EDU-2293: Update source code for "Run your first app in Java"

    * Change amount from double to int
    * Added toggles to control the success of the deposit and refund
    * Add compensation mechanism to refund failed deposit

JIRA: https://temporalio.atlassian.net/browse/EDU-2293

src/main/java/moneytransfer/AccountActivity.java

@@ -8,10 +8,10 @@
 public interface AccountActivity {
     // Withdraw an amount of money from the source account
     @ActivityMethod
-    void withdraw(String accountId, String referenceId, double amount);
+    void withdraw(String accountId, String referenceId, int amount);
 
     // Deposit an amount of money into the destination account
     @ActivityMethod
-    void deposit(String accountId, String referenceId, double amount);
+    void deposit(String accountId, String referenceId, int amount, boolean activityShouldSucceed);
 }
 // @@@SNIPEND

src/main/java/moneytransfer/AccountActivityImpl.java

@@ -1,26 +1,30 @@
 // @@@SNIPSTART money-transfer-java-activity-implementation
 package moneytransferapp;
 
+import io.temporal.activity.*;
+
 public class AccountActivityImpl implements AccountActivity {
     // Mock up the withdrawal of an amount of money from the source account
     @Override
-    public void withdraw(String accountId, String referenceId, double amount) {
+    public void withdraw(String accountId, String referenceId, int amount) {
         System.out.printf(
-                "\nWithdrawing $%.2f from account %s.\n[ReferenceId: %s]\n",
+                "\nWithdrawing $%d from account %s.\n[ReferenceId: %s]\n",
                 amount, accountId, referenceId
         );
     }
 
     // Mock up the deposit of an amount of money from the destination account
     @Override
-    public void deposit(String accountId, String referenceId, double amount) {
+    public void deposit(String accountId, String referenceId, int amount, boolean activityShouldSucceed) {
         System.out.printf(
-                "\nDepositing $%.2f into account %s.\n[ReferenceId: %s]\n",
+                "\nDepositing $%d into account %s.\n[ReferenceId: %s]\n",
                 amount, accountId, referenceId
         );
 
-        // TO SIMULATE AN ACTIVITY ERROR: Uncomment the following line
-        // throw Activity.wrap(new RuntimeException("Simulated Activity error"));
+        if (!activityShouldSucceed) {
+            System.out.println("Deposit failed");
+            throw Activity.wrap(new RuntimeException("Simulated Activity error during deposit of funds"));
+        }
     }
 }
 // @@@SNIPEND

src/main/java/moneytransfer/CoreTransactionDetails.java

@@ -5,7 +5,7 @@ public class CoreTransactionDetails implements TransactionDetails {
     private String sourceAccountId;
     private String destinationAccountId;
     private String transactionReferenceId;
-    private double amountToTransfer;
+    private int amountToTransfer;
 
     // MARK: Constructor
 
@@ -16,7 +16,8 @@ public CoreTransactionDetails() {
     public CoreTransactionDetails(String sourceAccountId,
                                   String destinationAccountId,
                                   String transactionReferenceId,
-                                  double amountToTransfer) {
+                                  int amountToTransfer)
+    {
         this.sourceAccountId = sourceAccountId;
         this.destinationAccountId = destinationAccountId;
         this.transactionReferenceId = transactionReferenceId;
@@ -37,7 +38,7 @@ public String getTransactionReferenceId() {
         return transactionReferenceId;
     }
 
-    public double getAmountToTransfer() {
+    public int getAmountToTransfer() {
         return amountToTransfer;
     }
 }

