596004273&linkCode=as2&tag=javadesignpat-20&linkId=f27d2644fbe5026ea448791a8ad09c94)

value-object/src/main/java/com/iluwatar/value/object/App.java

@@ -43,7 +43,7 @@ import lombok.extern.slf4j.Slf4j;
 public class App {
 
   /**
-   * This practice creates three HeroStats(Value object) and checks equality between those.
+   * This example creates three HeroStats (value objects) and checks equality between those.
    */
   public static void main(String[] args) {
     var statA = HeroStat.valueOf(10, 5, 0);
@@ -51,6 +51,8 @@ public class App {
     var statC = HeroStat.valueOf(5, 1, 8);
 
     LOGGER.info(statA.toString());
+    LOGGER.info(statB.toString());
+    LOGGER.info(statC.toString());
 
     LOGGER.info("Is statA and statB equal : {}", statA.equals(statB));
     LOGGER.info("Is statA and statC equal : {}", statA.equals(statC));

value-object/src/main/java/com/iluwatar/value/object/HeroStat.java

@@ -23,10 +23,7 @@
 
 package com.iluwatar.value.object;
 
-import lombok.EqualsAndHashCode;
+import lombok.Value;
-import lombok.Getter;
-import lombok.RequiredArgsConstructor;
-import lombok.ToString;
 
 /**
  * HeroStat is a value object.
@@ -35,23 +32,10 @@ import lombok.ToString;
  *     http://docs.oracle.com/javase/8/docs/api/java/lang/doc-files/ValueBased.html
  *     </a>
  */
-@Getter
+@Value(staticConstructor = "valueOf")
-@ToString
+class HeroStat {
-@EqualsAndHashCode
-@RequiredArgsConstructor
-public class HeroStat {
-
-  // Stats for a hero
-
-  private final int strength;
-  private final int intelligence;
-  private final int luck;
-
-  // Static factory method to create new instances.
-  public static HeroStat valueOf(int strength, int intelligence, int luck) {
-    return new HeroStat(strength, intelligence, luck);
-  }
-
-  // The clone() method should not be public. Just don't override it.
 
+  int strength;
+  int intelligence;
+  int luck;
 }