Allow user to see the command history #439

docs/UserGuide.adoc

@@ -150,6 +150,11 @@ Selects the 2nd person in the address book.
 `select 1` +
 Selects the 1st person in the results of the `find` command.
 
+=== Listing entered commands : `history`
+
+Lists all the commands that you have entered in chronological order. +
+Format: `history`
+
 === Clearing all entries : `clear`
 
 Clears all entries from the address book. +
@@ -183,3 +188,4 @@ e.g. `find James Jake`
 * *Help* : `help`
 * *Select* : `select INDEX` +
 e.g.`select 2`
+* *History* : `history`

src/main/java/seedu/address/logic/CommandHistory.java

@@ -0,0 +1,32 @@
+package seedu.address.logic;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Stores the history of commands executed.
+ */
+public class CommandHistory {
+    private ArrayList<String> userInputHistory;
+
+    public CommandHistory() {
+        userInputHistory = new ArrayList<>();
+    }
+
+    /**
+     * Appends {@code userInput} to the list of user input entered.
+     */
+    public void add(String userInput) {
+        requireNonNull(userInput);
+        userInputHistory.add(userInput);
+    }
+
+    /**
+     * Returns a defensive copy of {@code userInputHistory}.
+     */
+    public List<String> getHistory() {
+        return new ArrayList<>(userInputHistory);
+    }
+}

src/main/java/seedu/address/logic/LogicManager.java

@@ -21,19 +21,25 @@ public class LogicManager extends ComponentManager implements Logic {
     private final Logger logger = LogsCenter.getLogger(LogicManager.class);
 
     private final Model model;
+    private final CommandHistory history;
     private final Parser parser;
 
     public LogicManager(Model model, Storage storage) {
         this.model = model;
+        this.history = new CommandHistory();
         this.parser = new Parser();
     }
 
     @Override
     public CommandResult execute(String commandText) throws CommandException, ParseException {
         logger.info("----------------[USER COMMAND][" + commandText + "]");
-        Command command = parser.parseCommand(commandText);
-        command.setData(model);
-        return command.execute();
+        try {
+            Command command = parser.parseCommand(commandText);
+            command.setData(model, history);
+            return command.execute();
+        } finally {
+            history.add(commandText);
+        }
     }
 
     @Override

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

@@ -1,6 +1,7 @@
 package seedu.address.logic.commands;
 
 import seedu.address.commons.core.Messages;
+import seedu.address.logic.CommandHistory;
 import seedu.address.logic.commands.exceptions.CommandException;
 import seedu.address.model.Model;
 
@@ -9,6 +10,7 @@
  */
 public abstract class Command {
     protected Model model;
+    protected CommandHistory history;
 
     /**
      * Constructs a feedback message to summarise an operation that displayed a listing of persons.
@@ -33,7 +35,7 @@ public static String getMessageForPersonListShownSummary(int displaySize) {
      * Commands making use of any of these should override this method to gain
      * access to the dependencies.
      */
-    public void setData(Model model) {
+    public void setData(Model model, CommandHistory history) {
         this.model = model;
     }
 }

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

@@ -0,0 +1,35 @@
+package seedu.address.logic.commands;
+
+import static java.util.Objects.requireNonNull;
+
+import java.util.List;
+
+import seedu.address.logic.CommandHistory;
+import seedu.address.model.Model;
+
+/**
+ * Lists all the commands entered by user from the start of app launch.
+ */
+public class HistoryCommand extends Command {
+
+    public static final String COMMAND_WORD = "history";
+    public static final String MESSAGE_SUCCESS = "Entered commands (from earliest to most recent):\n%1$s";
+    public static final String MESSAGE_NO_HISTORY = "You have not yet entered any commands.";
+
+    @Override
+    public CommandResult execute() {
+        List<String> previousCommands = history.getHistory();
+
+        if (previousCommands.isEmpty()) {
+            return new CommandResult(MESSAGE_NO_HISTORY);
+        }
+
+        return new CommandResult(String.format(MESSAGE_SUCCESS, String.join("\n", previousCommands)));
+    }
+
+    @Override
+    public void setData(Model model, CommandHistory history) {
+        requireNonNull(history);
+        this.history = history;
+    }
+}