src/main/java/moneytransfer/MoneyTransferWorkflowImpl.java

@@ -45,11 +45,68 @@ public class MoneyTransferWorkflowImpl implements MoneyTransferWorkflow {
     // other Activity methods.
     @Override
     public void transfer(TransactionDetails transaction) {
-        System.out.println("Starting");
-        accountActivityStub.withdraw(transaction.getSourceAccountId(), transaction.getTransactionReferenceId(), transaction.getAmountToTransfer());
-        System.out.println("Working");
-        accountActivityStub.deposit(transaction.getDestinationAccountId(), transaction.getTransactionReferenceId(), transaction.getAmountToTransfer());
-        System.out.println("Done");
+        String sourceAccountId = transaction.getSourceAccountId();
+        String destinationAccountId = transaction.getDestinationAccountId();
+        String transactionReferenceId = transaction.getTransactionReferenceId();
+        int amountToTransfer = transaction.getAmountToTransfer();
+
+        try {
+            accountActivityStub.withdraw(sourceAccountId, transactionReferenceId, amountToTransfer);
+        } catch (Exception e) {
+            // If the withdrawal fails, for any exception
+            System.out.printf("[%s] Withdrawal of $%d from account %s failed",
+                transactionReferenceId, amountToTransfer, sourceAccountId);
+            System.out.flush();
+
+            // Transaction ends here
+            return;
+        }
+
+        // Change this from true to false to force the deposit to fail
+        boolean transferShouldSucceed = true;
+
+        try {
+            accountActivityStub.deposit(destinationAccountId, transactionReferenceId, amountToTransfer, transferShouldSucceed);
+
+            // Successful. Transaction ends here
+            System.out.printf("[%s] Transaction succeeded.\n", transactionReferenceId);
+            System.out.flush();
+            return;
+        } catch (Exception e) {
+            // If the deposit fails, for any exception
+            System.out.printf("[%s] Deposit of $%d to account %s failed.\n",
+                transactionReferenceId, amountToTransfer, destinationAccountId);
+            System.out.flush();
+        }
+
+        // Continue by reversing transaction
+
+        // Change this from true to false to force the recovery compensation to fail
+        boolean refundShouldSucceed = true;
+
+        try {
+            // Refund the withdrawal
+            System.out.printf("[%s] Refunding $%d to account %s.\n",
+                transactionReferenceId, amountToTransfer, destinationAccountId);
+            System.out.flush();
+            accountActivityStub.deposit(sourceAccountId, transactionReferenceId, amountToTransfer, refundShouldSucceed);
+
+            // Recovery successful. Transaction ends here
+            System.out.printf("[%s] Refund to originating account was successful.\n",
+                transactionReferenceId);
+            System.out.printf("[%s] Transaction is complete. No transfer made.\n",
+                transactionReferenceId);
+            return;
+        } catch (Exception e) {
+            // A recovery mechanism can fail too. Handle any exception
+            System.out.printf("[%s] Deposit of $%d to account %s failed. Did not compensate withdrawal.\n",
+                transactionReferenceId, amountToTransfer, destinationAccountId);
+            System.out.flush();
+        }
+
+        System.out.printf("[%s] Ended transaction in inconsistent state.\n",
+            transactionReferenceId);
+        System.out.flush();
     }
 }
 // @@@SNIPEND

src/main/java/moneytransfer/TransactionDetails.java

@@ -7,7 +7,7 @@ public interface TransactionDetails {
     String getSourceAccountId();
     String getDestinationAccountId();
     String getTransactionReferenceId();
-    double getAmountToTransfer();
+    int getAmountToTransfer();
 }
 // @@@SNIPEND
 

src/main/java/moneytransfer/TransferApp.java

@@ -24,7 +24,7 @@ public class TransferApp {
     }
 
     public static String randomAccountIdentifier() {
-        return IntStream.range(0, 11)
+        return IntStream.range(0, 9)
                 .mapToObj(i -> String.valueOf(random.nextInt(10)))
                 .collect(Collectors.joining());
     }
@@ -56,15 +56,15 @@ public static void main(String[] args) throws Exception {
         String referenceId = UUID.randomUUID().toString().substring(0, 18);
         String fromAccount = randomAccountIdentifier();
         String toAccount = randomAccountIdentifier();
-        double amountToTransfer = ThreadLocalRandom.current().nextDouble(15.0, 25.0);
+        int amountToTransfer = ThreadLocalRandom.current().nextInt(15, 75);
         TransactionDetails transaction = new CoreTransactionDetails(fromAccount, toAccount, referenceId, amountToTransfer);
 
         // Perform asynchronous execution.
         // This process exits after making this call and printing details.
         WorkflowExecution we = WorkflowClient.start(workflow::transfer, transaction);
 
         System.out.printf("\nMONEY TRANSFER PROJECT\n\n");
-        System.out.printf("Initiating transfer of $%.2f from [Account %s] to [Account %s].\n\n",
+        System.out.printf("Initiating transfer of $%d from [Account %s] to [Account %s].\n\n",
                           amountToTransfer, fromAccount, toAccount);
         System.out.printf("[WorkflowID: %s]\n[RunID: %s]\n\n", we.getWorkflowId(), we.getRunId());
         System.exit(0);

src/test/java/moneytransfer/MoneyTransferWorkflowTest.java

@@ -42,10 +42,10 @@ public void testTransfer() {
                 .setTaskQueue(Shared.MONEY_TRANSFER_TASK_QUEUE)
                 .build();
         MoneyTransferWorkflow workflow = workflowClient.newWorkflowStub(MoneyTransferWorkflow.class, options);
-        TransactionDetails transaction = new CoreTransactionDetails("account1", "account2", "reference1", 1.23);
+        TransactionDetails transaction = new CoreTransactionDetails("account1", "account2", "reference1", 10);
         workflow.transfer(transaction);
-        verify(activities).withdraw(eq("account1"), eq("reference1"), eq(1.23));
-        verify(activities).deposit(eq("account2"), eq("reference1"), eq(1.23));
+        verify(activities).withdraw(eq("account1"), eq("reference1"), eq(10));
+        // Cannot reliably test deposit as the failure configurations will affect this
     }
 }
 // @@@SNIPEND