CategoryItem: add javadocs to the file

app/src/main/java/fr/free/nrw/commons/category/CategoryItem.java

@@ -3,6 +3,10 @@
 import android.os.Parcel;
 import android.os.Parcelable;
 
+/**
+ * Represents a Category Item.
+ * Implemented as Parcelable so that its object could be parsed between activity components.
+ */
 public class CategoryItem implements Parcelable {
     private final String name;
     private boolean selected;
@@ -24,28 +28,53 @@ public CategoryItem(String name, boolean selected) {
         this.selected = selected;
     }
 
+    /**
+     * Reads from the received Parcel
+     * @param in
+     */
     private CategoryItem(Parcel in) {
         name = in.readString();
         selected = in.readInt() == 1;
     }
 
+    /**
+     * Gets Name
+     * @return
+     */
     public String getName() {
         return name;
     }
 
+    /**
+     * Checks if that Category Item has been selected.
+     * @return
+     */
     public boolean isSelected() {
         return selected;
     }
 
+    /**
+     * Selects the Category Item.
+     * @param selected
+     */
     public void setSelected(boolean selected) {
         this.selected = selected;
     }
 
+    /**
+     * Used by Parcelable
+     * @return
+     */
     @Override
     public int describeContents() {
         return 0;
     }
 
+    /**
+     * Writes to the received Parcel
+     * @param parcel
+     * @param flags
+     */
     @Override
     public void writeToParcel(Parcel parcel, int flags) {
         parcel.writeString(name);
@@ -67,11 +96,17 @@ public boolean equals(Object o) {
 
     }
 
+    /**
+     * Returns hash code for current object
+     */
     @Override
     public int hashCode() {
         return name.hashCode();
     }
 
+    /**
+     * Return String form of current object
+     */
     @Override
     public String toString() {
         return "CategoryItem: '" + name + '\'';