Add method to fetch all photo paths and optimize database population logic

src/main/java/com/example/PhotoGallery/Repos/PhotoRepo.java

@@ -1,6 +1,7 @@
 package com.example.PhotoGallery.Repos;
 
 import java.util.List;
+import java.util.Set;
 
 import org.springframework.data.jpa.repository.JpaRepository;
 import org.springframework.data.jpa.repository.Query;
@@ -15,4 +16,7 @@ public interface PhotoRepo extends JpaRepository<Photo, Long> {
 
     @Query("SELECT p.thumbnail_path FROM Photo p")
     List<String> findAllThumbnailPaths();
+
+    @Query("SELECT p.path FROM Photo p")
+    Set<String> findAllPaths();
 }

src/main/java/com/example/PhotoGallery/Services/DatabasePopulation.java

@@ -6,8 +6,10 @@ import java.nio.file.Files;
 import java.nio.file.Path;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;
+import java.util.stream.Collectors;
 
 import org.json.simple.JSONObject;
 import org.springframework.beans.factory.annotation.Autowired;
@@ -40,10 +42,14 @@ public class DatabasePopulation {
     private String originalImgPath;
 
     public void populateDatabase() {
+        //Fetch all existing photo paths from the DB in one query.
+        Set<String> existingPaths = photoRepo.findAllPaths();
 
-        for (String path : getImagePaths()) {
+        //Get all image paths from the file system.
+        List<String> allImagePaths = getImagePaths();
 
-            if (!photoRepo.existsByPath(path)) {
+        for (String path : allImagePaths) {
+            if (!existingPaths.contains(path)) {
 
                 if (!imageCompressor.compressImage(path, compressedImgPath)) {
                     continue;

src/main/java/com/example/PhotoGallery/Services/PhotoService.java

@@ -4,7 +4,6 @@ import java.util.List;
 
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
-import org.springframework.ui.Model;
 
 import com.example.PhotoGallery.Models.Photo;
 import com.example.PhotoGallery.Repos.PhotoRepo;