Update ListCommand class functionality

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

@@ -1,9 +1,13 @@
 package seedu.address.logic.commands;
 
 import static java.util.Objects.requireNonNull;
-import static seedu.address.model.Model.PREDICATE_SHOW_ALL_CONTACTS;
+import static seedu.address.model.Model.PREDICATE_SHOW_ONLY_ORGANIZATIONS;
+import static seedu.address.model.Model.PREDICATE_SHOW_ONLY_RECRUITERS;
+
+import java.util.function.Predicate;
 
 import seedu.address.model.Model;
+import seedu.address.model.person.Contact;
 
 /**
  * Lists all contacts in the address book to the user.
@@ -12,13 +16,30 @@ public class ListCommand extends Command {
 
     public static final String COMMAND_WORD = "list";
 
-    public static final String MESSAGE_SUCCESS = "Listed all contacts";
+    public static final String MESSAGE_SUCCESS_ALL_CONTACTS = "Listed all contacts";
+    public static final String MESSAGE_SUCCESS_ORGANIZATIONS = "Listed all organizations";
+    public static final String MESSAGE_SUCCESS_RECRUITERS = "Listed all recruiters";
+
+    private final Predicate<Contact> predicate;
 
+    /**
+     * Creates a ListCommand listing the {@code Contact} entries of the specified type.
+     * @param predicate the predicate determining the type of {@code Contact} to be listed
+     */
+    public ListCommand(Predicate<Contact> predicate) {
+        requireNonNull(predicate);
+        this.predicate = predicate;
+    }
 
     @Override
     public CommandResult execute(Model model) {
         requireNonNull(model);
-        model.updateFilteredContactList(PREDICATE_SHOW_ALL_CONTACTS);
-        return new CommandResult(MESSAGE_SUCCESS);
+        model.updateFilteredContactList(predicate);
+        if (predicate.equals(PREDICATE_SHOW_ONLY_ORGANIZATIONS)) {
+            return new CommandResult(MESSAGE_SUCCESS_ORGANIZATIONS);
+        } else if (predicate.equals(PREDICATE_SHOW_ONLY_RECRUITERS)) {
+            return new CommandResult(MESSAGE_SUCCESS_RECRUITERS);
+        }
+        return new CommandResult(MESSAGE_SUCCESS_ALL_CONTACTS);
     }
 }

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

@@ -69,7 +69,7 @@ public Command parseCommand(String userInput) throws ParseException {
             return new FindCommandParser().parse(arguments);
 
         case ListCommand.COMMAND_WORD:
-            return new ListCommand();
+            return new ListCommandParser().parse(arguments);
 
         case ExitCommand.COMMAND_WORD:
             return new ExitCommand();

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

@@ -0,0 +1,46 @@
+package seedu.address.logic.parser;
+
+import static seedu.address.logic.parser.CliSyntax.FLAG_ORGANIZATION;
+import static seedu.address.logic.parser.CliSyntax.FLAG_RECRUITER;
+import static seedu.address.model.Model.PREDICATE_SHOW_ALL_CONTACTS;
+import static seedu.address.model.Model.PREDICATE_SHOW_ONLY_ORGANIZATIONS;
+import static seedu.address.model.Model.PREDICATE_SHOW_ONLY_RECRUITERS;
+
+import java.util.stream.Stream;
+
+import seedu.address.logic.commands.ListCommand;
+
+/**
+ * Parses input arguments and creates a new ListCommand object
+ */
+public class ListCommandParser implements Parser<ListCommand> {
+
+    /**
+     * Parses the given {@code String} of arguments in the context of the ListCommand
+     * and returns a ListCommand object for execution.
+     */
+    public ListCommand parse(String args) {
+        ArgumentMultimap argMultimap = ArgumentTokenizer.tokenize(args, FLAG_ORGANIZATION, FLAG_RECRUITER);
+
+        if (areFlagsPresent(argMultimap, FLAG_ORGANIZATION, FLAG_RECRUITER)) {
+            return new ListCommand(PREDICATE_SHOW_ALL_CONTACTS);
+        }
+
+        if (areFlagsPresent(argMultimap, FLAG_ORGANIZATION)) {
+            return new ListCommand(PREDICATE_SHOW_ONLY_ORGANIZATIONS);
+        } else if (areFlagsPresent(argMultimap, FLAG_RECRUITER)) {
+            return new ListCommand(PREDICATE_SHOW_ONLY_RECRUITERS);
+        }
+
+        return new ListCommand(PREDICATE_SHOW_ALL_CONTACTS);
+    }
+
+    /**
+     * Returns true if none of the flags contains empty {@code Optional} values in the given
+     * {@code ArgumentMultimap}.
+     */
+    private static boolean areFlagsPresent(ArgumentMultimap argumentMultimap, Flag... flags) {
+        return Stream.of(flags).allMatch(flag -> argumentMultimap.getValue(flag).isPresent());
+    }
+
+}

