Add methods to Lock Anchor entity

Added separate integration and mock-based unit tests

Issue-ID: CPS-898
Signed-off-by: emaclee <lee.anjella.macabuhay@est.tech>
Change-Id: I14d1d1c41759ce028e2417fdd2df001280e19ab2

3 files changed, 131 insertions, 13 deletions

diff --git a/cps-ri/src/main/java/org/onap/cps/spi/impl/CpsDataPersistenceServiceImpl.java b/cps-ri/src/main/java/org/onap/cps/spi/impl/CpsDataPersistenceServiceImpl.java
index 847a1d129..daf4dd757 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/impl/CpsDataPersistenceServiceImpl.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/impl/CpsDataPersistenceServiceImpl.java
@@ -220,6 +220,12 @@ public class CpsDataPersistenceServiceImpl implements CpsDataPersistenceService
         sessionManager.closeSession(sessionId);
     }
 
+    @Override
+    public void lockAnchor(final String sessionId, final String dataspaceName,
+                            final String anchorName, final Long timeoutInMilliseconds) {
+        sessionManager.lockAnchor(sessionId, dataspaceName, anchorName, timeoutInMilliseconds);
+    }
+
     private static Set<String> processAncestorXpath(final List<FragmentEntity> fragmentEntities,
         final CpsPathQuery cpsPathQuery) {
         final Set<String> ancestorXpath = new HashSet<>();
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/utils/SessionManager.java b/cps-ri/src/main/java/org/onap/cps/spi/utils/SessionManager.java
index eb535ecc3..e2786887a 100644
--- a/cps-ri/src/main/java/org/onap/cps/spi/utils/SessionManager.java
+++ b/cps-ri/src/main/java/org/onap/cps/spi/utils/SessionManager.java
@@ -1,6 +1,6 @@
 /*
  *  ============LICENSE_START=======================================================
- *  Copyright (C) 2021-2022 Nordix Foundation
+ *  Copyright (C) 2022 Nordix Foundation
  *  ================================================================================
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -20,25 +20,43 @@
 
 package org.onap.cps.spi.utils;
 
-import java.util.HashMap;
-import java.util.Map;
+import com.google.common.util.concurrent.TimeLimiter;
+import com.google.common.util.concurrent.UncheckedExecutionException;
 import java.util.UUID;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.concurrent.ExecutionException;
+import java.util.concurrent.ExecutorService;
+import java.util.concurrent.Executors;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.TimeoutException;
+import lombok.RequiredArgsConstructor;
+import lombok.SneakyThrows;
+import lombok.extern.slf4j.Slf4j;
 import org.hibernate.HibernateException;
+import org.hibernate.LockMode;
 import org.hibernate.Session;
-import org.hibernate.SessionException;
 import org.hibernate.SessionFactory;
 import org.hibernate.cfg.Configuration;
 import org.onap.cps.spi.entities.AnchorEntity;
 import org.onap.cps.spi.entities.DataspaceEntity;
 import org.onap.cps.spi.entities.SchemaSetEntity;
 import org.onap.cps.spi.entities.YangResourceEntity;
+import org.onap.cps.spi.exceptions.SessionManagerException;
+import org.onap.cps.spi.exceptions.SessionTimeoutException;
+import org.onap.cps.spi.repository.AnchorRepository;
+import org.onap.cps.spi.repository.DataspaceRepository;
 import org.springframework.stereotype.Component;
 
+@RequiredArgsConstructor
+@Slf4j
 @Component
 public class SessionManager {
 
+    private final TimeLimiterProvider timeLimiterProvider;
+    private final DataspaceRepository dataspaceRepository;
+    private final AnchorRepository anchorRepository;
     private static SessionFactory sessionFactory;
-    private static Map<String, Session> sessionMap = new HashMap<>();
+    private static ConcurrentHashMap<String, Session> sessionMap = new ConcurrentHashMap<>();
 
     private synchronized void buildSessionFactory() {
         if (sessionFactory == null) {
@@ -67,20 +85,81 @@ public class SessionManager {
 
