org.jbpm.db.JbpmSession.java Source code

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Here is the source code for org.jbpm.db.JbpmSession.java

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/*
 * JBoss, Home of Professional Open Source
 * Copyright 2005, JBoss Inc., and individual contributors as indicated
 * by the @authors tag. See the copyright.txt in the distribution for a
 * full listing of individual contributors.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.jbpm.db;

import java.sql.Connection;
import java.util.LinkedList;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;
import org.jbpm.JbpmException;

/**
 * represents the connection to the jbpm database.
 * 
 * You can obtain a DbSession with
 * <pre>
 * DbSession dbSession = dbSessionFactory.openDbSession();
 * </pre>
 * or  
 * <pre>
 * Connection jdbcConnection = ...;
 * DbSession dbSession = dbSessionFactory.openDbSession(jdbcConnection);
 * </pre>  
 * The actual database operations are defined in the module sessions :
 * <ul>
 *   <li>{@link org.jbpm.db.GraphSession}</li>
 *   <li>{@link org.jbpm.db.TaskMgmtSession}</li>
 *   <li>{@link org.jbpm.db.LoggingSession}</li>
 *   <li>{@link org.jbpm.db.ContextSession}</li>
 * </ul>  
 * The easiest way to obtain the operations is like this :
 * <ul>
 *   <li><pre>jbpmSession.getGraphSession().someGraphDbMethod(...)</pre></li>
 *   <li><pre>jbpmSession.getTaskMgmtSession().someTaskDbMethod(...)</pre></li>
 *   <li><pre>jbpmSession.getLoggingSession().someLoggingDbMethod(...)</pre></li>
 *   <li><pre>jbpmSession.getContextSession().someContextDbMethod(...)</pre></li>
 * </ul>
 * 
 * @deprecated use {@link org.jbpm.JbpmContext} and {@link org.jbpm.JbpmConfiguration} instead.
 */
public class JbpmSession {

    static ThreadLocal currentJbpmSessionStack = new ThreadLocal();

    JbpmSessionFactory jbpmSessionFactory = null;
    Session session = null;
    Transaction transaction = null;

    GraphSession graphSession = null;
    ContextSession contextSession = null;
    TaskMgmtSession taskMgmtSession = null;
    LoggingSession loggingSession = null;
    JobSession jobSession = null;

    public JbpmSession(JbpmSessionFactory jbpmSessionFactory, Session session) {
        this.jbpmSessionFactory = jbpmSessionFactory;
        this.session = session;
        this.graphSession = new GraphSession(this);
        this.contextSession = new ContextSession(this);
        this.taskMgmtSession = new TaskMgmtSession(this);
        this.loggingSession = new LoggingSession(this);

        pushCurrentSession();
    }

    public JbpmSession(Session session) {
        this.session = session;
        this.graphSession = new GraphSession(this);
        this.contextSession = new ContextSession(this);
        this.taskMgmtSession = new TaskMgmtSession(this);
        this.loggingSession = new LoggingSession(this);
    }

    public JbpmSessionFactory getJbpmSessionFactory() {
        return jbpmSessionFactory;
    }

    public Connection getConnection() {
        try {
            return session.connection();
        } catch (Exception e) {
            log.error(e);
            handleException();
            throw new JbpmException("couldn't get the jdbc connection from hibernate", e);
        }
    }

    public Session getSession() {
        return session;
    }

    public Transaction getTransaction() {
        return transaction;
    }

    public void beginTransaction() {
        try {
            transaction = session.beginTransaction();
        } catch (Exception e) {
            log.error(e);
            handleException();
            throw new JbpmException("couldn't begin a transaction", e);
        }
    }

    public void commitTransaction() {
        if (transaction == null) {
            throw new JbpmException("can't commit : no transaction started");
        }
        try {
            session.flush();
            transaction.commit();
        } catch (Exception e) {
            log.error(e);
            handleException();
            throw new JbpmException("couldn't commit transaction", e);
        } finally {
            transaction = null;
        }
    }

    public void rollbackTransaction() {
        if (transaction == null) {
            throw new JbpmException("can't rollback : no transaction started");
        }
        try {
            transaction.rollback();
        } catch (Exception e) {
            log.error(e);
            handleException();
            throw new JbpmException("couldn't rollback transaction", e);
        } finally {
            transaction = null;
        }
    }

    public void commitTransactionAndClose() {
        commitTransaction();
        close();
    }

    public void rollbackTransactionAndClose() {
        rollbackTransaction();
        close();
    }

    public GraphSession getGraphSession() {
        return graphSession;
    }

    public ContextSession getContextSession() {
        return contextSession;
    }

    public TaskMgmtSession getTaskMgmtSession() {
        return taskMgmtSession;
    }

    public LoggingSession getLoggingSession() {
        return loggingSession;
    }

    public JobSession getJobSession() {
        return jobSession;
    }

    public void close() {
        try {
            if ((session != null) && (session.isOpen())) {
                session.close();
            }
        } catch (Exception e) {
            log.error(e);
            throw new JbpmException("couldn't close the hibernate connection", e);
        } finally {
            popCurrentSession();
            session = null;
        }
    }

    /**
     * handles an exception that is thrown by hibernate.
     */
    void handleException() {
        // if hibernate throws an exception,  
        if (transaction != null) {
            try {
                // the transaction should be rolled back
                transaction.rollback();
            } catch (HibernateException e) {
                log.error("couldn't rollback hibernate transaction", e);
            }
            // and the hibernate session should be closed.
            close();
        }
    }

    public void pushCurrentSession() {
        LinkedList stack = (LinkedList) currentJbpmSessionStack.get();
        if (stack == null) {
            stack = new LinkedList();
            currentJbpmSessionStack.set(stack);
        }
        stack.addFirst(this);
    }

    /**
     * @deprecated use {@link org.jbpm.JbpmConfiguration#getCurrentJbpmContext()} instead.
     */
    public static JbpmSession getCurrentJbpmSession() {
        JbpmSession jbpmSession = null;
        LinkedList stack = (LinkedList) currentJbpmSessionStack.get();
        if ((stack != null) && (!stack.isEmpty())) {
            jbpmSession = (JbpmSession) stack.getFirst();
        }
        return jbpmSession;
    }

    public void popCurrentSession() {
        LinkedList stack = (LinkedList) currentJbpmSessionStack.get();
        if ((stack == null) || (stack.isEmpty()) || (stack.getFirst() != this)) {
            log.warn("can't pop current session: are you calling JbpmSession.close() multiple times ?");
        } else {
            stack.removeFirst();
        }
    }

    private static final Log log = LogFactory.getLog(JbpmSession.class);
}