Standardize #equals(Object) implementations

src/main/java/seedu/address/AppParameters.java

@@ -49,12 +49,13 @@ public boolean equals(Object other) {
             return true;
         }
 
+        // instanceof handles nulls
         if (!(other instanceof AppParameters)) {
             return false;
         }
 
         AppParameters otherAppParameters = (AppParameters) other;
-        return Objects.equals(getConfigPath(), otherAppParameters.getConfigPath());
+        return Objects.equals(configPath, otherAppParameters.configPath);
     }
 
     @Override

src/main/java/seedu/address/commons/core/Config.java

@@ -37,14 +37,15 @@ public boolean equals(Object other) {
         if (other == this) {
             return true;
         }
-        if (!(other instanceof Config)) { //this handles null as well.
+
+        // instanceof handles nulls
+        if (!(other instanceof Config)) {
             return false;
         }
 
-        Config o = (Config) other;
-
-        return Objects.equals(logLevel, o.logLevel)
-                && Objects.equals(userPrefsFilePath, o.userPrefsFilePath);
+        Config otherConfig = (Config) other;
+        return Objects.equals(logLevel, otherConfig.logLevel)
+                && Objects.equals(userPrefsFilePath, otherConfig.userPrefsFilePath);
     }
 
     @Override

src/main/java/seedu/address/commons/core/GuiSettings.java

@@ -46,15 +46,16 @@ public boolean equals(Object other) {
         if (other == this) {
             return true;
         }
-        if (!(other instanceof GuiSettings)) { //this handles null as well.
+
+        // instanceof handles nulls
+        if (!(other instanceof GuiSettings)) {
             return false;
         }
 
-        GuiSettings o = (GuiSettings) other;
-
-        return windowWidth == o.windowWidth
-                && windowHeight == o.windowHeight
-                && Objects.equals(windowCoordinates, o.windowCoordinates);
+        GuiSettings otherGuiSettings = (GuiSettings) other;
+        return windowWidth == otherGuiSettings.windowWidth
+                && windowHeight == otherGuiSettings.windowHeight
+                && Objects.equals(windowCoordinates, otherGuiSettings.windowCoordinates);
     }
 
     @Override

src/main/java/seedu/address/commons/core/Version.java

@@ -90,16 +90,21 @@ public int compareTo(Version other) {
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (obj == null) {
-            return false;
+    public boolean equals(Object other) {
+        if (other == this) {
+            return true;
         }
-        if (!(obj instanceof Version)) {
+
+        // instanceof handles nulls
+        if (!(other instanceof Version)) {
             return false;
         }
-        final Version other = (Version) obj;
 
-        return compareTo(other) == 0;
+        Version otherVersion = (Version) other;
+        return major == otherVersion.major
+                && minor == otherVersion.minor
+                && patch == otherVersion.patch
+                && isEarlyAccess == otherVersion.isEarlyAccess;
     }
 
     @Override

src/main/java/seedu/address/commons/core/index/Index.java

@@ -47,8 +47,16 @@ public static Index fromOneBased(int oneBasedIndex) {
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof Index // instanceof handles nulls
-                && zeroBasedIndex == ((Index) other).zeroBasedIndex); // state check
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof Index)) {
+            return false;
+        }
+
+        Index otherIndex = (Index) other;
+        return zeroBasedIndex == otherIndex.zeroBasedIndex;
     }
 }

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

@@ -35,20 +35,18 @@ public ObservableList<String> getHistory() {
     }
 
     @Override
-    public boolean equals(Object obj) {
-        // short circuit if same object
-        if (obj == this) {
+    public boolean equals(Object other) {
+        if (other == this) {
             return true;
         }
 
         // instanceof handles nulls
-        if (!(obj instanceof CommandHistory)) {
+        if (!(other instanceof CommandHistory)) {
             return false;
         }
 
