arffloader.java

代码是一个分类器的实现,其中使用了部分weka的源代码。可以将项目导入eclipse运行

/*
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 2 of the License, or
 *    (at your option) any later version.
 *
 *    This program 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 General Public License
 *    along with this program; if not, write to the Free Software
 *    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/*
 *    ArffLoader.java
 *    Copyright (C) 2000 Mark Hall
 *
 */

package weka.core.converters;

import weka.core.Instance;
import weka.core.Instances;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.URL;
import java.util.zip.GZIPInputStream;

/**
 <!-- globalinfo-start -->
 * Reads a source that is in arff (attribute relation file format) format.
 * <p/>
 <!-- globalinfo-end -->
 *
 * @author Mark Hall ([e-mail])
 * @version $Revision: 1.15 $
 * @see Loader
 */
public class ArffLoader 
  extends AbstractFileLoader 
  implements BatchConverter, IncrementalConverter, URLSourcedLoader {

  /** for serialization */
  static final long serialVersionUID = 2726929550544048587L;
  
  /** the file extension */
  public static String FILE_EXTENSION = Instances.FILE_EXTENSION;

  /** the extension for compressed files */
  public static String FILE_EXTENSION_COMPRESSED = FILE_EXTENSION + ".gz";

  /** the url */
  protected String m_URL = "http://";

  /**
   * The reader for the source file.
   */
  private transient Reader m_sourceReader = null;

  /**
   * Returns a string describing this Loader
   * @return a description of the Loader suitable for
   * displaying in the explorer/experimenter gui
   */
  public String globalInfo() {
    return "Reads a source that is in arff (attribute relation file format) "
      +"format. ";
  }

  /**
   * Get the file extension used for arff files
   *
   * @return the file extension
   */
  public String getFileExtension() {
    return FILE_EXTENSION;
  }

  /**
   * Gets all the file extensions used for this type of file
   *
   * @return the file extensions
   */
  public String[] getFileExtensions() {
    return new String[]{FILE_EXTENSION, FILE_EXTENSION_COMPRESSED};
  }

  /**
   * Returns a description of the file type.
   *
   * @return a short file description
   */
  public String getFileDescription() {
    return "Arff data files";
  }

  /**
   * Resets the Loader ready to read a new data set
   * 
   * @throws IOException if something goes wrong
   */
  public void reset() throws IOException {
    m_structure = null;
    setRetrieval(NONE);
    
    if (m_File != null && (new File(m_File)).isFile()) {
      setFile(new File(m_File));
    } else if (m_URL != null & !m_URL.equals("http://")) {
      setURL(m_URL);
    }
  }

  /**
   * Resets the Loader object and sets the source of the data set to be 
   * the supplied url.
   *
   * @param url the source url.
   * @throws IOException if an error occurs
   */
  public void setSource(URL url) throws IOException {
    m_structure = null;
    setRetrieval(NONE);
    
    setSource(url.openStream());

    m_URL = url.toString();
  }
  

  /**
   * get the File specified as the source
   *
   * @return the source file
   */
  public File retrieveFile() {
    return new File(m_File);
  }

  /**
   * sets the source File
   *
   * @param file the source file
   * @throws IOException if an error occurs
   */
  public void setFile(File file) throws IOException {
    m_File = file.getAbsolutePath();
    setSource(file);
  }

  /**
   * Resets the Loader object and sets the source of the data set to be 
   * the supplied File object.
   *
   * @param file 		the source file.
   * @throws IOException 	if an error occurs
   */
  public void setSource(File file) throws IOException {
    m_structure    = null;
    
    setRetrieval(NONE);

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

    try {
      if (file.getName().endsWith(FILE_EXTENSION_COMPRESSED))
	setSource(new GZIPInputStream(new FileInputStream(file)));
      else
	setSource(new FileInputStream(file));
    }
    catch (FileNotFoundException ex) {
      throw new IOException("File not found");
    }
    
    m_sourceFile = file;
    m_File       = file.getAbsolutePath();
  }

  /**
   * Set the url to load from
   *
   * @param url the url to load from
   * @throws IOException if the url can't be set.
   */
  public void setURL(String url) throws IOException {
    m_URL = url;
    setSource(new URL(url));
  }

  /**
   * Return the current url
   *
   * @return the current url
   */
  public String retrieveURL() {
    return m_URL;
  }

  /**
   * Resets the Loader object and sets the source of the data set to be 
   * the supplied InputStream.
   *
   * @param in the source InputStream.
   * @throws IOException always thrown.
   */
  public void setSource(InputStream in) throws IOException {
    // m_File = null;
    m_File = (new File(System.getProperty("user.dir"))).
      getAbsolutePath();
    m_URL = "http://";

    m_sourceReader = new BufferedReader(new InputStreamReader(in));
  }

  /**
   * 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
   * @throws IOException if an error occurs
   */
  public Instances getStructure() throws IOException {

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

    if (m_structure == null) {
      try {
	m_structure = new Instances(m_sourceReader, 1);
      } catch (Exception ex) {
	throw new IOException("Unable to determine structure as arff (Reason: " + ex.toString() + ").");
      }
    }

    return new Instances(m_structure, 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
   * @throws IOException if there is no source or parsing fails
   */
  public Instances getDataSet() throws IOException {

    if (m_sourceReader == null) {
      throw new IOException("No source has been specified");
    }
    if (getRetrieval() == INCREMENTAL) {
      throw new IOException("Cannot mix getting Instances in both incremental and batch modes");
    }
    setRetrieval(BATCH);
    if (m_structure == null) {
      getStructure();
    }

    // Read all instances
    // XXX This is inefficient because readInstance creates a new 
    // StringTokenizer each time: This will be fixed once all arff reading
    // is moved out of Instances and into this Loader.
    while (m_structure.readInstance(m_sourceReader));
    
    Instances readIn = new Instances(m_structure);
    /*if (m_File != null) {
	File temp = new File(m_File);
	if (temp.exists()) {
	  setSource(temp);
	}
    }*/
    
    return readIn;
  }

  /**
   * 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
   * @throws IOException if there is an error during parsing
   */
  public Instance getNextInstance() throws IOException {

    if (m_structure == null) {
      getStructure();
    }
    if (getRetrieval() == BATCH) {
      throw new IOException("Cannot mix getting Instances in both incremental and batch modes");
    }
    setRetrieval(INCREMENTAL);

    if (!m_structure.readInstance(m_sourceReader)) {
      // try to reset the loader if the source is a file
      /*if (m_File != null) {
	File temp = new File(m_File);
	if (temp.exists()) {
	  setSource(temp);
	}
      }*/
      return null;
    }
   
    Instance current = m_structure.instance(0);
    m_structure.delete(0);
    if (current == null) {
      try {
        reset();
      } catch (Exception ex) {
        ex.printStackTrace();
      }
    }
    return current;
  }

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