serializedinstancesloader.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.converters;

/**
 * <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.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.ObjectInputStream;
import org.agentacademy.modules.dataminer.core.Instance;
import org.agentacademy.modules.dataminer.core.Instances;

/**
 * Reads a source that contains serialized Instances.
 *
 * @see Loader
 */
public class SerializedInstancesLoader extends AbstractLoader {

  /** Holds the structure (header) of the data set. */
  protected Instances m_Dataset = null;

  /** The current index position for incremental reading */
  protected int m_IncrementalIndex = 0;

  /** Resets the Loader ready to read a new data set */
  public void reset() {

    m_Dataset = null;
    m_IncrementalIndex = 0;
  }

  /**
   * Resets the Loader object and sets the source of the data set to be
   * the supplied File object.
   *
   * @param file the source file.
   * @exception IOException if an error occurs
   */
  public void setSource(File file) throws IOException {

    reset();

    if (file == null) {
      throw new IOException("Source file object is null!");
    }

    try {
      setSource(new FileInputStream(file));
    } catch (FileNotFoundException ex) {
      throw new IOException("File not found");
    }
  }

  /**
   * Resets the Loader object and sets the source of the data set to be
   * the supplied InputStream.
   *
   * @param in the source InputStream.
   * @exception IOException if there is a problem with IO
   */
  public void setSource(InputStream in) throws IOException {

    ObjectInputStream oi = new ObjectInputStream(new BufferedInputStream(in));
    try {
      m_Dataset = (Instances)oi.readObject();
    } catch (ClassNotFoundException ex) {
      throw new IOException("Could not deserialize instances from this source.");
    }
  }

  /**
   * Determines and returns (if possible) the structure (internally the
   * header) of the data set as an empty set of instances.
   *
   * @return the structure of the data set as an empty set of Instances
   * @exception IOException if an error occurs
   */
  public Instances getStructure() throws IOException {

    if (m_Dataset == null) {
      throw new IOException("No source has been specified");
    }

    // We could cache a structure-only if getStructure is likely to be called
    // many times.
    return new Instances(m_Dataset, 0);
  }

  /**
   * Return the full data set. If the structure hasn't yet been determined
   * by a call to getStructure then method should do so before processing
   * the rest of the data set.
   *
   * @return the structure of the data set as an empty set of Instances
   * @exception IOException if there is no source or parsing fails
   */
  public Instances getDataSet() throws IOException {

    if (m_Dataset == null) {
      throw new IOException("No source has been specified");
    }

    return m_Dataset;
  }

  /**
   * Read the data set incrementally---get the next instance in the data
   * set or returns null if there are no
   * more instances to get. If the structure hasn't yet been
   * determined by a call to getStructure then method should do so before
   * returning the next instance in the data set.
   *
   * @return the next instance in the data set as an Instance object or null
   * if there are no more instances to be read
   * @exception IOException if there is an error during parsing
   */
  public Instance getNextInstance() throws IOException {

    if (m_Dataset == null) {
      throw new IOException("No source has been specified");
    }

    // We have to fake this method, since we can only deserialize an entire
    // dataset at a time.
    if (m_IncrementalIndex == m_Dataset.numInstances()) {
      return null;
    }

    return m_Dataset.instance(m_IncrementalIndex++);
  }

  /**
   * Main method.
   *
   * @param args should contain the name of an input file.
   */
  public static void main(String [] args) {

    if (args.length > 0) {
      File inputfile;
      inputfile = new File(args[0]);
      try {
	SerializedInstancesLoader lo = new SerializedInstancesLoader();
	lo.setSource(inputfile);
	System.out.println(lo.getStructure());
	Instance temp;
	do {
	  temp = lo.getNextInstance();
	  if (temp != null) {
	    System.out.println(temp);
	  }
	} while (temp != null);
      } catch (Exception ex) {
	ex.printStackTrace();
      }
    } else {
      System.err.println("Usage:\n\tSerializedInstancesLoader <file>\n");
    }
  }
}