[W8.6b][W09-B4] Chua Li Qun Shawn

src/seedu/addressbook/data/tag/Tagging.java

@@ -0,0 +1,93 @@
+package seedu.addressbook.data.tag;
+
+import seedu.addressbook.data.person.Person;
+
+import java.util.ArrayList;
+import java.util.Objects;
+
+/**
+ * Represents addition or deletion of tag for a person during a session
+ *
+ * Used for displaying tags changed at the end of a session
+ */
+
+public class Tagging {
+    private static ArrayList<Tagging> taggings;
+
+    public enum Action {
+        ADD, DELETE
+    }
+
+    private static final String ADD_TAG_SIGN = "+";
+    private static final String DELETE_TAG_SIGN = "-";
+
+    private final Person person;
+    private final Tag tag;
+    private final Action action;
+
+    /**
+     * @param person person whose tag was changed
+     * @param tag tag that was changed
+     * @param action type of action executed
+     */
+    public Tagging(Person person, Tag tag, Action action) {
+        this.person = person;
+        this.tag = tag;
+        this.action = action;
+    }
+
+    /**
+     * Adds tagging to class-level variable that stores all taggings
+     */
+    public static void addTagging(Tagging tagging) {
+        taggings.add(tagging);
+    }
+
+    /**
+     * Accessor method for obtaining taggings.
+     * @return all Taggings, representing all changes made to tags since start of session
+     */
+    public static ArrayList<Tagging> getTaggings() {
+        return taggings;
+    }
+
+    public Person getPerson() {
+        return person;
+    }
+
+    public Tag getTag() {
+        return tag;
+    }
+
+    public Action getAction() {
+        return action;
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        return obj == this // short circuit if same object
+                || obj instanceof Tagging // instanceof handles null
+                && ((Tagging) obj).getPerson().equals(this.person)
+                && ((Tagging) obj).getTag().equals(this.tag)
+                && ((Tagging) obj).getAction().equals(this.getAction());
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(person, tag, action);
+    }
+
+    @Override
+    public String toString() {
+        StringBuilder builder = new StringBuilder();
+
+        if (this.action == Action.ADD) {
+            builder.append(ADD_TAG_SIGN);
+        } else {
+            builder.append(DELETE_TAG_SIGN);
+        }
+
+        builder.append(" " + person.getName() + " " + tag);
+        return builder.toString();
+    }
+}