+/*-
+ * ============LICENSE_START=======================================================
+ * Copyright (C) 2021 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.policy.models.provider.impl;
+
+import java.io.Closeable;
+import java.util.Properties;
+import javax.ws.rs.core.Response;
+import lombok.Getter;
+import lombok.NonNull;
+import org.eclipse.persistence.config.PersistenceUnitProperties;
+import org.onap.policy.models.base.PfModelException;
+import org.onap.policy.models.dao.DaoParameters;
+import org.onap.policy.models.dao.PfDao;
+import org.onap.policy.models.dao.PfDaoFactory;
+import org.onap.policy.models.dao.impl.DefaultPfDao;
+import org.onap.policy.models.provider.PolicyModelsProviderParameters;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * This class provides an abstract models provider that can be used to initialise the database for any specialisation of
+ * the class.
+ */
+public abstract class AbstractModelsProvider implements Closeable {
+
+ private static final Logger LOGGER = LoggerFactory.getLogger(AbstractModelsProvider.class);
+
+ private final PolicyModelsProviderParameters parameters;
+
+ // Database connection and the DAO for reading and writing Policy Framework concepts
+ @Getter
+ private PfDao pfDao;
+
+ /**
+ * Constructor that takes the parameters.
+ *
+ * @param parameters the parameters for the provider
+ */
+ protected AbstractModelsProvider(@NonNull final PolicyModelsProviderParameters parameters) {
+ this.parameters = parameters;
+ }
+
+ /**
+ * Initialise the provider.
+ *
+ * @throws PfModelException in initialisation errors
+ */
+ public synchronized void init() throws PfModelException {
+ LOGGER.debug("opening the database connection to {} using persistence unit {}", parameters.getDatabaseUrl(),
+ parameters.getPersistenceUnit());
+
+ if (pfDao != null) {
+ String errorMessage = "provider is already initialized";
+ throw new PfModelException(Response.Status.NOT_ACCEPTABLE, errorMessage);
+ }
+
+ // Parameters for the DAO
+ final DaoParameters daoParameters = new DaoParameters();
+ daoParameters.setPluginClass(DefaultPfDao.class.getName());
+ daoParameters.setPersistenceUnit(parameters.getPersistenceUnit());
+
+ // @formatter:off
+ Properties jdbcProperties = new Properties();
+ jdbcProperties.setProperty(PersistenceUnitProperties.JDBC_DRIVER, parameters.getDatabaseDriver());
+ jdbcProperties.setProperty(PersistenceUnitProperties.JDBC_URL, parameters.getDatabaseUrl());
+ jdbcProperties.setProperty(PersistenceUnitProperties.JDBC_USER, parameters.getDatabaseUser());
+ jdbcProperties.setProperty(PersistenceUnitProperties.JDBC_PASSWORD, parameters.getDatabasePassword());
+ // @formatter:on
+
+ daoParameters.setJdbcProperties(jdbcProperties);
+
+ try {
+ pfDao = new PfDaoFactory().createPfDao(daoParameters);
+ pfDao.init(daoParameters);
+ } catch (Exception exc) {
+ String errorMessage = "could not create Data Access Object (DAO) using url \"" + parameters.getDatabaseUrl()
+ + "\" and persistence unit \"" + parameters.getPersistenceUnit() + "\"";
+
+ this.close();
+ throw new PfModelException(Response.Status.NOT_ACCEPTABLE, errorMessage, exc);
+ }
+ }
+
+ @Override
+ public synchronized void close() {
+ LOGGER.debug("closing the database connection to {} using persistence unit {}", parameters.getDatabaseUrl(),
+ parameters.getPersistenceUnit());
+
+ if (pfDao != null) {
+ pfDao.close();
+ pfDao = null;
+ }
+
+ LOGGER.debug("closed the database connection to {} using persistence unit {}", parameters.getDatabaseUrl(),
+ parameters.getPersistenceUnit());
+ }
+}