org.briljantframework.data.reader.CsvEntryReader.java Source code

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Here is the source code for org.briljantframework.data.reader.CsvEntryReader.java

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/**
 * The MIT License (MIT)
 *
 * Copyright (c) 2016 Isak Karlsson
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy of this software and
 * associated documentation files (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge, publish, distribute,
 * sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all copies or
 * substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT
 * NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
 * DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
package org.briljantframework.data.reader;

import java.io.BufferedReader;
import java.io.Reader;
import java.time.LocalDate;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
import java.util.NoSuchElementException;

import org.apache.commons.lang3.math.NumberUtils;
import org.briljantframework.data.resolver.Resolve;
import org.briljantframework.data.resolver.Resolver;

import com.univocity.parsers.csv.CsvParser;
import com.univocity.parsers.csv.CsvParserSettings;

/**
 * Reads a delimited file and produces one {@linkplain DataEntry data entry} for each line in the
 * file.
 *
 * @author Isak Karlsson
 * @see org.briljantframework.data.parser.CsvParser Read a data frame from a Csv-file
 */
public class CsvEntryReader implements EntryReader {

    private final CsvParser csvParser;
    private final String missingValue;
    private String[] current = null;
    private List<Class<?>> types = null;

    public CsvEntryReader(CsvParserSettings settings, Reader reader, String missingValue) {
        csvParser = new CsvParser(settings);
        csvParser.beginParsing(new BufferedReader(reader));
        this.missingValue = missingValue;
    }

    @Override
    public List<Class<?>> getTypes() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        if (types == null) {
            types = new ArrayList<>();
            for (String repr : current) {
                if (repr != null) {
                    repr = repr.trim();
                }
                if (repr == null || repr.equals(missingValue)) {
                    types.add(Object.class);
                } else if (NumberUtils.isNumber(repr)) {
                    Number number = NumberUtils.createNumber(repr);
                    types.add(number.getClass());
                } else {
                    // Finally, try to resolve the value using the registered resolvers
                    Resolver<?> resolver = null;
                    Object data;
                    if ((resolver = Resolve.find(LocalDate.class)) != null) {
                        data = resolver.resolve(repr);
                    } else {
                        data = null;
                    }
                    if (data == null) {
                        types.add(Object.class);
                    } else {
                        types.add(data.getClass());
                    }
                }
            }
        }
        return Collections.unmodifiableList(types);
    }

    @Override
    public DataEntry next() {
        if (!hasNext()) {
            throw new NoSuchElementException();
        }
        DataEntry entry = new StringDataEntry(current, missingValue);
        current = null;
        return entry;
    }

    @Override
    public boolean hasNext() {
        if (current == null) {
            current = csvParser.parseNext();
        }
        return current != null;
    }
}