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

@@ -14,6 +14,7 @@
 import seedu.address.logic.commands.ExitCommand;
 import seedu.address.logic.commands.FindCommand;
 import seedu.address.logic.commands.HelpCommand;
+import seedu.address.logic.commands.HistoryCommand;
 import seedu.address.logic.commands.ListCommand;
 import seedu.address.logic.commands.SelectCommand;
 import seedu.address.logic.parser.exceptions.ParseException;
@@ -66,6 +67,9 @@ public Command parseCommand(String userInput) throws ParseException {
         case ListCommand.COMMAND_WORD:
             return new ListCommand();
 
+        case HistoryCommand.COMMAND_WORD:
+            return new HistoryCommand();
+
         case ExitCommand.COMMAND_WORD:
             return new ExitCommand();
 

src/test/java/seedu/address/logic/CommandHistoryTest.java

@@ -0,0 +1,27 @@
+package seedu.address.logic;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.Arrays;
+
+import org.junit.Before;
+import org.junit.Test;
+
+public class CommandHistoryTest {
+    private CommandHistory history;
+
+    @Before
+    public void setUp() {
+        history = new CommandHistory();
+    }
+
+    @Test
+    public void add() {
+        final String validCommand = "clear";
+        final String invalidCommand = "adds Bob";
+
+        history.add(validCommand);
+        history.add(invalidCommand);
+        assertEquals(Arrays.asList(validCommand, invalidCommand), history.getHistory());
+    }
+}

src/test/java/seedu/address/logic/LogicManagerTest.java

@@ -2,6 +2,7 @@
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
 import static seedu.address.commons.core.Messages.MESSAGE_INVALID_COMMAND_FORMAT;
 import static seedu.address.commons.core.Messages.MESSAGE_INVALID_PERSON_DISPLAYED_INDEX;
 import static seedu.address.commons.core.Messages.MESSAGE_UNKNOWN_COMMAND;
@@ -41,6 +42,7 @@
 import seedu.address.logic.commands.ExitCommand;
 import seedu.address.logic.commands.FindCommand;
 import seedu.address.logic.commands.HelpCommand;
+import seedu.address.logic.commands.HistoryCommand;
 import seedu.address.logic.commands.ListCommand;
 import seedu.address.logic.commands.SelectCommand;
 import seedu.address.logic.commands.exceptions.CommandException;
@@ -432,6 +434,31 @@ public void execute_find_matchesIfAnyKeywordPresent() throws Exception {
                 expectedModel);
     }
 
+    @Test
+    public void execute_verifyHistory_success() throws Exception {
+        String validCommand = "clear";
+        logic.execute(validCommand);
+
+        String invalidCommandParse = "   adds   Bob   ";
+        try {
+            logic.execute(invalidCommandParse);
+            fail("The expected ParseException was not thrown.");
+        } catch (ParseException pe) {
+            assertEquals(MESSAGE_UNKNOWN_COMMAND, pe.getMessage());
+        }
+
+        String invalidCommandExecute = "delete 1"; // address book is of size 0; index out of bounds
+        try {
+            logic.execute(invalidCommandExecute);
+            fail("The expected CommandException was not thrown.");
+        } catch (CommandException ce) {
+            assertEquals(MESSAGE_INVALID_PERSON_DISPLAYED_INDEX, ce.getMessage());
+        }
+
+        String expectedMessage = String.format(HistoryCommand.MESSAGE_SUCCESS,
+                String.join("\n", validCommand, invalidCommandParse, invalidCommandExecute));
+        assertCommandSuccess("history", expectedMessage, model);
+    }
 
     /**
      * A utility class to generate test data.

