Add ability to sort the transactions in ascending order of the transa…

…ction dates

src/main/java/seedu/duke/command/ListAndStatsCommand.java

@@ -24,6 +24,7 @@ public abstract class ListAndStatsCommand extends Command {
     public static final int CONTAIN_EITHER = 2;
     public static final int CONTAIN_EITHER_INVALID = 3;
     private static final int FALSE = 0;
+    private static final String DAYS = "days";
     private static final String WEEKS = "weeks";
     private static final String MONTHS = "months";
     private static Logger listStatsLogger = Logger.getLogger(ListAndStatsCommand.class.getName());
@@ -142,8 +143,12 @@ public ArrayList<Transaction> getTimeTransactions(TransactionList transactions)
             timeTransactions = transactions.getTransactionsByMonthRange(LocalDate.now(), number);
         } else if (containPeriodNumber() == CONTAIN_BOTH && period == WEEKS) {
             timeTransactions = transactions.getTransactionsByWeekRange(LocalDate.now(), number);
+        } else if (containPeriodNumber() == CONTAIN_BOTH && period == DAYS) {
+            timeTransactions = transactions.getTransactionsByDayRange(LocalDate.now(), number);
         }
 
+        // Sorts time-filtered transactions array list based on ascending order of date
+        Collections.sort(timeTransactions);
         return timeTransactions;
     }
 }

src/main/java/seedu/duke/data/transaction/Transaction.java

@@ -9,7 +9,7 @@
 /**
  * Represents a transaction made by the user, which could be either an income or an expense.
  */
-public abstract class Transaction {
+public abstract class Transaction implements Comparable<Transaction> {
     //@@author chydarren
     private static final String PREFIX_CATEGORY = "[";
     private static final String POSTFIX_CATEGORY = "]";
@@ -68,6 +68,19 @@ public void setDate(LocalDate date) {
         this.date = date;
     }
 
+    //@@author chydarren
+
+    /**
+     * A comparator between dates of two transaction objects to facilitate sorting by date.
+     *
+     * @param transaction The transaction object.
+     * @return An integer that informs the order of comparison between two objects of same type.
+     */
+    @Override
+    public int compareTo(Transaction transaction) {
+        return getDate().compareTo(transaction.getDate());
+    }
+
     //@@author wcwy
 
     /**