de.topicmapslab.majortom.database.jdbc.core.SessionImpl.java Source code

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Here is the source code for de.topicmapslab.majortom.database.jdbc.core.SessionImpl.java

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/*******************************************************************************
 * Copyright 2010, Topic Map Lab ( http://www.topicmapslab.de )
 * 
 * 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 de.topicmapslab.majortom.database.jdbc.core;

import java.sql.Connection;
import java.sql.SQLException;

import org.apache.commons.dbcp.BasicDataSource;

import de.topicmapslab.majortom.database.jdbc.model.IConnectionProvider;
import de.topicmapslab.majortom.database.jdbc.model.IQueryProcessor;
import de.topicmapslab.majortom.database.jdbc.model.ISession;
import de.topicmapslab.majortom.database.store.JdbcTopicMapStore;
import de.topicmapslab.majortom.model.exception.TopicMapStoreException;

/**
 * @author Sven Krosse
 * 
 */
public abstract class SessionImpl implements ISession {

    // private final String user;
    // private final String password;
    // private final String url;
    private IQueryProcessor processor;
    private Connection connection;
    private final IConnectionProvider connectionProvider;
    private final boolean autoCommit;
    private BasicDataSource bds;

    // private HashMap<Connection, IQueryProcessor> processors;

    /**
     * Constructor
     * 
     * @param connectionProvider
     *            the parent connection provider
     * @param url
     *            the URL
     * @param user
     *            the user
     * @param password
     *            the password
     */
    public <T extends IConnectionProvider> SessionImpl(final T connectionProvider, final String url,
            final String user, final String password) {
        // this.url = url;
        // this.user = user;
        // this.password = password;
        this.connectionProvider = connectionProvider;
        this.autoCommit = true;
        bds = new BasicDataSource();
        bds.setDriverClassName(connectionProvider.getDriverClassName());
        bds.setUsername(user);
        bds.setPassword(password);
        bds.setUrl(url);
        bds.setDefaultAutoCommit(isAutoCommit());
        bds.setMaxActive(20);
        bds.setPoolPreparedStatements(true);
        // processors = new HashMap<Connection, IQueryProcessor>();
    }

    /**
     * {@inheritDoc}
     */
    @SuppressWarnings("unchecked")
    public <T extends IQueryProcessor> T getProcessor() throws TopicMapStoreException {
        try {
            if (!isAlive()) {
                connection = openConnection();
                processor = createProcessor(connection);
            }
        } catch (SQLException e) {
            throw new TopicMapStoreException("Cannot initialize session for database!", e);
        }
        return (T) processor;
    }

    /**
     * Internal method to create a processor instance for the given connection
     * 
     * @param <T>
     *            the type of processor
     * @param connection
     *            the connection
     * @return the created processor
     * @throws TopicMapStoreException
     *             thrown if operation fails
     */
    protected abstract <T extends IQueryProcessor> T createProcessor(Connection connection)
            throws TopicMapStoreException;

    /**
     * {@inheritDoc}
     */
    public void close() throws SQLException {
        if (processor != null) {
            processor.close();
        }
        if (connection != null && !connection.isClosed()) {
            connection.close();
        }
    }

    /**
     * {@inheritDoc}
     */
    public void commit() throws SQLException {
        if (!isAutoCommit()) {
            getConnection().commit();
        }
    }

    /**
     * Internal method to check if the connection is still alive
     * 
     * @return <code>true</code> if the connection is alive <code>false</code> otherwise
     */
    protected boolean isAlive() throws SQLException {
        if (connection == null || connection.isClosed()) {
            return false;
        }
        try {
            connection.setAutoCommit(true);
        } catch (Exception e) {
            close();
            return false;
        }
        return true;
    }

    /**
     * Internal method to open a connection to the defined database
     * 
     * @return the connection
     * @throws SQLException
     *             thrown if connection cannot be established
     */
    protected Connection openConnection() throws SQLException {
        // connection = DriverManager.getConnection(url, user, password);
        connection = bds.getConnection();
        connection.setAutoCommit(isAutoCommit());
        return connection;
    }

    /**
     * {@inheritDoc}
     */
    public Connection getConnection() throws SQLException {
        if (!isAlive()) {
            connection = openConnection();
            processor = createProcessor(connection);
        }
        return connection;
    }

    /**
     * {@inheritDoc}
     */
    public JdbcTopicMapStore getTopicMapStore() {
        return getConnectionProvider().getTopicMapStore();
    }

    /**
     * {@inheritDoc}
     */
    public IConnectionProvider getConnectionProvider() {
        return connectionProvider;
    }

    /**
     * {@inheritDoc}
     */
    public boolean isAutoCommit() {
        return autoCommit;
    }

}