Merge pull request #93 from lhy-hoyin/branch-SortEvent

New Feature: ShowNext Command
and code for upcoming event (not fully implemented yet)

src/main/java/ezschedule/logic/Logic.java

@@ -33,6 +33,11 @@ public interface Logic {
      */
     ReadOnlyScheduler getScheduler();
 
+    /**
+     * Returns an unmodifiable view of the upcoming list of events
+     */
+    ObservableList<Event> getUpcomingEventList();
+
     /**
      * Returns an unmodifiable view of the list of events
      */

src/main/java/ezschedule/logic/LogicManager.java

@@ -60,6 +60,11 @@ public ReadOnlyScheduler getScheduler() {
         return model.getScheduler();
     }
 
+    @Override
+    public ObservableList<Event> getUpcomingEventList() {
+        return model.getUpcomingEventList();
+    }
+
     @Override
     public ObservableList<Event> getEventList() {
         return model.getEventList();

src/main/java/ezschedule/logic/commands/ShowNextCommand.java

@@ -0,0 +1,43 @@
+package ezschedule.logic.commands;
+
+import static java.util.Objects.requireNonNull;
+
+import ezschedule.commons.core.Messages;
+import ezschedule.logic.commands.exceptions.CommandException;
+import ezschedule.model.Model;
+import ezschedule.model.event.UpcomingEventPredicate;
+
+/**
+ * List the next (or next few) upcoming events.
+ * Completed events are not considered upcoming.
+ */
+public class ShowNextCommand extends Command {
+
+    public static final String COMMAND_WORD = "next";
+
+    public static final String MESSAGE_USAGE = COMMAND_WORD + ": Display upcoming events."
+            + "\nCan be used without any parameters."
+            + "\nParameter: COUNT (must be a positive integer)"
+            + "\nExample: " + COMMAND_WORD + " 3";
+
+    private final UpcomingEventPredicate predicate;
+
+    public ShowNextCommand(UpcomingEventPredicate predicate) {
+        this.predicate = predicate;
+    }
+
+    @Override
+    public CommandResult execute(Model model) throws CommandException {
+        requireNonNull(model);
+        model.updateFilteredEventList(predicate);
+        return new CommandResult(
+                String.format(Messages.MESSAGE_EVENTS_LISTED_OVERVIEW, model.getFilteredEventList().size()));
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+                || (other instanceof ShowNextCommand // instanceof handles nulls
+                && predicate.equals(((ShowNextCommand) other).predicate)); // state check
+    }
+}

src/main/java/ezschedule/logic/parser/SchedulerParser.java

@@ -14,6 +14,7 @@
 import ezschedule.logic.commands.HelpCommand;
 import ezschedule.logic.commands.ListCommand;
 import ezschedule.logic.commands.RecurCommand;
+import ezschedule.logic.commands.ShowNextCommand;
 import ezschedule.logic.parser.exceptions.ParseException;
 
 /**
@@ -61,6 +62,9 @@ public Command parseCommand(String userInput) throws ParseException {
         case ListCommand.COMMAND_WORD:
             return new ListCommand();
 
+        case ShowNextCommand.COMMAND_WORD:
+            return new ShowNextCommandParser().parse(arguments);
+
         case ExitCommand.COMMAND_WORD:
             return new ExitCommand();
 

src/main/java/ezschedule/logic/parser/ShowNextCommandParser.java

@@ -0,0 +1,38 @@
+package ezschedule.logic.parser;
+
+import ezschedule.commons.core.Messages;
+import ezschedule.logic.commands.ShowNextCommand;
+import ezschedule.logic.parser.exceptions.ParseException;
+import ezschedule.model.event.UpcomingEventPredicate;
+
+/**
+ * Parses input arguments and creates a new ShowNextCommandParser object
+ */
+public class ShowNextCommandParser implements Parser<ShowNextCommand> {
+
+    /**
+     * Parses the given {@code String} of arguments in the context of the ShowNextCommand
+     * and returns an ShowNextCommand object for execution.
+     *
+     * @throws ParseException if the user input does not conform the expected format
+     */
+    @Override
+    public ShowNextCommand parse(String userInput) throws ParseException {
+        // No argument provided, just show the next one
+        if (userInput.isBlank()) {
+            return new ShowNextCommand(new UpcomingEventPredicate(1));
+        }
+
+        try {
+            int count = Integer.parseInt(userInput.trim());
+            if (count > 0) {
+                return new ShowNextCommand(new UpcomingEventPredicate(count));
+            }
+        } catch (NumberFormatException e) {
+            // Empty here; another exception is throw outside.
+        }
+
+        throw new ParseException(
+                String.format(Messages.MESSAGE_INVALID_COMMAND_FORMAT, ShowNextCommand.MESSAGE_USAGE));
+    }
+}

src/main/java/ezschedule/model/Model.java

@@ -85,11 +85,17 @@ public interface Model {
      */
     void setEvent(Event target, Event editedEvent);
 
