update developerguide and add assertions to transactionlist class

data/carData.txt

@@ -0,0 +1 @@
+Honda Civic | SZZ1579D | 150.0 | true

data/transactionData.txt

@@ -0,0 +1 @@
+SZZ1579D | Apple | -1 | 11-12-2025

docs/DeveloperGuide.md

@@ -117,6 +117,47 @@ Responsibility principle (SRP) or Separation of Concerns principle (SOC).
     - Possibility that user might forget to update rental status
     - Need to add new commands to update rental status (e.g. `mark-rented`) 
 
+### Implementation of Transaction Completion Management and Retrieval Features
+
+To enhance the functionality of **CliRental**, we have implemented features that allow users to mark transactions as completed or uncompleted, list transactions based on their completion status, and find transactions by customer name. These features streamline the process of managing rental transactions, ensuring accurate tracking and easy retrieval of relevant data.
+
+#### **1. Overview of Features**
+
+- **Marking/Unmarking Transactions as Completed:**
+  - **Mark Completed:** Allows users to mark a specific transaction as completed, indicating that the rental process has been finalized.
+  - **Unmark Completed:** Enables users to revert a transaction's status from completed to uncompleted if needed.
+
+- **Listing Transactions:**
+  - **List Completed Transactions:** Displays all transactions that have been marked as completed.
+  - **List Uncompleted Transactions:** Shows all transactions that are still pending completion.
+
+- **Finding Transactions by Customer Name:**
+  - Facilitates the retrieval of all transactions associated with a specific customer, enabling efficient management and review.
+
+#### **2. Design & Implementation**
+
+The implementation of these features is encapsulated within the `TransactionList` class, which manages all transaction-related operations. Below is a detailed breakdown of the design and implementation strategies employed.
+
+##### **a. Class-Level Design**
+
+**`TransactionList` Class:**
+
+- **Responsibilities:**
+  - Manage the list of all transactions.
+  - Provide functionalities to add, remove, update, and retrieve transactions based on various criteria.
+
+- **Key Methods:**
+  - `markCompletedByTxId(String txId)`: Marks a transaction as completed.
+  - `unmarkCompletedByTxId(String txId)`: Marks a transaction as uncompleted.
+  - `printCompletedTransactions()`: Lists all completed transactions.
+  - `printUncompletedTransactions()`: Lists all uncompleted transactions.
+  - `findTxsByCustomer(String customer)`: Retrieves transactions associated with a specific customer.
+
+**Design Considerations:**
+
+- **Encapsulation:** The `transactionList` is maintained as a private static `ArrayList<Transaction>`, ensuring controlled access through public methods.
+- **Data Integrity:** Assertions and exception handling are employed to maintain the integrity of transaction data during operations.
+
 ## Product scope
 ### Target user profile
 

