serializedobject.java

一个数据挖掘系统的源码

/**
 *   
 *   AgentAcademy - an open source Data Mining framework for
 *   training intelligent agents
 *
 *   Copyright (C)   2001-2003 AA Consortium.
 *
 *   This library is open source 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 2.0 of the License, or (at your option) any later 
 *   version.
 *
 *   This library 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 General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public
 *   License along with this library; if not, write to the Free 
 *   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, 
 *   MA  02111-1307 USA
 * 
 */

package org.agentacademy.modules.dataminer.core;

/**
 * <p>Title: The Data Miner prototype</p>
 * <p>Description: A prototype for the DataMiner (DM), the Agent Academy (AA) module responsible for performing data mining on the contents of the Agent Use Repository (AUR). The extracted knowledge is to be sent back to the AUR in the form of a PMML document.</p>
 * <p>Copyright: Copyright (c) 2002</p>
 * <p>Company: CERTH</p>
 * @author asymeon
 * @version 0.3
 */

import java.io.*;
import java.util.zip.*;

/**
 * Class for storing an object in serialized form in memory. It can be used
 * to make deep copies of objects, and also allows compression to conserve
 * memory. <p>
 *
 */
public class SerializedObject implements Serializable {

  /** The array storing the object. */
  private byte[] m_storedObjectArray;

  /** Whether or not the object is compressed. */
  private boolean m_isCompressed;

  /**
   * Creates a new serialized object (without compression).
   *
   * @param toStore the object to store
   * @param compress whether or not to use compression
   * @exception Exception if the object couldn't be serialized
   */
  public SerializedObject(Object toStore) throws Exception {

    this(toStore, false);
  }

  /**
   * Creates a new serialized object.
   *
   * @param toStore the object to store
   * @param compress whether or not to use compression
   * @exception Exception if the object couldn't be serialized
   */
  public SerializedObject(Object toStore, boolean compress) throws Exception {

    ByteArrayOutputStream ostream = new ByteArrayOutputStream();
    OutputStream os = ostream;
    ObjectOutputStream p;
    if (!compress)
      p = new ObjectOutputStream(new BufferedOutputStream(os));
    else
      p = new ObjectOutputStream(new BufferedOutputStream(new GZIPOutputStream(os)));
    p.writeObject(toStore);
    p.flush();
    p.close(); // used to be ostream.close() !
    m_storedObjectArray = ostream.toByteArray();

    m_isCompressed = compress;
  }

  /*
   * Checks to see whether this object is equal to another.
   *
   * @param compareTo the object to compare to
   * @return whether or not the objects are equal
   */
  public final boolean equals(Object compareTo) {

    if (compareTo == null) return false;
    if (!compareTo.getClass().equals(this.getClass())) return false;
    byte[] compareArray = ((SerializedObject)compareTo).m_storedObjectArray;
    if (compareArray.length != m_storedObjectArray.length) return false;
    for (int i=0; i<compareArray.length; i++) {
      if (compareArray[i] != m_storedObjectArray[i]) return false;
    }
    return true;
  }

  /**
   * Returns a hashcode for this object.
   *
   * @return the hashcode
   */
  public int hashCode() {

    return m_storedObjectArray.length;
  }

  /**
   * Returns a serialized object.
   *
   * @return the restored object
   * @exception Exception if the object couldn't be restored
   */
  public Object getObject() {

    try {
      ByteArrayInputStream istream = new ByteArrayInputStream(m_storedObjectArray);
      ObjectInputStream p;
      if (!m_isCompressed)
	p = new ObjectInputStream(new BufferedInputStream(istream));
      else
	p = new ObjectInputStream(new BufferedInputStream(new GZIPInputStream(istream)));
      Object toReturn = p.readObject();
      istream.close();
      return toReturn;
    } catch (Exception e) {
      e.printStackTrace();
      return null;
    }
  }
}