+    /**
+     * Returns an unmodifiable view of the upcoming event list
+     */
+    ObservableList<Event> getUpcomingEventList();
+
     /**
      * Returns an unmodifiable view of the event list
      */
     ObservableList<Event> getEventList();
 
+
     /**
      * Returns an unmodifiable view of the filtered event list
      */

src/main/java/ezschedule/model/ModelManager.java

@@ -24,7 +24,7 @@ public class ModelManager implements Model {
     private final FilteredList<Event> filteredEvents;
 
     /**
-     * Initializes a ModelManager with the given addressBook and userPrefs.
+     * Initializes a ModelManager with the given scheduler and userPrefs.
      */
     public ModelManager(ReadOnlyScheduler scheduler, ReadOnlyUserPrefs userPrefs) {
         requireAllNonNull(scheduler, userPrefs);
@@ -120,7 +120,16 @@ public void setEvent(Event target, Event editedEvent) {
 
     /**
      * Returns an unmodifiable view of the list of {@code Event} backed by the internal list of
-     * {@code versionedScheduler}
+     * {@code scheduler}
+     */
+    @Override
+    public ObservableList<Event> getUpcomingEventList() {
+        return scheduler.getUpcomingEvents();
+    }
+
+    /**
+     * Returns an unmodifiable view of the list of {@code Event} backed by the internal list of
+     * {@code scheduler}
      */
     @Override
     public ObservableList<Event> getEventList() {

src/main/java/ezschedule/model/Scheduler.java

@@ -6,16 +6,22 @@
 
 import ezschedule.model.event.Event;
 import ezschedule.model.event.UniqueEventList;
+import ezschedule.model.event.UpcomingEventPredicate;
 import javafx.collections.ObservableList;
+import javafx.collections.transformation.FilteredList;
 
 /**
  * Wraps all data at the scheduler level
  * Duplicates are not allowed (by .isSameEvent comparison)
  */
 public class Scheduler implements ReadOnlyScheduler {
+    private static final int DISPLAY_UPCOMING_COUNT = 1;
+    private static final UpcomingEventPredicate predicate = new UpcomingEventPredicate(DISPLAY_UPCOMING_COUNT);
 
     private final UniqueEventList events;
 
+    private FilteredList<Event> upcomingEvents;
+
     /*
      * The 'unusual' code block below is a non-static initialization block, sometimes used to avoid duplication
      * between constructors. See https://docs.oracle.com/javase/tutorial/java/javaOO/initial.html
@@ -27,7 +33,28 @@ public class Scheduler implements ReadOnlyScheduler {
         events = new UniqueEventList();
     }
 
-    public Scheduler() {}
+    /**
+     * Construct an instance of Scheduler object.
+     * Listeners are attached in here.
+     */
+    public Scheduler() {
+        upcomingEvents = new FilteredList<>(getEventList());
+
+        // Attach a listener to auto-sort events in chronological order
+        events.addListChangeListener(c -> {
+            while (c.next()) {
+                if (!c.wasPermutated()) {
+                    events.sortByChronologicalOrder();
+                }
+            }
+        });
+
+        events.addListChangeListener(c -> {
+            while (c.next()) { /* Do nothing */ }
+            upcomingEvents.setPredicate(predicate);
+        });
+
+    }
 
     /**
      * Creates a Scheduler using the Events in the {@code toBeCopied}
@@ -99,6 +126,15 @@ public void removeEvent(Event key) {
         events.remove(key);
     }
 
+    /**
+     * Returns the list of upcoming {@code Event}
+     *
+     * @return
+     */
+    public FilteredList<Event> getUpcomingEvents() {
+        return upcomingEvents;
+    }
+
     //// util methods
 
     @Override

src/main/java/ezschedule/model/event/Event.java

@@ -38,13 +38,24 @@ public Time getEndTime() {
     }
 
     public String getCompletedStatus() {
-        return date.isPastDate()
-                ? "Event completed"
-                : date.isFutureDate()
-                ? ""
-                : endTime.isPastTime()
-                ? "Event completed"
-                : "";
+        return isCompleted() ? "Event completed" : "";
+    }
+
+    /**
+     * Returns true if the event has been completed/is over.
+     *
+     * @return true if event is completed.
+     */
+    public boolean isCompleted() {
+        if (date.isPastDate()) {
+            return true; // Event is before today
+        } else if (date.isFutureDate()) {
+            return false; // Event is after today
+        } else {
+            // Event is sometime today
+            // Is current time passed the event end time?
+            return endTime.isPastTime();
+        }
     }
 