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

@@ -6,13 +6,17 @@
 import javafx.collections.ObservableList;
 import seedu.address.commons.core.GuiSettings;
 import seedu.address.model.person.Contact;
+import seedu.address.model.person.Type;
 
 /**
  * The API of the Model component.
  */
 public interface Model {
     /** {@code Predicate} that always evaluate to true */
-    Predicate<Contact> PREDICATE_SHOW_ALL_CONTACTS = unused -> true;
+    Predicate<Contact> PREDICATE_SHOW_ALL_CONTACTS = contact -> true;
+    Predicate<Contact> PREDICATE_SHOW_ONLY_ORGANIZATIONS = contact -> contact.getType() == Type.ORGANIZATION;
+    Predicate<Contact> PREDICATE_SHOW_ONLY_RECRUITERS = contact -> contact.getType() == Type.RECRUITER;
+
 
     /**
      * Replaces user prefs data with the data in {@code userPrefs}.

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

@@ -69,7 +69,7 @@ public void execute_commandExecutionError_throwsCommandException() {
     @Test
     public void execute_validCommand_success() throws Exception {
         String listCommand = ListCommand.COMMAND_WORD;
-        assertCommandSuccess(listCommand, ListCommand.MESSAGE_SUCCESS, model);
+        assertCommandSuccess(listCommand, ListCommand.MESSAGE_SUCCESS_ALL_CONTACTS, model);
     }
 
     @Test

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

@@ -2,6 +2,7 @@
 
 import static seedu.address.logic.commands.CommandTestUtil.assertCommandSuccess;
 import static seedu.address.logic.commands.CommandTestUtil.showContactAtIndex;
+import static seedu.address.model.Model.PREDICATE_SHOW_ALL_CONTACTS;
 import static seedu.address.testutil.TypicalContacts.getTypicalAddressBook;
 import static seedu.address.testutil.TypicalIndexes.INDEX_FIRST_CONTACT;
 
@@ -28,12 +29,14 @@ public void setUp() {
 
     @Test
     public void execute_listIsNotFiltered_showsSameList() {
-        assertCommandSuccess(new ListCommand(), model, ListCommand.MESSAGE_SUCCESS, expectedModel);
+        assertCommandSuccess(new ListCommand(PREDICATE_SHOW_ALL_CONTACTS), model,
+                ListCommand.MESSAGE_SUCCESS_ALL_CONTACTS, expectedModel);
     }
 
     @Test
     public void execute_listIsFiltered_showsEverything() {
         showContactAtIndex(model, INDEX_FIRST_CONTACT);
-        assertCommandSuccess(new ListCommand(), model, ListCommand.MESSAGE_SUCCESS, expectedModel);
+        assertCommandSuccess(new ListCommand(PREDICATE_SHOW_ALL_CONTACTS),
+                model, ListCommand.MESSAGE_SUCCESS_ALL_CONTACTS, expectedModel);
     }
 }