Java 11 migrate remaining e (#1112)

* Moves eip-aggregator to Java 11

* Moves eip-message-channel to Java 11

* Moves eip-publish-subscribe to Java 11

* Moves eip-splitter to Java 11

* Moves eip-wire-tap to Java 11

* Moves event-aggregator to Java 11

* Moves event-asynchronous to Java 11

* Moves event-driven-architecture to Java 11

* Moves event-queue to Java 11

* Moves event-sourcing to Java 11

* Moves execute-around to Java 11

* Moves extension-objects to Java 11

event-sourcing/src/main/java/com/iluwatar/event/sourcing/app/App.java

@@ -69,7 +69,7 @@ public class App {
    */
   public static void main(String[] args) {
 
-    DomainEventProcessor eventProcessor = new DomainEventProcessor();
+    var eventProcessor = new DomainEventProcessor();
 
 
     LOGGER.info("Running the system first time............");

event-sourcing/src/main/java/com/iluwatar/event/sourcing/domain/Account.java

@@ -104,7 +104,7 @@ public class Account {
    * @return the account
    */
   public Account copy() {
-    Account account = new Account(accountNo, owner);
+    var account = new Account(accountNo, owner);
     account.setMoney(money);
     return account;
   }
@@ -135,7 +135,7 @@ public class Account {
   }
 
   private void handleWithdrawal(BigDecimal money, boolean realTime) {
-    if (this.money.compareTo(money) == -1) {
+    if (this.money.compareTo(money) < 0) {
       throw new RuntimeException("Insufficient Account Balance");
     }
 

event-sourcing/src/main/java/com/iluwatar/event/sourcing/event/AccountCreateEvent.java

@@ -72,7 +72,7 @@ public class AccountCreateEvent extends DomainEvent {
 
   @Override
   public void process() {
-    Account account = AccountAggregate.getAccount(accountNo);
+    var account = AccountAggregate.getAccount(accountNo);
     if (account != null) {
       throw new RuntimeException("Account already exists");
     }

event-sourcing/src/main/java/com/iluwatar/event/sourcing/event/MoneyDepositEvent.java

@@ -23,9 +23,9 @@
 
 package com.iluwatar.event.sourcing.event;
 
-import com.iluwatar.event.sourcing.domain.Account;
 import com.iluwatar.event.sourcing.state.AccountAggregate;
 import java.math.BigDecimal;
+import java.util.Optional;
 
 /**
  * This is the class that implements money deposit event. Holds the necessary info for a money
@@ -73,10 +73,8 @@ public class MoneyDepositEvent extends DomainEvent {
 
   @Override
   public void process() {
-    Account account = AccountAggregate.getAccount(accountNo);
-    if (account == null) {
-      throw new RuntimeException("Account not found");
-    }
+    var account = Optional.ofNullable(AccountAggregate.getAccount(accountNo))
+        .orElseThrow(() -> new RuntimeException("Account not found"));
     account.handleEvent(this);
   }
 }

event-sourcing/src/main/java/com/iluwatar/event/sourcing/event/MoneyTransferEvent.java

@@ -23,9 +23,9 @@
 
 package com.iluwatar.event.sourcing.event;
 
-import com.iluwatar.event.sourcing.domain.Account;
 import com.iluwatar.event.sourcing.state.AccountAggregate;
 import java.math.BigDecimal;
+import java.util.Optional;
 
 /**
  * This is the class that implements money transfer event. Holds the necessary info for a money
@@ -86,15 +86,10 @@ public class MoneyTransferEvent extends DomainEvent {
 
   @Override
   public void process() {
-    Account accountFrom = AccountAggregate.getAccount(accountNoFrom);
-    if (accountFrom == null) {
-      throw new RuntimeException("Account not found " + accountNoFrom);
-    }
-    Account accountTo = AccountAggregate.getAccount(accountNoTo);
-    if (accountTo == null) {
-      throw new RuntimeException("Account not found " + accountNoTo);
-    }
-
+    var accountFrom = Optional.ofNullable(AccountAggregate.getAccount(accountNoFrom))
+        .orElseThrow(() -> new RuntimeException("Account not found " + accountNoFrom));
+    var accountTo = Optional.ofNullable(AccountAggregate.getAccount(accountNoTo))
+        .orElseThrow(() -> new RuntimeException("Account not found " + accountNoTo));
     accountFrom.handleTransferFromEvent(this);
     accountTo.handleTransferToEvent(this);
   }

event-sourcing/src/main/java/com/iluwatar/event/sourcing/processor/DomainEventProcessor.java