-        // state check
-        CommandHistory other = (CommandHistory) obj;
-        return userInputHistory.equals(other.userInputHistory);
+        CommandHistory otherCommandHistory = (CommandHistory) other;
+        return userInputHistory.equals(otherCommandHistory.userInputHistory);
     }
 
     @Override

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

@@ -62,8 +62,16 @@ public CommandResult execute(Model model, CommandHistory history) throws Command
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof AddCommand // instanceof handles nulls
-                && toAdd.equals(((AddCommand) other).toAdd));
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof AddCommand)) {
+            return false;
+        }
+
+        AddCommand otherAddCommand = (AddCommand) other;
+        return toAdd.equals(otherAddCommand.toAdd);
     }
 }

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

@@ -48,8 +48,16 @@ public CommandResult execute(Model model, CommandHistory history) throws Command
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof DeleteCommand // instanceof handles nulls
-                && targetIndex.equals(((DeleteCommand) other).targetIndex)); // state check
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof DeleteCommand)) {
+            return false;
+        }
+
+        DeleteCommand otherDeleteCommand = (DeleteCommand) other;
+        return targetIndex.equals(otherDeleteCommand.targetIndex);
     }
 }

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

@@ -11,6 +11,7 @@
 import java.util.Collections;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 
@@ -106,7 +107,6 @@ private static Person createEditedPerson(Person personToEdit, EditPersonDescript
 
     @Override
     public boolean equals(Object other) {
-        // short circuit if same object
         if (other == this) {
             return true;
         }
@@ -116,10 +116,9 @@ public boolean equals(Object other) {
             return false;
         }
 
-        // state check
-        EditCommand e = (EditCommand) other;
-        return index.equals(e.index)
-                && editPersonDescriptor.equals(e.editPersonDescriptor);
+        EditCommand otherEditCommand = (EditCommand) other;
+        return index.equals(otherEditCommand.index)
+                && editPersonDescriptor.equals(otherEditCommand.editPersonDescriptor);
     }
 
     /**
@@ -205,7 +204,6 @@ public Optional<Set<Tag>> getTags() {
 
         @Override
         public boolean equals(Object other) {
-            // short circuit if same object
             if (other == this) {
                 return true;
             }
@@ -215,14 +213,12 @@ public boolean equals(Object other) {
                 return false;
             }
 
-            // state check
-            EditPersonDescriptor e = (EditPersonDescriptor) other;
-
-            return getName().equals(e.getName())
-                    && getPhone().equals(e.getPhone())
-                    && getEmail().equals(e.getEmail())
-                    && getAddress().equals(e.getAddress())
-                    && getTags().equals(e.getTags());
+            EditPersonDescriptor otherEditPersonDescriptor = (EditPersonDescriptor) other;
+            return Objects.equals(name, otherEditPersonDescriptor.name)
+                    && Objects.equals(phone, otherEditPersonDescriptor.phone)
+                    && Objects.equals(email, otherEditPersonDescriptor.email)
+                    && Objects.equals(address, otherEditPersonDescriptor.address)
+                    && Objects.equals(tags, otherEditPersonDescriptor.tags);
         }
     }
 }

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

@@ -36,8 +36,16 @@ public CommandResult execute(Model model, CommandHistory history) {
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof FindCommand // instanceof handles nulls
-                && predicate.equals(((FindCommand) other).predicate)); // state check
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof FindCommand)) {
+            return false;
+        }
+
+        FindCommand otherFindCommand = (FindCommand) other;
+        return predicate.equals(otherFindCommand.predicate);
     }
 }

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

@@ -48,8 +48,16 @@ public CommandResult execute(Model model, CommandHistory history) throws Command
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof SelectCommand // instanceof handles nulls
-                && targetIndex.equals(((SelectCommand) other).targetIndex)); // state check
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof SelectCommand)) {
+            return false;
+        }
+
+        SelectCommand otherSelectCommand = (SelectCommand) other;
+        return targetIndex.equals(otherSelectCommand.targetIndex);
     }
 }

