#27 -- add multithreading

src/main/java/ru/ulstu/extractor/service/GitRepositoryService.java

@@ -45,6 +45,7 @@ import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
 import java.util.Optional;
+import java.util.concurrent.CopyOnWriteArrayList;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Future;
@@ -59,6 +60,7 @@ public class GitRepositoryService {
     @Value("${extractor.custom-projects-dir}")
     private String customProjectsDir;
     private final ExecutorService executorService = Executors.newFixedThreadPool(4);
+    private final ExecutorService executorServiceCommits = Executors.newFixedThreadPool(4);
 
     private final StructuralUnitService structuralUnitService;
 
@@ -109,22 +111,34 @@ public class GitRepositoryService {
         List<RevCommit> commits = new ArrayList<>();
         git.log().setSkip(commitsFrom).setMaxCount(commitsTo - commitsFrom).call().forEach(commits::add);
 
-        List<Commit> list = new ArrayList<>();
+        List<Commit> list = new CopyOnWriteArrayList<>();
         RevCommit prevCommit = null;
         LOG.debug("Start analyse {} commits", commits.size());
         LOG.debug(" {} to {} commits", commitsFrom, commitsTo);
+        List<Future<Commit>> futureCommits = new ArrayList<>();
         for (RevCommit revCommit : commits) {
-            Commit commit = new Commit(
-                    revCommit.getFullMessage(),
-                    new Author(revCommit.getAuthorIdent().getName()),
-                    Date.from(Instant.ofEpochSecond(revCommit.getCommitTime())),
-                    revCommit.getName());
-            if (prevCommit != null) {
-                commit.setFileChanges(findDiffBetweenTwoRevisions(revCommit, prevCommit, localRepo));
-            }
-            list.add(commit);
+            final RevCommit forPrevCommit = prevCommit;
+            futureCommits.add(executorServiceCommits.submit(() -> {
+                Commit commit = new Commit(
+                        revCommit.getFullMessage(),
+                        new Author(revCommit.getAuthorIdent().getName()),
+                        Date.from(Instant.ofEpochSecond(revCommit.getCommitTime())),
+                        revCommit.getName());
+                if (forPrevCommit != null) {
+                    commit.setFileChanges(findDiffBetweenTwoRevisions(revCommit, forPrevCommit, localRepo));
+                }
+                list.add(commit);
+                return commit;
+            }));
             prevCommit = revCommit;
         }
+        futureCommits.forEach(fc -> {
+            try {
+                fc.get();
+            } catch (Exception e) {
+                LOG.debug(e.getMessage());
+            }
+        });
         git.close();
         localRepo.close();
         return list;