Add Start and Stop sessions on JAVA API

Issue-ID: CPS-899
Signed-off-by: emaclee <lee.anjella.macabuhay@est.tech>
Change-Id: Idbeb922790824b1ca601d6d4798df45efa57d685

2 files changed, 99 insertions, 0 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 78862d7233..bb3c2d07d4 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
@@ -56,6 +56,7 @@ import org.onap.cps.spi.model.DataNodeBuilder;
 import org.onap.cps.spi.repository.AnchorRepository;
 import org.onap.cps.spi.repository.DataspaceRepository;
 import org.onap.cps.spi.repository.FragmentRepository;
+import org.onap.cps.spi.utils.SessionManager;
 import org.onap.cps.utils.JsonObjectMapper;
 import org.springframework.dao.DataIntegrityViolationException;
 import org.springframework.stereotype.Service;
@@ -73,6 +74,8 @@ public class CpsDataPersistenceServiceImpl implements CpsDataPersistenceService
 
     private final JsonObjectMapper jsonObjectMapper;
 
+    private final SessionManager sessionManager;
+
     private static final String REG_EX_FOR_OPTIONAL_LIST_INDEX = "(\\[@[\\s\\S]+?]){0,1})";
     private static final Pattern REG_EX_PATTERN_FOR_LIST_ELEMENT_KEY_PREDICATE =
             Pattern.compile("\\[(\\@([^\\/]{0,9999}))\\]$");
@@ -199,6 +202,16 @@ public class CpsDataPersistenceServiceImpl implements CpsDataPersistenceService
             .collect(Collectors.toUnmodifiableList());
     }
 
+    @Override
+    public String startSession() {
+        return sessionManager.startSession();
+    }
+
+    @Override
+    public void closeSession(final String sessionId) {
+        sessionManager.closeSession(sessionId);
+    }
+
     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
new file mode 100644
index 0000000000..eb535ecc37
--- /dev/null
+++ b/cps-ri/src/main/java/org/onap/cps/spi/utils/SessionManager.java
@@ -0,0 +1,86 @@
+/*
+ *  ============LICENSE_START=======================================================
+ *  Copyright (C) 2021-2022 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 java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+import org.hibernate.HibernateException;
+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.springframework.stereotype.Component;
+
+@Component
+public class SessionManager {
+
+    private static SessionFactory sessionFactory;
+    private static Map<String, Session> sessionMap = new HashMap<>();
+
+    private synchronized void buildSessionFactory() {
+        if (sessionFactory == null) {
+            sessionFactory = new Configuration().configure("hibernate.cfg.xml")
+                    .addAnnotatedClass(AnchorEntity.class)
+                    .addAnnotatedClass(DataspaceEntity.class)
+                    .addAnnotatedClass(SchemaSetEntity.class)
+                    .addAnnotatedClass(YangResourceEntity.class)
+                    .buildSessionFactory();
+        }
+    }
+
+    /**
+     * Starts a session which allows use of locks and batch interaction with the persistence service.
+     *
+     * @return Session ID string
+     */
+    public String startSession() {
+        buildSessionFactory();
+        final Session session = sessionFactory.openSession();
+        final String sessionId = UUID.randomUUID().toString();
+        sessionMap.put(sessionId, session);
+        session.beginTransaction();
+        return sessionId;
+    }
+
+    /**
+     * Close session.
+     *
+     * @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));
+        } catch (final HibernateException e) {
+            throw new SessionException(String.format("Unable to close session with session ID %s", sessionId));
+        }
+        sessionMap.remove(sessionId);
+    }
+
+}
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