From a8fa0312d1fe706d1ea626bd616b03a3ddb709be Mon Sep 17 00:00:00 2001
From: George Kalampokis <gkalampokis@cite.gr>
Date: Fri, 14 Feb 2020 10:35:19 +0200
Subject: [PATCH] Fix issue when multiple locks are in DB

---
 .../eu/eudat/logic/managers/LockManager.java  | 39 ++++++++++++++-----
 1 file changed, 29 insertions(+), 10 deletions(-)

diff --git a/dmp-backend/web/src/main/java/eu/eudat/logic/managers/LockManager.java b/dmp-backend/web/src/main/java/eu/eudat/logic/managers/LockManager.java
index 4d2a21419..46a900e3e 100644
--- a/dmp-backend/web/src/main/java/eu/eudat/logic/managers/LockManager.java
+++ b/dmp-backend/web/src/main/java/eu/eudat/logic/managers/LockManager.java
@@ -9,11 +9,14 @@ import org.springframework.core.env.Environment;
 import org.springframework.stereotype.Component;
 
 import javax.persistence.NoResultException;
+import java.util.Comparator;
 import java.util.Date;
+import java.util.List;
 import java.util.UUID;
 
 @Component
 public class LockManager {
+	private final Comparator<eu.eudat.data.entities.Lock> compareByTouchedAt = Comparator.comparing(o ->  o.getTouchedAt().getTime());
 
 	private ApiContext apiContext;
 	private Environment environment;
@@ -34,7 +37,7 @@ public class LockManager {
 					}
 				}
 			}catch(NoResultException e) {
-				return  new eu.eudat.data.entities.Lock();
+				lock.setId(null);
 			}
 		}
 		eu.eudat.data.entities.Lock newLock = lock.toDataModel();
@@ -47,31 +50,47 @@ public class LockManager {
 		LockCriteria criteria = new LockCriteria();
 		criteria.setTarget(UUID.fromString(targetId));
 		Long availableLocks = this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().getWithCriteria(criteria).count();
-		if (availableLocks > 0) {
+		if (availableLocks == 1) {
 			eu.eudat.data.entities.Lock lock = this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().getWithCriteria(criteria).getSingle();
 			if (lock.getLockedBy().getId().equals(principal.getId())) {
 				lock.setTouchedAt(new Date());
 				this.createOrUpdate(new Lock().fromDataModel(lock), principal);
 				return false;
 			}
-			if (new Date().getTime() - lock.getTouchedAt().getTime() > environment.getProperty("database.lock-fail-interval", Integer.class)) {
-				this.forceUnlock(targetId);
-				return false;
+			if (this.forceUnlock(targetId) > 0){
+				return true;
 			}
-			return true;
+		} else if (availableLocks > 1) {
+			this.forceUnlock(targetId);
+			return this.isLocked(targetId, principal);
 		}
 		return false;
 	}
 
-
-	private void forceUnlock(String targetId) throws Exception {
+	private Long forceUnlock(String targetId) {
 		LockCriteria criteria = new LockCriteria();
 		criteria.setTarget(UUID.fromString(targetId));
 		Long availableLocks = this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().getWithCriteria(criteria).count();
+		Long deletedLocks = 0L;
 		if (availableLocks > 0) {
-			eu.eudat.data.entities.Lock lock = this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().getWithCriteria(criteria).getSingle();
-			this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().delete(lock);
+			List<eu.eudat.data.entities.Lock> locks = this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().getWithCriteria(criteria).toList();
+			for (eu.eudat.data.entities.Lock lock : locks) {
+				if (new Date().getTime() - lock.getTouchedAt().getTime() > environment.getProperty("database.lock-fail-interval", Integer.class)) {
+					this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().delete(lock);
+					deletedLocks++;
+				}
+			}
+			if (deletedLocks == 0) {
+				eu.eudat.data.entities.Lock recentlock = locks.stream().max(compareByTouchedAt).get();
+				for (eu.eudat.data.entities.Lock lock : locks) {
+					if (lock != recentlock) {
+						this.apiContext.getOperationsContext().getDatabaseRepository().getLockDao().delete(lock);
+						deletedLocks++;
+					}
+				}
+			}
 		}
+		return availableLocks - deletedLocks;
 	}
 
 	public void unlock(String targetId, Principal principal) throws Exception {