com.agapsys.web.toolkit.modules.PersistenceModule Maven / Gradle / Ivy

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/*
 * Copyright 2015-2016 Agapsys Tecnologia Ltda-ME.
 *
 * 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.
 */

package com.agapsys.web.toolkit.modules;

import com.agapsys.web.toolkit.AbstractApplication;
import com.agapsys.web.toolkit.Module;
import com.agapsys.web.toolkit.utils.Settings;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.Map.Entry;
import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.FlushModeType;
import javax.persistence.Persistence;

/**
 * Represents a JPA persistence module.
 */
public class PersistenceModule extends Module {

    // 
    // =========================================================================
    public static final String SETTINGS_GROUP_NAME = PersistenceModule.class.getName();

    public static final String KEY_JDBC_PASSWORD = "javax.persistence.jdbc.password";

    public static final String DEFAULT_PERSISTENCE_UNIT_NAME = "default";

    public static interface EmFactory {
        public EntityManager getInstance();
    }
    // =========================================================================
    // 

    private final String persistenceUnitName;
    private final EmFactory defaultFactory = new EmFactory() {
        @Override
        public EntityManager getInstance() {
            EntityManager em = emf.createEntityManager();
            em.setFlushMode(FlushModeType.COMMIT);
            return em;
        }
    };

    private EntityManagerFactory emf = null;
    private char[] jdbcPassword = null;
    private EmFactory emFactory = null;

    /**
     * Default constructor. Default persistence name equals to {@linkplain PersistenceModule#DEFAULT_PERSISTENCE_UNIT_NAME}.
     */
    public PersistenceModule() {
        this(DEFAULT_PERSISTENCE_UNIT_NAME);
    }

    /**
     * Constructor. Allows a custom persistence unit name.
     *
     * @param persistenceUnitName persistence unit name used by this module.
     */
    public PersistenceModule(String persistenceUnitName) {
        if (persistenceUnitName == null || persistenceUnitName.trim().isEmpty())
            throw new IllegalArgumentException("Null/Empty name");

        this.persistenceUnitName = persistenceUnitName;
    }

    @Override
    protected final String getSettingsSection() {
        return SETTINGS_GROUP_NAME;
    }

    /**
     * Returns JDBC password.
     *
     * @return JDBC password.
     */
    protected char[] getJdbcPassword() {
        return jdbcPassword;
    }

    /**
     * Return the name of persistence unit associated with this instance.
     *
     * @return the name of persistence unit associated with this instance.
     */
    protected String getPersistenceUnitName() {
        return persistenceUnitName;
    }

    /**
     * Returns additional properties to be used when creating the internal
     * entity manager factory.
     *
     * @param app associated application.
     * @return additional properties to be used.
     */
    protected Map getAdditionalProperties(AbstractApplication app) {
        Settings settings = getSettings();

        Map settingsMap = new LinkedHashMap<>();
        for (Entry entry : settings.entrySet()) {
            settingsMap.put(entry.getKey(), entry.getValue());
        }

        Map propertyMap = new LinkedHashMap(settingsMap);

        String strJdbcPassword = settings.getProperty(KEY_JDBC_PASSWORD, null);

        if (strJdbcPassword == null) {
            jdbcPassword = null;
        } else {
            jdbcPassword = strJdbcPassword.toCharArray();
            propertyMap.put(KEY_JDBC_PASSWORD, new String(jdbcPassword));
        }

        return propertyMap;
    }

    @Override
    protected void onInit(AbstractApplication app) {
        super.onInit(app);
        emf = Persistence.createEntityManagerFactory(getPersistenceUnitName(), getAdditionalProperties(app));
    }

    @Override
    protected void onStop() {
        super.onStop();

        emf.close();
        emf = null;
    }

    /**
     * Returns the EmFactory instance to be used by this module.
     *
     * @return EmFactory instance associated with this module instance.
     */
    protected EmFactory getEmFactory() {
        return defaultFactory;
    }

    private EmFactory __getEmFactory() {
        synchronized(this) {
            if (emFactory == null) {
                emFactory = getEmFactory();
            }

            return emFactory;
        }
    }

    /**
     * Returns an entity manager to be used by application.
     *
     * @return an entity manager to be used by application.
     */
    public final EntityManager getEntityManager() {
        synchronized(this) {
            if (!isActive())
                throw new IllegalStateException("Module is not active");

            return __getEmFactory().getInstance();
        }
    }

}