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panther » org » lateralnz » simpletrans » SimpleTransaction.java
/* ====================================================================
 * The LateralNZ Software License, Version 1.0
 *
 * Copyright (c) 2003 LateralNZ.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by 
 *        LateralNZ (http://www.lateralnz.org/) and other third parties."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "LateralNZ" must not be used to endorse or promote 
 *    products derived from this software without prior written 
 *    permission. For written permission, please 
 *    contact oss@lateralnz.org.
 *
 * 5. Products derived from this software may not be called "Panther", 
 *    or "Lateral" or "LateralNZ", nor may "PANTHER" or "LATERAL" or 
 *    "LATERALNZ" appear in their name, without prior written 
 *    permission of LateralNZ.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of LateralNZ.  For more
 * information on Lateral, please see http://www.lateralnz.com/ or
 * http://www.lateralnz.org
 *
 */
package org.lateralnz.simpletrans;

import java.util.Iterator;
import java.util.HashMap;
import java.util.Map;
import java.sql.SQLException;

import javax.transaction.Status;
import javax.transaction.Synchronization;
import javax.transaction.Transaction;
import javax.transaction.xa.XAResource;

import org.apache.log4j.Logger;

import org.lateralnz.common.util.DAOUtils;

/**
 * a 'simple' transaction storing a map of named 'transaction-aware' connections. This class
 * partially implements a javax.transaction.Transaction, but adds proprietary (to this package)
 * methods for adding TransConnection objects.
 * Note also that this isn't a true implementation of a transaction (by any stretch of
 * the imagination).  If two connections have been enlisted from different databases
 * and a commit succeeds on one, then fails on the other, your data will (obviously) end up
 * in an inconsistent state.
 *
 * @see org.lateralnz.panther.trans.TransConnection
 *
 * @author J R Briggs
 */
public class SimpleTransaction implements Transaction {
  private static final Logger log = Logger.getLogger(SimpleTransaction.class.getName());

  private Map connMap = new HashMap();    // the map of trans connections
  private int status;                     // the status of this transaction
  
 /**
  * create a new transaction and make it active
  */
  public SimpleTransaction() {
    if (log.isDebugEnabled()) {
      log.debug("starting new transaction");
    }
    status = Status.STATUS_ACTIVE;
  }
  
 /**
  * commit a transaction, and close any connections that have been flagged for
  * closing
  */
  public void commit() {
    status = Status.STATUS_COMMITTING;
    Iterator iter = connMap.values().iterator();
    while (iter.hasNext()) {
      TransConnection conn = (TransConnection)iter.next();
      try {
        conn.doCommit();
        
        if (conn.isCloseFlagged()) {
          conn.doClose();
          iter.remove();
        }
      }
      catch (SQLException se) {
        se.printStackTrace();
      }
    }
    status = Status.STATUS_COMMITTED;
  }
  
  public boolean delistResource(XAResource xAResource, int param) {
    TransConnection conn = (TransConnection)xAResource;
    DAOUtils.close(conn);
    connMap.remove(conn.getName());
    return true;

  }


  public boolean enlistResource(XAResource xAResource) {
    if (!(xAResource instanceof TransConnection)) {
      throw new UnsupportedOperationException();
    }
    try {
      TransConnection conn = (TransConnection)xAResource;
      conn.setAutoCommit(false);
      connMap.put(conn.getName(), conn);
      return true;
    }
    catch (SQLException se) {
      se.printStackTrace();
      return false; 
    }
  }

  
 /**
  * get a resource by name
  */
  public Object getResource(String name) {
    if (connMap.containsKey(name)) {
      return connMap.get(name);
    }
    else {
      return null; 
    }
  }
  
 /**
  * get the status of this transaction
  */
  public int getStatus() {
    return status;
  }
  
 /**
  * not supported
  */
  public void registerSynchronization(Synchronization synchronization) {
    throw new UnsupportedOperationException();
  }
  
 /**
  * rollback the connections in this transaction
  */
  public void rollback() {
    status = Status.STATUS_ROLLING_BACK;
    Iterator iter = connMap.values().iterator();
    while (iter.hasNext()) {
      TransConnection conn = (TransConnection)iter.next();
      try {
        if (log.isDebugEnabled()) {
          log.debug("rollback connection " + conn); 
        }
        conn.doRollback(null);

        if (conn.isCloseFlagged()) {
          if (log.isDebugEnabled()) {
            log.debug("close flagged, so closing connection"); 
          }
          conn.doClose();
          iter.remove();
        }
      }
      catch (SQLException se) {
        se.printStackTrace(); 
      }
    }
    status = Status.STATUS_ROLLEDBACK;
  }
  
 /**
  * flag that a rollback is required
  */
  public void setRollbackOnly() {
    status = Status.STATUS_MARKED_ROLLBACK;    
  } 
}
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