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

@@ -25,15 +25,17 @@ public int hashCode() {
     }
 
     @Override
-    public boolean equals(Object obj) {
-        if (!(obj instanceof Prefix)) {
-            return false;
-        }
-        if (obj == this) {
+    public boolean equals(Object other) {
+        if (other == this) {
             return true;
         }
 
-        Prefix otherPrefix = (Prefix) obj;
-        return otherPrefix.getPrefix().equals(getPrefix());
+        // instanceof handles nulls
+        if (!(other instanceof Prefix)) {
+            return false;
+        }
+
+        Prefix otherPrefix = (Prefix) other;
+        return prefix.equals(otherPrefix.prefix);
     }
 }

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

@@ -132,9 +132,17 @@ public ObservableList<Person> getPersonList() {
 
     @Override
     public boolean equals(Object other) {
-        return other == this // short circuit if same object
-                || (other instanceof AddressBook // instanceof handles nulls
-                && persons.equals(((AddressBook) other).persons));
+        if (other == this) {
+            return true;
+        }
+
+        // instanceof handles nulls
+        if (!(other instanceof AddressBook)) {
+            return false;
+        }
+
+        AddressBook otherAddressBook = (AddressBook) other;
+        return persons.equals(otherAddressBook.persons);
     }
 
     @Override

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

@@ -213,23 +213,21 @@ private void ensureSelectedPersonIsValid(ListChangeListener.Change<? extends Per
     }
 
     @Override
-    public boolean equals(Object obj) {
-        // short circuit if same object
-        if (obj == this) {
+    public boolean equals(Object other) {
+        if (other == this) {
             return true;
         }
 
         // instanceof handles nulls
-        if (!(obj instanceof ModelManager)) {
+        if (!(other instanceof ModelManager)) {
             return false;
         }
 
-        // state check
-        ModelManager other = (ModelManager) obj;
-        return versionedAddressBook.equals(other.versionedAddressBook)
-                && userPrefs.equals(other.userPrefs)
-                && filteredPersons.equals(other.filteredPersons)
-                && Objects.equals(selectedPerson.get(), other.selectedPerson.get());
+        ModelManager otherModelManager = (ModelManager) other;
+        return versionedAddressBook.equals(otherModelManager.versionedAddressBook)
+                && userPrefs.equals(otherModelManager.userPrefs)
+                && filteredPersons.equals(otherModelManager.filteredPersons)
+                && Objects.equals(selectedPerson.get(), otherModelManager.selectedPerson.get());
     }
 
 }

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

@@ -61,14 +61,15 @@ public boolean equals(Object other) {
         if (other == this) {
             return true;
         }
-        if (!(other instanceof UserPrefs)) { //this handles null as well.
+
+        // instanceof handles nulls
+        if (!(other instanceof UserPrefs)) {
             return false;
         }
 
-        UserPrefs o = (UserPrefs) other;
-
-        return guiSettings.equals(o.guiSettings)
-                && addressBookFilePath.equals(o.addressBookFilePath);
+        UserPrefs otherUserPrefs = (UserPrefs) other;
+        return guiSettings.equals(otherUserPrefs.guiSettings)
+                && addressBookFilePath.equals(otherUserPrefs.addressBookFilePath);
     }
 
     @Override

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

@@ -72,7 +72,6 @@ public boolean canRedo() {
 
     @Override
     public boolean equals(Object other) {
-        // short circuit if same object
         if (other == this) {
             return true;
         }
@@ -83,8 +82,6 @@ public boolean equals(Object other) {
         }
 
         VersionedAddressBook otherVersionedAddressBook = (VersionedAddressBook) other;
-
-        // state check
         return super.equals(otherVersionedAddressBook)
                 && addressBookStateList.equals(otherVersionedAddressBook.addressBookStateList)
                 && currentStatePointer == otherVersionedAddressBook.currentStatePointer;