hw3: add javadoc everywhere

hw3/src/strategy/SortByDate.java

@@ -5,6 +5,9 @@ import model.Photo;
 import java.util.Comparator;
 import java.util.List;
 
+/**
+ * A sorting strategy that sorts photos by date.
+ */
 public class SortByDate implements SortingStrategy<Photo> {
     @Override
     public List<Photo> sort(List<Photo> photos) {

hw3/src/strategy/SortByName.java

@@ -5,6 +5,9 @@ import model.Photo;
 import java.util.Comparator;
 import java.util.List;
 
+/**
+ * A sorting strategy that sorts photos by name.
+ */
 public class SortByName implements SortingStrategy<Photo> {
     @Override
     public List<Photo> sort(List<Photo> photos) {

hw3/src/strategy/SortBySize.java

@@ -5,6 +5,9 @@ import model.Photo;
 import java.util.Comparator;
 import java.util.List;
 
+/**
+ * A sorting strategy that sorts photos by size.
+ */
 public class SortBySize implements SortingStrategy<Photo> {
     @Override
     public List<Photo> sort(List<Photo> photos) {

hw3/src/strategy/SortingStrategy.java

@@ -2,6 +2,11 @@ package strategy;
 
 import java.util.List;
 
+/**
+ * Interface for sorting strategies.
+ *
+ * @param <T> the type of elements to be sorted
+ */
 public interface SortingStrategy<T> {
     List<T> sort(List<T> photos);
 }