/*
* Encog(tm) Core v3.3 - Java Version
* http://www.heatonresearch.com/encog/
* https://github.com/encog/encog-java-core
* Copyright 2008-2014 Heaton Research, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* For more information on Heaton Research copyrights, licenses
* and trademarks visit:
* http://www.heatonresearch.com/copyright
*/
package org.encog.ml.data.versatile.sources;
import java.io.File;
import java.util.HashMap;
import java.util.Map;
import org.encog.EncogError;
import org.encog.util.csv.CSVFormat;
import org.encog.util.csv.ReadCSV;
/**
* Allow a CSV file to serve as a source for the versatile data source.
*/
public class CSVDataSource implements VersatileDataSource {
/**
* The CSV reader.
*/
private ReadCSV reader;
/**
* The file to read.
*/
private final File file;
/**
* True, if the file has headers.
*/
private final boolean headers;
/**
* The CSV format of the file.
*/
private final CSVFormat format;
/**
* The index values for each header, if we have headers.
*/
private final Map<String,Integer> headerIndex = new HashMap<String,Integer>();
/**
* Construct a CSV source from a filename. The format parameter specifies
* the separator character to use, as well as the number format.
*
* @param filename
* The filename.
* @param headers
* The headers.
* @param delim
* The delimiter.
*/
public CSVDataSource(final File file, final boolean headers,
final char delim) {
this.format = new CSVFormat(CSVFormat.getDecimalCharacter(),
delim);
this.headers = headers;
this.file = file;
}
/**
* Construct a CSV source from a filename. Allows a delimiter character to
* be specified.
*
* @param filename
* The filename.
* @param headers
* The headers.
* @param format
* The format.
*/
public CSVDataSource(final File file, final boolean headers,
final CSVFormat format) {
this.file = file;
this.headers = headers;
this.format = format;
}
/**
* {@inheritDoc}
*/
@Override
public String[] readLine() {
if( this.reader==null) {
throw new EncogError("Please call rewind before reading the file.");
}
if( this.reader.next() ) {
int len = this.reader.getColumnCount();
String[] result = new String[len];
for(int i=0;i<result.length;i++) {
result[i]=this.reader.get(i);
}
return result;
} else {
reader.close();
return null;
}
}
/**
* {@inheritDoc}
*/
@Override
public void rewind() {
this.reader = new ReadCSV(this.file,this.headers,this.format);
if( this.headerIndex.size()==0 ) {
for(int i=0;i<this.reader.getColumnNames().size();i++) {
this.headerIndex.put(this.reader.getColumnNames().get(i), i);
}
}
}
/**
* {@inheritDoc}
*/
@Override
public int columnIndex(String name) {
String name2 = name.toLowerCase();
if(!this.headerIndex.containsKey(name2)) {
return -1;
}
return this.headerIndex.get(name2);
}
}