     /**

src/main/java/ezschedule/model/event/EventContainsKeywordsPredicate.java

@@ -6,7 +6,7 @@
 import ezschedule.commons.util.StringUtil;
 
 /**
- * Tests that a {@code Event}'s {@code Name} matches any of the keywords given.
+ * Tests that an {@code Event}'s {@code Name} matches any of the keywords given.
  */
 public class EventContainsKeywordsPredicate implements Predicate<Event> {
 

src/main/java/ezschedule/model/event/UniqueEventList.java

@@ -30,21 +30,6 @@ public class UniqueEventList implements Iterable<Event> {
     private final ObservableList<Event> internalUnmodifiableList =
             FXCollections.unmodifiableObservableList(internalList);
 
-    /**
-     * Constructor of UniqueEventList.
-     * Attaches a listener to sort the list of events in chronological order whenever its changed.
-     */
-    public UniqueEventList() {
-        // Auto-sort whenever a list is changed
-        internalList.addListener((ListChangeListener<Event>) c -> {
-            while (c.next()) {
-                if (!c.wasPermutated()) {
-                    FXCollections.sort(internalList);
-                }
-            }
-        });
-    }
-
     /**
      * Returns true if the list contains an equivalent event as the given argument.
      */
@@ -61,6 +46,22 @@ public boolean existsAtTime(Event toCheck) {
         return internalList.stream().anyMatch(toCheck::isEventOverlap);
     }
 
+    /**
+     * Attach {@code listener}, which is called whenever internalList is changed.
+     *
+     * @param listener A ListChangeListener to be called.
+     */
+    public void addListChangeListener(ListChangeListener<Event> listener) {
+        internalList.addListener(listener);
+    }
+
+    /**
+     * Sorts all events in chronological order.
+     */
+    public void sortByChronologicalOrder() {
+        FXCollections.sort(internalList);
+    }
+
     /**
      * Adds an event to the list.
      * The event must not already exist in the list.

src/main/java/ezschedule/model/event/UpcomingEventPredicate.java

@@ -0,0 +1,33 @@
+package ezschedule.model.event;
+
+import java.util.function.Predicate;
+
+/**
+ * Tests that an {@code Event} is one of the upcoming events.
+ * Only the first {@code count} number of upcoming events are considered.
+ */
+public class UpcomingEventPredicate implements Predicate<Event> {
+
+    private int upcomingCount;
+
+    public UpcomingEventPredicate(int count) {
+        upcomingCount = count;
+    }
+
+    // Events should be in chronological order
+    @Override
+    public boolean test(Event event) {
+        if (event.isCompleted()) {
+            return false;
+        }
+
+        return upcomingCount-- > 0;
+    }
+
+    @Override
+    public boolean equals(Object other) {
+        return other == this // short circuit if same object
+                || (other instanceof UpcomingEventPredicate // instanceof handles nulls
+                && upcomingCount == ((UpcomingEventPredicate) other).upcomingCount); // state check
+    }
+}

src/test/java/ezschedule/logic/commands/AddCommandTest.java

@@ -143,6 +143,11 @@ public void setEvent(Event target, Event editedEvent) {
             throw new AssertionError("This method should not be called.");
         }
 
+        @Override
+        public ObservableList<Event> getUpcomingEventList() {
+            throw new AssertionError("This method should not be called.");
+        }
+
         @Override
         public ObservableList<Event> getEventList() {
             throw new AssertionError("This method should not be called.");

src/test/java/ezschedule/logic/parser/SchedulerParserTest.java

@@ -19,6 +19,7 @@
 import ezschedule.logic.commands.FindCommand.FindEventDescriptor;
 import ezschedule.logic.commands.HelpCommand;
 import ezschedule.logic.commands.ListCommand;
+import ezschedule.logic.commands.ShowNextCommand;
 import ezschedule.logic.parser.exceptions.ParseException;
 import ezschedule.model.event.Event;
 import ezschedule.model.event.Name;
@@ -86,6 +87,12 @@ public void parseCommand_list() throws Exception {
         assertTrue(parser.parseCommand(ListCommand.COMMAND_WORD + " 3") instanceof ListCommand);
     }
 
+    @Test
+    public void parseCommand_showNext() throws Exception {
+        assertTrue(parser.parseCommand(ShowNextCommand.COMMAND_WORD) instanceof ShowNextCommand);
+        assertTrue(parser.parseCommand(ShowNextCommand.COMMAND_WORD + " 3") instanceof ShowNextCommand);
+    }
+
     @Test
     public void parseCommand_unrecognisedInput_throwsParseException() {
         assertThrows(ParseException.class, String.format(MESSAGE_INVALID_COMMAND_FORMAT, HelpCommand.MESSAGE_USAGE), ()