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

@@ -14,6 +14,7 @@
 import seedu.address.commons.core.UnmodifiableObservableList;
 import seedu.address.commons.core.index.Index;
 import seedu.address.commons.exceptions.IllegalValueException;
+import seedu.address.logic.CommandHistory;
 import seedu.address.logic.commands.exceptions.CommandException;
 import seedu.address.model.Model;
 import seedu.address.model.ReadOnlyAddressBook;
@@ -61,7 +62,7 @@ public void execute_duplicatePerson_throwsCommandException() throws Exception {
      */
     private AddCommand getAddCommandForPerson(Person person, Model model) throws IllegalValueException {
         AddCommand command = new AddCommand(person);
-        command.setData(model);
+        command.setData(model, new CommandHistory());
         return command;
     }
 

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

@@ -20,6 +20,7 @@
 import seedu.address.commons.core.Messages;
 import seedu.address.commons.core.index.Index;
 import seedu.address.commons.exceptions.IllegalValueException;
+import seedu.address.logic.CommandHistory;
 import seedu.address.logic.commands.EditCommand.EditPersonDescriptor;
 import seedu.address.logic.commands.exceptions.CommandException;
 import seedu.address.model.AddressBook;
@@ -101,7 +102,7 @@ public void equals() {
      */
     private EditCommand prepareCommand(Index index, EditPersonDescriptor descriptor) {
         EditCommand editCommand = new EditCommand(index, descriptor);
-        editCommand.setData(model);
+        editCommand.setData(model, new CommandHistory());
         return editCommand;
     }
 

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

@@ -0,0 +1,49 @@
+package seedu.address.logic.commands;
+
+import static org.junit.Assert.assertEquals;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import seedu.address.logic.CommandHistory;
+import seedu.address.model.Model;
+import seedu.address.model.ModelManager;
+
+public class HistoryCommandTest {
+    private HistoryCommand historyCommand;
+    private CommandHistory history;
+
+    @Before
+    public void setUp() {
+        Model model = new ModelManager();
+        history = new CommandHistory();
+        historyCommand = new HistoryCommand();
+        historyCommand.setData(model, history);
+    }
+
+    @Test
+    public void execute() {
+        assertCommandResult(historyCommand, HistoryCommand.MESSAGE_NO_HISTORY);
+
+        String command1 = "clear";
+        history.add(command1);
+        assertCommandResult(historyCommand, String.format(HistoryCommand.MESSAGE_SUCCESS, command1));
+
+        String command2 = "randomCommand";
+        String command3 = "select 1";
+        history.add(command2);
+        history.add(command3);
+
+        String expectedMessage = String.format(HistoryCommand.MESSAGE_SUCCESS,
+                String.join("\n", command1, command2, command3));
+
+        assertCommandResult(historyCommand, expectedMessage);
+    }
+
+    /**
+     * Asserts that the result message from the execution of {@code historyCommand} equals to {@code expectedMessage}
+     */
+    private void assertCommandResult(HistoryCommand historyCommand, String expectedMessage) {
+        assertEquals(expectedMessage, historyCommand.execute().feedbackToUser);
+    }
+}

src/test/java/seedu/address/logic/parser/ParserTest.java

@@ -0,0 +1,28 @@
+package seedu.address.logic.parser;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+import static seedu.address.commons.core.Messages.MESSAGE_UNKNOWN_COMMAND;
+
+import org.junit.Test;
+
+import seedu.address.logic.commands.HistoryCommand;
+import seedu.address.logic.parser.exceptions.ParseException;
+
+public class ParserTest {
+    private final Parser parser = new Parser();
+
+    @Test
+    public void parseCommand_history() throws Exception {
+        assertTrue(parser.parseCommand(HistoryCommand.COMMAND_WORD) instanceof HistoryCommand);
+        assertTrue(parser.parseCommand(HistoryCommand.COMMAND_WORD + " 3") instanceof HistoryCommand);
+
+        try {
+            parser.parseCommand("histories");
+            fail("The expected ParseException was not thrown.");
+        } catch (ParseException pe) {
+            assertEquals(MESSAGE_UNKNOWN_COMMAND, pe.getMessage());
+        }
+    }
+}