Add Delete Task Command

src/main/java/seedu/address/logic/commands/task/DeleteTaskCommand.java

@@ -0,0 +1,57 @@
+package seedu.address.logic.commands.task;
+
+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.CommandResult;
+import seedu.address.logic.commands.TaskCommand;
+import seedu.address.logic.commands.exceptions.CommandException;
+import seedu.address.model.Model;
+import seedu.address.model.ReadOnlyTaskList;
+import seedu.address.model.TaskList;
+import seedu.address.model.task.Task;
+
+public class DeleteTaskCommand extends TaskCommand {
+    public static final String COMMAND_WORD = "delete";
+    public static final String FULL_COMMAND_WORD = TaskCommand.COMMAND_WORD + " " + COMMAND_WORD;
+    public static final String MESSAGE_SUCCESS = "Task deleted: %1$s";
+    public static final String MESSAGE_USAGE = FULL_COMMAND_WORD
+            + ": Deletes the task identified by the index number used in the displayed task list.\n"
+            + "Parameters: INDEX (must be a positive integer)\n"
+            + "Example: " + COMMAND_WORD + " 1";
+
+    public static final String MESSAGE_DELETE_TASK_SUCCESS = "Deleted Task: %1$s";
+
+    private final Index targetIndex;
+
+    public DeleteTaskCommand(Index targetIndex) {
+        this.targetIndex = targetIndex;
+    }
+
+    /**
+     * Executes the command and returns the result message.
+     *
+     * @param model {@code Model} which the command should operate on
+     * @return feedback message of the operation result for display
+     * @throws CommandException If an error occurs during command execution.
+     */
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+        requireNonNull(model);
+
+        ReadOnlyTaskList taskList = model.getTaskList();
+
+        if (targetIndex.getZeroBased() >= taskList.getTasks().size()) {
+            throw new CommandException(Messages.MESSAGE_INVALID_TASK_DISPLAYED_INDEX);
+        }
+
+        Task deletedTask = model.getTaskAtIndex(targetIndex.getZeroBased());
+        model.deleteTask(deletedTask);
+
+        return new CommandResult(String.format(MESSAGE_DELETE_TASK_SUCCESS, deletedTask));
+
+    }
+}

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

@@ -14,7 +14,7 @@ public class DeleteCommandParser implements Parser<DeleteCommand> {
     /**
      * 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
+     * @throws ParseException if the user input does not conform to the expected format
      */
     public DeleteCommand parse(String args) throws ParseException {
         try {

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

@@ -9,11 +9,14 @@
 import seedu.address.logic.commands.HelpCommand;
 import seedu.address.logic.commands.TaskCommand;
 import seedu.address.logic.commands.task.AddTaskCommand;
+import seedu.address.logic.commands.task.DeleteTaskCommand;
 import seedu.address.logic.commands.task.DoneTaskCommand;
 import seedu.address.logic.parser.exceptions.ParseException;
 import seedu.address.logic.parser.task.AddTaskCommandParser;
+import seedu.address.logic.parser.task.DeleteTaskCommandParser;
 import seedu.address.logic.parser.task.DoneTaskCommandParser;
 
+
 /**
  * Parses all task-related commands (those starting with "task") and returns a TaskCommand.
  */
@@ -35,8 +38,13 @@ public TaskCommand parse(String userInput) throws ParseException {
         switch (commandWord) {
         case AddTaskCommand.COMMAND_WORD:
             return new AddTaskCommandParser().parse(arguments);
+
+        case DeleteTaskCommand.COMMAND_WORD:
+            return new DeleteTaskCommandParser().parse(arguments);
+
         case DoneTaskCommand.COMMAND_WORD:
             return new DoneTaskCommandParser().parse(arguments);
+
         default:
             throw new ParseException(MESSAGE_UNKNOWN_COMMAND);
         }

src/main/java/seedu/address/logic/parser/task/DeleteTaskCommandParser.java

@@ -0,0 +1,31 @@
+package seedu.address.logic.parser.task;
+
+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.task.DeleteTaskCommand;
+import seedu.address.logic.parser.Parser;
+import seedu.address.logic.parser.ParserUtil;
+import seedu.address.logic.parser.exceptions.ParseException;
+
+public class DeleteTaskCommandParser implements Parser<DeleteTaskCommand> {
+
+
+    /**
+     * Parses {@code userInput} into a new DeleteTaskCommand and returns it.
+     *
+     * @param userInput the input entered by the user
+     * @throws ParseException if {@code userInput} does not conform to the expected format
+     */
+    @Override
+    public DeleteTaskCommand parse(String userInput) throws ParseException {
+        try {
+            Index index = ParserUtil.parseIndex(userInput);
+            return new DeleteTaskCommand(index);
+        } catch (ParseException pe) {
+            throw new ParseException(
+                    String.format(MESSAGE_INVALID_COMMAND_FORMAT, DeleteCommand.MESSAGE_USAGE), pe);
+        }
+    }
+}

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

@@ -1,6 +1,7 @@
 package seedu.address.model;
 
 import java.nio.file.Path;
+import java.util.List;
 import java.util.function.Predicate;
 
 import javafx.collections.ObservableList;
@@ -86,6 +87,20 @@ public interface Model {
      */
     void updateFilteredPersonList(Predicate<Person> predicate);
 
+
+    /**
+     * Deletes the given task. The task must exist in the task list.
+     * @param deletedTask The task to delete
+     */
+    void deleteTask(Task deletedTask);
+
+    /**
+     * Returns a list of the current tasks.
+     *
+     * @return the list of tasks
+     */
+    List<Task> getTasks();
+
     /**
      * Adds the given task to the task list.
      * @param task The task to be added.
@@ -103,4 +118,5 @@ public interface Model {
      * @return Task corresponding to the index provided.
      */
     Task getTaskAtIndex(int index) throws IndexOutOfBoundsException;
+
 }

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

@@ -135,6 +135,11 @@ public void updateFilteredPersonList(Predicate<Person> predicate) {
         filteredPersons.setPredicate(predicate);
     }
 
+    @Override
+    public void deleteTask(Task deletedTask) {
+        taskList.removeTask(deletedTask);
+    }
+
     //=========== TaskMaster2103 ============================================================================
 
     @Override

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

@@ -24,6 +24,10 @@ public void addTask(Task task) {
         tasks.add(task);
     }
 
+    public void removeTask(Task deletedTask) {
+        tasks.remove(deletedTask);
+    }
+
     @Override
     public boolean equals(Object other) {
         return other == this // short circuit if same object

src/test/java/seedu/address/logic/commands/AddCommandTest.java

@@ -9,6 +9,7 @@
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.List;
 import java.util.function.Predicate;
 
 import org.junit.jupiter.api.Test;
@@ -150,6 +151,16 @@ public void updateFilteredPersonList(Predicate<Person> predicate) {
             throw new AssertionError("This method should not be called.");
         }
 
+        /**
+         * Returns a list of the current tasks.
+         *
+         * @return the list of tasks
+         */
+        @Override
+        public List<Task> getTasks() {
+            return null;
+        }
+
         @Override
         public void addTask(Task task) {
             throw new AssertionError("This method should not be called.");