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RankSys module, providing utilities for reading and writing into different formats of preference data, recommendations, etc.
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/*
* Copyright (C) 2016 RankSys http://ranksys.org
*
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/.
*/
package org.ranksys.formats.feature;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.stream.Stream;
import org.jooq.lambda.tuple.Tuple;
import org.jooq.lambda.tuple.Tuple3;
import org.ranksys.formats.parsing.Parser;
/**
* Reads a file of tab-separated item-feat-value triples, one per line.
*
* @author Saúl Vargas ([email protected])
*/
public class SimpleFeaturesReader implements FeaturesReader {
/**
* Returns and instance of this class.
*
* @param item type
* @param feat type
* @return an instance of SimpleFeaturesReader
*/
public static SimpleFeaturesReader get() {
return new SimpleFeaturesReader();
}
private SimpleFeaturesReader() {
}
@Override
public Stream> read(String in, Parser ip, Parser fp) throws IOException {
return read(new FileInputStream(in), ip, fp);
}
@Override
public Stream> read(InputStream in, Parser ip, Parser fp) throws IOException {
return new BufferedReader(new InputStreamReader(in)).lines().map(line -> {
String[] tokens = line.split("\t", 3);
I item = ip.parse(tokens[0]);
F feat = fp.parse(tokens[1]);
return Tuple.tuple(item, feat, 1.0);
});
}
}