Merge pull request nus-cs2103-AY2021S1#78 from BILLXYR/branch-Add-Functionality-addDeleteCommandFunction

Branch add functionality add delete command function

Author: BILLXYR

src/main/java/seedu/address/logic/commands/DeleteExpenseCommand.java

@@ -0,0 +1,53 @@
+package seedu.address.logic.commands;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.List;
+
+import seedu.address.commons.core.Messages;
+import seedu.address.commons.core.index.Index;
+import seedu.address.logic.commands.exceptions.CommandException;
+import seedu.address.model.Model;
+import seedu.address.model.person.Expense;
+
+/**
+ * Deletes a person identified using it's displayed index from the address book.
+ */
+public class DeleteExpenseCommand extends Command {
+
+    public static final String COMMAND_WORD = "delete";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD
+            + ": Deletes the expense identified by the index number used in the displayed expense list.\n"
+            + "Parameters: INDEX (must be a positive integer)\n"
+            + "Example: " + COMMAND_WORD + " 1";
+
+    public static final String MESSAGE_DELETE_EXPENSE_SUCCESS = "Deleted expense: %1$s";
+
+    private final Index targetIndex;
+
+    public DeleteExpenseCommand(Index targetIndex) {
+        this.targetIndex = targetIndex;
+    }
+
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+        requireNonNull(model);
+        List<Expense> lastShownList = model.getFilteredExpenseList();
+
+        if (targetIndex.getZeroBased() >= lastShownList.size()) {
+            throw new CommandException(Messages.MESSAGE_INVALID_EXPENSE_DISPLAYED_INDEX);
+        }
+
+        Expense expenseToDelete = lastShownList.get(targetIndex.getZeroBased());
+        model.deleteExpense(expenseToDelete);
+        return new CommandResult(String.format(MESSAGE_DELETE_EXPENSE_SUCCESS, expenseToDelete));
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+                || (other instanceof DeleteExpenseCommand // instanceof handles nulls
+                && targetIndex.equals(((DeleteExpenseCommand) other).targetIndex)); // state check
+    }
+}

src/main/java/seedu/address/logic/commands/exceptions/CommandException.java

@@ -1,7 +1,7 @@
 package seedu.address.logic.commands.exceptions;
 
 /**
- * Represents an error which occurs during execution of a {@link Command}.
+ * Represents an error which occurs during execution of a command.
  */
 public class CommandException extends Exception {
     public CommandException(String message) {

src/main/java/seedu/address/logic/parser/DeleteExpenseCommandParser.java

@@ -0,0 +1,30 @@
+package seedu.address.logic.parser;
+
+import static seedu.address.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
+
+import seedu.address.commons.core.index.Index;
+import seedu.address.logic.commands.DeleteCommand;
+import seedu.address.logic.commands.DeleteExpenseCommand;
+import seedu.address.logic.parser.exceptions.ParseException;
+
+/**
+ * Parses input arguments and creates a new DeleteCommand object
+ */
+public class DeleteExpenseCommandParser implements Parser<DeleteExpenseCommand> {
+
+    /**
+     * Parses the given {@code String} of arguments in the context of the DeleteCommand
+     * and returns a DeleteCommand object for execution.
+     * @throws ParseException if the user input does not conform the expected format
+     */
+    public DeleteExpenseCommand parse(String args) throws ParseException {
+        try {
+            Index index = ParserUtil.parseIndex(args);
+            return new DeleteExpenseCommand(index);
+        } catch (ParseException pe) {
+            throw new ParseException(
+                    String.format(MESSAGE_INVALID_COMMAND_FORMAT, DeleteCommand.MESSAGE_USAGE), pe);
+        }
+    }
+
+}

src/main/java/seedu/address/logic/parser/ExpenseBookParser.java

@@ -8,6 +8,7 @@
 
 import seedu.address.logic.commands.AddExpenseCommand;
 import seedu.address.logic.commands.Command;
+import seedu.address.logic.commands.DeleteExpenseCommand;
 import seedu.address.logic.commands.DeleteDescriptionCommand;
 import seedu.address.logic.commands.DescriptionCommand;
 import seedu.address.logic.commands.ListExpenseCommand;
@@ -46,6 +47,8 @@ public Command parseCommand(String userInput) throws ParseException {
             return new DescriptionCommandParser().parse(arguments);
         case AddExpenseCommand.COMMAND_WORD:
             return new AddExpenseCommandParser().parse(arguments);
+        case DeleteExpenseCommand.COMMAND_WORD:
+            return new DeleteExpenseCommandParser().parse(arguments);
 
         case ListExpenseCommand.COMMAND_WORD:
             return new ListExpenseCommand();

src/main/java/seedu/address/model/ExpenseModelManager.java

@@ -92,16 +92,18 @@ public ReadOnlyExpenseBook getExpenseBook() {
 
     @Override
     public boolean hasExpense(Expense expense) {
-        return false;
+        requireNonNull(expense);
+        return expenseBook.hasExpense(expense);
     }
 
     @Override
     public void deleteExpense(Expense targetExpense) {
-
+        expenseBook.removeExpense(targetExpense);
     }
     @Override
     public void addExpense(Expense expense) {
-
+        expenseBook.addExpense(expense);
+        updateFilteredExpenseList(PREDICATE_SHOW_ALL_EXPENSES);
     }
 
     @Override