Spring version upgrade, DownloaderImpl complete (need some tests!)

pom.xml

@@ -5,7 +5,7 @@
 	<parent>
 		<groupId>org.springframework.boot</groupId>
 		<artifactId>spring-boot-starter-parent</artifactId>
-		<version>2.2.6.RELEASE</version>
+		<version>2.3.2.RELEASE</version>
 		<relativePath/> <!-- lookup parent from repository -->
 	</parent>
 	<groupId>me.bearns</groupId>

src/main/java/me/bearns/fias/service/Downloader.java

@@ -1,9 +1,9 @@
 package me.bearns.fias.service;
 
-import java.io.InputStream;
-import java.util.concurrent.Future;
+import java.io.File;
+import java.util.concurrent.CompletableFuture;
 
 public interface Downloader {
 
-    public Future<InputStream> download(String url);
+    public CompletableFuture<File> download(String url);
 }

src/main/java/me/bearns/fias/service/DownloaderImpl.java

@@ -1,28 +1,65 @@
 package me.bearns.fias.service;
 
-import java.io.InputStream;
-import java.util.concurrent.CompletableFuture;
-import java.util.concurrent.ExecutorService;
-import java.util.concurrent.Executors;
-import java.util.concurrent.Future;
+import org.springframework.stereotype.Component;
 
+import java.io.*;
+import java.net.URL;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.nio.file.StandardCopyOption;
+import java.util.concurrent.*;
+
+@Component
 public class DownloaderImpl implements Downloader {
 
     private static final ExecutorService pool = Executors.newCachedThreadPool();
+    private static final String BASE_DIRECTORY = "/var/opt/fias";
+    private  static final ConcurrentMap<String,CompletableFuture<File>> locks = new ConcurrentHashMap();
 
     @Override
-    public Future<InputStream> download(String url) {
+    public CompletableFuture<File> download(String url) {
 
-        CompletableFuture<InputStream> completableFuture
-                = new CompletableFuture<>();
+        CompletableFuture<File> start = new CompletableFuture<>();
+
+        //syncronized
+        final CompletableFuture<File> feature = locks.putIfAbsent(url, start);
+
+        //return earlier runned feature
+        if(feature != start) return feature;
 
         pool.submit(() -> {
-            InputStream is = null;
             //todo
 
-            completableFuture.complete(is);
+            final URL conn;
+            final Path path;
+
+            try{
+                conn = new URL(url);
+                path = Paths.get(BASE_DIRECTORY, conn.getFile());
+
+            } catch (IOException e) {
+                feature.obtrudeException(e);
+                return;
+            }
+
+            final File file = path.toFile();
+
+            if(!file.exists()) {
+
+                try (BufferedInputStream in = new BufferedInputStream(conn.openStream())) {
+
+                    Files.copy(in, path, StandardCopyOption.REPLACE_EXISTING);
+
+                } catch (IOException e) {
+                    // handle exception
+                    feature.obtrudeException(e);
+                }
+            }
+
+            feature.complete(file);
         });
 
-        return completableFuture;
+        return feature;
     }
 }

src/main/java/me/bearns/fias/service/FiasUpdater.java

@@ -5,7 +5,7 @@ import me.bearns.fias.repository.FiasVersionRepository;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.stereotype.Service;
 
-import java.io.InputStream;
+import java.io.File;
 import java.util.List;
 import java.util.concurrent.Future;
 import java.util.stream.Stream;
@@ -63,7 +63,7 @@ public class FiasUpdater implements Updater {
         updates.sort((o1, o2) -> Math.toIntExact(o1.getVersionId() - o2.getVersionId()));
 
         //just for test
-        final Stream<Future<InputStream>> stream = updates.stream().map(u -> downloader.download(reloadFlag ? u.getFiasCompleteXmlUrl() : u.getFiasDeltaXmlUrl()));
+        final Stream<Future<File>> stream = updates.stream().map(u -> downloader.download(reloadFlag ? u.getFiasCompleteXmlUrl() : u.getFiasDeltaXmlUrl()));
 
 
     }