     /**
      * Close session.
+     * Locks will be released and changes will be committed.
      *
      * @param sessionId session ID
      */
     public void closeSession(final String sessionId) {
         try {
-            final Session currentSession = sessionMap.get(sessionId);
-            currentSession.getTransaction().commit();
-            currentSession.close();
-        } catch (final NullPointerException e) {
-            throw new SessionException(String.format("Session with session ID %s does not exist", sessionId));
+            final Session session = getSession(sessionId);
+            session.getTransaction().commit();
+            session.close();
         } catch (final HibernateException e) {
-            throw new SessionException(String.format("Unable to close session with session ID %s", sessionId));
+            throw new SessionManagerException("Cannot close session",
+                String.format("Unable to close session with session ID '%s'", sessionId), e);
+        } finally {
+            sessionMap.remove(sessionId);
         }
-        sessionMap.remove(sessionId);
     }
 
-}
\ No newline at end of file
+    /**
+     * Lock Anchor.
+     * To release locks(s), the session holding the lock(s) must be closed.
+     *
+     * @param sessionId session ID
+     * @param dataspaceName dataspace name
+     * @param anchorName anchor name
+     * @param timeoutInMilliseconds lock attempt timeout in milliseconds
+     */
+    @SneakyThrows
+    public void lockAnchor(final String sessionId, final String dataspaceName,
+                           final String anchorName, final Long timeoutInMilliseconds) {
+        final ExecutorService executorService = Executors.newSingleThreadExecutor();
+        final TimeLimiter timeLimiter = timeLimiterProvider.getTimeLimiter(executorService);
+
+        try {
+            timeLimiter.callWithTimeout(() -> {
+                applyPessimisticWriteLockOnAnchor(sessionId, dataspaceName, anchorName);
+                return null;
+            }, timeoutInMilliseconds, TimeUnit.MILLISECONDS);
+        } catch (final TimeoutException e) {
+            throw new SessionTimeoutException(
+                    "Timeout: Anchor locking failed",
+                    "The error could be caused by another session holding a lock on the specified table. "
+                            + "Retrying the sending the request could be required.", e);
+        } catch (final InterruptedException e) {
+            Thread.currentThread().interrupt();
+            throw new SessionManagerException("Operation interrupted", "This thread was interrupted.", e);
+        } catch (final ExecutionException | UncheckedExecutionException e) {
+            if (e.getCause() != null) {
+                throw e.getCause();
+            }
+            throw new SessionManagerException(
+                    "Operation Aborted",
+                    "The transaction request was aborted. "
+                            + "Retrying and checking all details are correct could be required", e);
+        } finally {
+            executorService.shutdownNow();
+        }
+    }
+
+    private void applyPessimisticWriteLockOnAnchor(final String sessionId, final String dataspaceName,
+                                                   final String anchorName) {
+        final Session session = getSession(sessionId);
+        final DataspaceEntity dataspaceEntity = dataspaceRepository.getByName(dataspaceName);
+        final AnchorEntity anchorEntity = anchorRepository.getByDataspaceAndName(dataspaceEntity, anchorName);
+        final int anchorId = anchorEntity.getId();
+        log.debug("Attempting to lock anchor {} for session {}", anchorName, sessionId);
+        session.get(AnchorEntity.class, anchorId, LockMode.PESSIMISTIC_WRITE);
+        log.info("Anchor {} successfully locked", anchorName);
+    }
+
+    private Session getSession(final String sessionId) {
+        final Session session = sessionMap.get(sessionId);
+        if (session == null) {
+            throw new SessionManagerException("Session not found",
+                String.format("Session with ID %s does not exist", sessionId));
+        }
+        return session;
+    }
+}
diff --git a/cps-ri/src/main/java/org/onap/cps/spi/utils/TimeLimiterProvider.java b/cps-ri/src/main/java/org/onap/cps/spi/utils/TimeLimiterProvider.java
new file mode 100644
index 000000000..2bd7ac376
--- /dev/null
+++ b/cps-ri/src/main/java/org/onap/cps/spi/utils/TimeLimiterProvider.java
@@ -0,0 +1,33 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2022 Nordix Foundation
+ *  ================================================================================
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *        http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  SPDX-License-Identifier: Apache-2.0
+ *  ============LICENSE_END=========================================================
+ */
+
+package org.onap.cps.spi.utils;
+
+import com.google.common.util.concurrent.SimpleTimeLimiter;
+import com.google.common.util.concurrent.TimeLimiter;
+import java.util.concurrent.ExecutorService;
+import org.springframework.stereotype.Component;
+
+@Component
+public class TimeLimiterProvider {
+    public TimeLimiter getTimeLimiter(final ExecutorService executorService) {
+        return SimpleTimeLimiter.create(executorService);
+    }
+}