CharSeekers.java

/**
 * Copyright (c) 2002-2014 "Neo Technology,"
 * Network Engine for Objects in Lund AB [http://neotechnology.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j 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 3 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, see <http://www.gnu.org/licenses/>.
 */
package com.ldbc.driver.csv.charseeker;

import java.io.FileNotFoundException;
import java.io.FileReader;

import static com.ldbc.driver.csv.charseeker.BufferedCharSeeker.DEFAULT_BUFFER_SIZE;

/**
 * Factory for common {@link CharSeeker} implementations.
 */
public class CharSeekers {
    /**
     * Instantiates a {@link BufferedCharSeeker} with optional {@link ThreadAheadReadable read-ahead} capability.
     *
     * @param reader             the {@link CharReadable} which is the source of data, f.ex. a {@link FileReader}.
     * @param bufferSize         buffer size of the seeker and, if enabled, the read-ahead thread.
     * @param readAhead          whether or not to start a {@link ThreadAheadReadable read-ahead thread}
     *                           which strives towards always keeping one buffer worth of data read and available from I/O when it's
     *                           time for the {@link BufferedCharSeeker} to read more data.
     * @param quotationCharacter character to interpret quotation character.
     * @return a {@link CharSeeker} with optional {@link ThreadAheadReadable read-ahead} capability.
     */
    public static CharSeeker charSeeker(CharReadable reader, int bufferSize, boolean readAhead, char quotationCharacter) {
        if (readAhead) {   // Thread that always has one buffer read ahead
            reader = ThreadAheadReadable.threadAhead(reader, bufferSize);
        }

        // Give the reader to the char seeker
        return new BufferedCharSeeker(reader, bufferSize, quotationCharacter);
    }

    /**
     * Instantiates a default {@link CharSeeker} capable of reading data in the specified {@code file}.
     *
     * @return {@link CharSeeker} reading and parsing data from {@code file}.
     * @throws FileNotFoundException if the specified {@code file} doesn't exist.
     */
    public static CharSeeker charSeeker(CharReadable reader, char quotationCharacter) throws FileNotFoundException {
        return charSeeker(reader, DEFAULT_BUFFER_SIZE, true, quotationCharacter);
    }
}