docs/UserGuide.md

@@ -89,6 +89,44 @@ What would you like to do?
 ____________________________________________________________
 ```
 
+### Adding a Transaction: `add-tx`
+
+Adds a new rental transaction to the system.
+
+**Format:** `add-transaction /tx [LICENSE_PLATE] /u [USERNAME] /d [DURATION_DAYS] /s [START_DATE]`
+
+- **`/tx`**: License plate number of the car (format: `SXX####X`).
+- **`/u`**: Username of the customer.
+- **`/d`**: Rental duration in days.
+- **`/s`**: Rental start date (format: `YYYY-MM-DD`).
+- **Parameters must be in the specified sequence.**
+
+**Example:** add-tx /p SZZ1579D /u John /d 15 /s 11-5-2025
+Sample Response:
+```
+Transaction added: 
+[ ] TX2 | SZZ1579D | John | 15day(s) 
+Start Date: 2025-05-11
+____________________________________________________________
+```
+
+
+### Listing All Transactions: `list-tx`
+
+Displays all rental transactions in the system.
+
+**Format:** `list-tx`
+
+**Sample Response:**
+```
+Here are all the transactions: 
+1) [ ] TX1 | SZZ1579D | Apple | 1day(s) 
+Start Date: 2025-12-11
+2) [ ] TX2 | SZZ1579D | John | 15day(s) 
+Start Date: 2025-05-11
+____________________________________________________________```
+```
+
 ## FAQ
 
 **Q**: Is there any file saving system in place currently? 

src/main/java/transaction/TransactionList.java

@@ -7,10 +7,16 @@
 
 public class TransactionList {
 
+    // Ensure the transaction list is initialized properly
     private static final ArrayList<Transaction> transactionList = new ArrayList<>();
 
     public static void addTx(Transaction transaction) {
+        // Assert that the transaction is not null
+        assert transaction != null : "Transaction to add should not be null.";
+
         String licensePlateNumber = transaction.getCarLicensePlate();
+        // Assert that the license plate number is not null
+        assert licensePlateNumber != null : "License plate number should not be null.";
 
         if (!CarParser.isValidLicensePlateNumber(licensePlateNumber)) {
             throw CarException.invalidLicensePlateNumber();
@@ -19,14 +25,30 @@ public static void addTx(Transaction transaction) {
         if (!CarList.isExistingLicensePlateNumber(licensePlateNumber)){
             throw CarException.licensePlateNumberNotFound();
         }
+
+        // Assert that the license plate number is valid and exists before adding
+        assert CarParser.isValidLicensePlateNumber(licensePlateNumber)
+                && CarList.isExistingLicensePlateNumber(licensePlateNumber)
+                : "License plate number must be valid and exist in CarList.";
+
         transactionList.add(transaction);
+
+        // Assert that the transaction was added successfully
+        assert transactionList.contains(transaction) : "Transaction was not added to the list.";
+
         CarList.markCarAsRented(licensePlateNumber);
         System.out.println("Transaction added: ");
         System.out.println(transaction);
     }
 
     public static void addTxWithoutPrintingInfo(Transaction transaction) {
+        // Assert that the transaction is not null
+        assert transaction != null : "Transaction to add should not be null.";
+
         transactionList.add(transaction);
+
+        // Assert that the transaction was added successfully
+        assert transactionList.contains(transaction) : "Transaction was not added to the list.";
     }
 
     public static void printAllTransactions() {
@@ -40,6 +62,8 @@ public static void printAllTransactions() {
         System.out.println("Here are all the transactions: ");
 
         for (Transaction transaction : transactionList) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
             System.out.println(index + ") " + transaction);
             index++;
         }
@@ -56,6 +80,8 @@ public static void printCompletedTransactions() {
         System.out.println("Here are all the completed transactions: ");
 
         for (Transaction transaction : transactionList) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
             if(transaction.isCompleted()) {
                 System.out.println(index + ") " + transaction);
                 index++;
@@ -74,6 +100,8 @@ public static void printUncompletedTransactions() {
         System.out.println("Here are all the uncompleted transactions: ");
 
         for (Transaction transaction : transactionList) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
             if(!transaction.isCompleted()) {
                 System.out.println(index + ") " + transaction);
                 index++;
@@ -82,21 +110,34 @@ public static void printUncompletedTransactions() {
     }
 
     public static void removeTxByTxId(String txId) {
+        // Assert that txId is not null
+        assert txId != null : "Transaction ID to remove should not be null.";
+
         for (Transaction transaction : transactionList) {
-            if (transaction.getTransactionId().toLowerCase().equals(txId)) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
+            if (transaction.getTransactionId().equalsIgnoreCase(txId)) {
                 System.out.println("Transaction deleted: " + transaction);
                 transactionList.remove(transaction);
+
+                // Assert that the transaction was removed successfully
+                assert !transactionList.contains(transaction) : "Transaction was not removed from the list.";
                 return;
             }
         }
         System.out.println("Transaction not found");
     }
 
     public static void findTxsByCustomer(String customer) {
+        // Assert that customer is not null
+        assert customer != null : "Customer name to find transactions should not be null.";
+
         boolean found = false;
         System.out.println("Transaction(s) by " + customer + " found:");
         for (Transaction transaction : transactionList) {
-            if (transaction.getCustomer().toLowerCase().equals(customer)) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
+            if (transaction.getCustomer().toLowerCase().contains(customer)) {
                 found = true;
                 System.out.println(transaction);
             }
@@ -107,30 +148,49 @@ public static void findTxsByCustomer(String customer) {
     }
 
     public static void markCompletedByTxId(String txId) {
+        // Assert that txId is not null
+        assert txId != null : "Transaction ID to mark as completed should not be null.";
+
         for (Transaction transaction : transactionList) {
-            if (transaction.getTransactionId().toLowerCase().equals(txId)) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
+            if (transaction.getTransactionId().equalsIgnoreCase(txId)) {
                 transaction.setCompleted(true);
                 System.out.println("Transaction completed: " + transaction);
+
+                // Assert that the transaction is marked as completed
+                assert transaction.isCompleted() : "Transaction was not marked as completed.";
                 return;
             }
         }
         System.out.println("Transaction not found");
     }
 
     public static void unmarkCompletedByTxId(String txId) {
+        // Assert that txId is not null
+        assert txId != null : "Transaction ID to unmark as completed should not be null.";
+
         for (Transaction transaction : transactionList) {
-            if (transaction.getTransactionId().toLowerCase().equals(txId)) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
+            if (transaction.getTransactionId().equalsIgnoreCase(txId)) {
                 transaction.setCompleted(false);
                 System.out.println("Transaction set uncompleted: " + transaction);
+
+                // Assert that the transaction is marked as uncompleted
+                assert !transaction.isCompleted() : "Transaction was not unmarked as completed.";
                 return;
             }
         }
         System.out.println("Transaction not found");
     }
 
     public static String transactionListToFileString(){
+
         StringBuilder transactionData = new StringBuilder();
         for (Transaction transaction : transactionList) {
+            // Assert that each transaction is not null
+            assert transaction != null : "Transaction in the list should not be null.";
             transactionData.append(transaction.toFileString());
             transactionData.append(System.lineSeparator());
         }