/*
* 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 java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import weka.core.Instance;
import weka.core.Instances;
import java.io.InputStream;
import java.io.FileInputStream;
import java.io.InputStreamReader;
/**
* Reads a source that is in arff text format.
*
* @author Mark Hall (mhall@cs.waikato.ac.nz)
* @version $Revision: 1.1.1.1 $
* @see Loader
*/
public class ArffLoader extends AbstractLoader
implements BatchLoader, IncrementalLoader {
/**
* Holds the determined structure (header) of the data set.
*/
//@ protected depends: model_structureDetermined -> m_structure;
//@ protected represents: model_structureDetermined <- (m_structure != null);
protected transient Instances m_structure = null;
protected String m_File =
(new File(System.getProperty("user.dir"))).getName();
/**
* The reader for the source file.
*/
private transient Reader m_sourceReader = null;
/**
* Resets the Loader ready to read a new data set
*/
public void reset() {
m_structure = null;
// m_sourceReader = null;
setRetrieval(NONE);
}
/**
* 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");
}
}
/**
* get the File specified as the source
*
* @return the source file
*/
public File getFile() {
return new File(m_File);
}
/**
* sets the source File
*
* @param file the source file
* @exception IOException if an error occurs
*/
public void setFile(File file) throws IOException {
m_File = file.getName();
setSource(file);
}
/**
* Resets the Loader object and sets the source of the data set to be
* the supplied InputStream.
*
* @param in the source InputStream.
* @exception IOException always thrown.
*/
public void setSource(InputStream in) throws IOException {
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
* @exception 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.");
}
}
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
* @exception 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));
return m_structure;
}
/**
* 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_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)) {
return null;
}
Instance current = m_structure.instance(0);
m_structure.delete(0);
return current;
}
/**
* 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 {
ArffLoader atf = new ArffLoader();
atf.setSource(inputfile);
System.out.println(atf.getStructure());
Instance temp;
do {
temp = atf.getNextInstance();
if (temp != null) {
System.out.println(temp);
}
} while (temp != null);
} catch (Exception ex) {
ex.printStackTrace();
}
} else {
System.err.println("Usage:\n\tArffLoader <file.arff>\n");
}
}
}