@@ -57,13 +57,8 @@ public class DomainEventProcessor {
    */
   public void recover() {
     DomainEvent domainEvent;
-    while (true) {
-      domainEvent = processorJournal.readNext();
-      if (domainEvent == null) {
-        break;
-      } else {
-        domainEvent.process();
-      }
+    while ((domainEvent = processorJournal.readNext()) != null) {
+      domainEvent.process();
     }
   }
 }

event-sourcing/src/main/java/com/iluwatar/event/sourcing/processor/JsonFileJournal.java

@@ -38,7 +38,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
-import java.io.Writer;
+import java.nio.charset.StandardCharsets;
 import java.util.ArrayList;
 import java.util.List;
 
@@ -60,8 +60,8 @@ public class JsonFileJournal {
   public JsonFileJournal() {
     file = new File("Journal.json");
     if (file.exists()) {
-      try (BufferedReader input = new BufferedReader(
-          new InputStreamReader(new FileInputStream(file), "UTF-8"))) {
+      try (var input = new BufferedReader(
+          new InputStreamReader(new FileInputStream(file), StandardCharsets.UTF_8))) {
         String line;
         while ((line = input.readLine()) != null) {
           events.add(line);
@@ -81,7 +81,7 @@ public class JsonFileJournal {
    * @param domainEvent the domain event
    */
   public void write(DomainEvent domainEvent) {
-    Gson gson = new Gson();
+    var gson = new Gson();
     JsonElement jsonElement;
     if (domainEvent instanceof AccountCreateEvent) {
       jsonElement = gson.toJsonTree(domainEvent, AccountCreateEvent.class);
@@ -93,9 +93,9 @@ public class JsonFileJournal {
       throw new RuntimeException("Journal Event not recegnized");
     }
 
-    try (Writer output = new BufferedWriter(
-        new OutputStreamWriter(new FileOutputStream(file, true), "UTF-8"))) {
-      String eventString = jsonElement.toString();
+    try (var output = new BufferedWriter(
+        new OutputStreamWriter(new FileOutputStream(file, true), StandardCharsets.UTF_8))) {
+      var eventString = jsonElement.toString();
       output.write(eventString + "\r\n");
     } catch (IOException e) {
       throw new RuntimeException(e);
@@ -120,13 +120,13 @@ public class JsonFileJournal {
     if (index >= events.size()) {
       return null;
     }
-    String event = events.get(index);
+    var event = events.get(index);
     index++;
 
-    JsonParser parser = new JsonParser();
-    JsonElement jsonElement = parser.parse(event);
-    String eventClassName = jsonElement.getAsJsonObject().get("eventClassName").getAsString();
-    Gson gson = new Gson();
+    var parser = new JsonParser();
+    var jsonElement = parser.parse(event);
+    var eventClassName = jsonElement.getAsJsonObject().get("eventClassName").getAsString();
+    var gson = new Gson();
     DomainEvent domainEvent;
     if (eventClassName.equals("AccountCreateEvent")) {
       domainEvent = gson.fromJson(jsonElement, AccountCreateEvent.class);

event-sourcing/src/main/java/com/iluwatar/event/sourcing/state/AccountAggregate.java

@@ -26,6 +26,7 @@ package com.iluwatar.event.sourcing.state;
 import com.iluwatar.event.sourcing.domain.Account;
 import java.util.HashMap;
 import java.util.Map;
+import java.util.Optional;
 
 /**
  * This is the static accounts map holder class. This class holds the state of the accounts.
@@ -55,11 +56,10 @@ public class AccountAggregate {
    * @return the copy of the account or null if not found
    */
   public static Account getAccount(int accountNo) {
-    Account account = accounts.get(accountNo);
-    if (account == null) {
-      return null;
-    }
-    return account.copy();
+    return Optional.of(accountNo)
+        .map(accounts::get)
+        .map(Account::copy)
+        .orElse(null);
   }
 
   /**