datastream.java

Boosting算法软件包

package jboost.tokenizer;

import java.io.IOException;

import jboost.examples.ExampleDescription;

/** This abstract class defines the ability to read a given format of 
 *  data. For example, jboost format, UCI format, Email, from a JDBC source etc.
 *  Including the schema or specification of the data.
 *
 *  @author Nigel Duffy
 *  @version $Header: /cvsroot/jboost/jboost/src/jboost/tokenizer/DataStream.java,v 1.2 2007/10/23 23:52:26 aarvey Exp $
*/
public abstract class DataStream {
  
    public static String WEIGHT_ATTR= "weight";
    public static String ID_ATTR = "id";
    public static String LABELS_ATTR= "labels";
  
   /** Creates the textual form of a single specific example    
    *  Not yet implemented.  
    *  
    *  @param o The object to transform into an example                                 */
    public abstract String[] getExampleText(Object o) throws ParseException;


   /** Returns the line number of the current example in the data source.               */
    public abstract long getLineNumber();

   /** Creates out a string containing the information necessary to 
    *  read the datafile.								*/
    public abstract String toString();

   /** Retreives the data specification in a standard internal form.			*/
    public abstract ExampleDescription getExampleDescription();

   /** Gets an array of attributes in a standard textual form that can then be 
    *  transformed into an example by ExampleStream.					*/
    public abstract String[] getExampleText() throws ParseException;

   /** Using the same example description use this DataStream on a different data 
    *  source.										*/
    public abstract void reset(String data) throws IOException;

    /** reopen the same data source */
    public void reset() throws IOException {
	reset(data);
    }

   /** Constructor									
    *  @param spec The name of the specification file.
    *  @param data The name of the data file.						*/
    public DataStream(String spec, String data) 
	throws IOException,SpecFileException
    {
	this.data = data;
    }
    
   /** Constructor								
    *  @param isFile Is the second parameter a specification or a name of a file?.
    *  @param stem A string containing the specification or the stem for the data files.	*/
    public DataStream(boolean isFile, String stem) throws IOException,SpecFileException {}

   /** Default constructor.								*/
    public DataStream() throws IOException,SpecFileException {}

//------------------------------- Accessor Methods ------------------------------------//


//------------------------------- Protected Members -----------------------------------//

    /** Information about the example that is used by {@link
	jboost.tokenizer.ExampleStream} to transform the field strings
	into the jboost internal represantation */
    protected ExampleDescription ed;
    /** Number of attributes in a single example */
    protected int noAttr=0;
    /** Maximal number of bad attributes allowed in a single good example */
    protected int maxBadAtt;
    /** Maximal number of missing attributes allowed in a single good
        example */
    protected int maxMisAtt;
    /** Maximal number of bad examples allowed in a single stream */
    protected int maxBadExa;
    /** Counter for number of bad examples seen so far */
    protected int numBadExa=0;



//------------------------------- Private Members -------------------------------------//

    private String data;

//------------------------------- Test Code -------------------------------------------//\
}