/
AutoReadingSource.java
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/
AutoReadingSource.java
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/*
* Copyright (c) 2002-2018 "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 org.neo4j.csv.reader;
import java.io.IOException;
/**
* In a scenario where there's one thread, or perhaps a {@link ThreadAheadReadable} doing both the
* reading and parsing one {@link BufferedCharSeeker} is used over a stream of chunks, where the next
* chunk seamlessly transitions into the next, this class comes in handy. It uses a {@link CharReadable}
* and {@link SectionedCharBuffer} to do this.
*/
public class AutoReadingSource implements Source
{
private final CharReadable reader;
private SectionedCharBuffer charBuffer;
public AutoReadingSource( CharReadable reader, int bufferSize )
{
this( reader, new SectionedCharBuffer( bufferSize ) );
}
public AutoReadingSource( CharReadable reader, SectionedCharBuffer charBuffer )
{
this.reader = reader;
this.charBuffer = charBuffer;
}
@Override
public Chunk nextChunk( int seekStartPos ) throws IOException
{
charBuffer = reader.read( charBuffer, seekStartPos == -1 ? charBuffer.pivot() : seekStartPos );
return new Chunk()
{
@Override
public int startPosition()
{
return charBuffer.pivot();
}
@Override
public String sourceDescription()
{
return reader.sourceDescription();
}
@Override
public int backPosition()
{
return charBuffer.back();
}
@Override
public int length()
{
return charBuffer.available();
}
@Override
public int maxFieldSize()
{
return charBuffer.pivot();
}
@Override
public char[] data()
{
return charBuffer.array();
}
};
}
@Override
public void close() throws IOException
{
reader.close();
}
}