LinedFileDataProvider.java

package proj.zoie.perf.indexing;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.nio.charset.Charset;

import org.apache.log4j.Logger;

import proj.zoie.api.DataConsumer.DataEvent;
import proj.zoie.impl.indexing.StreamDataProvider;
import proj.zoie.impl.indexing.ZoieConfig;
import proj.zoie.perf.client.ZoiePerfVersion;

public class LinedFileDataProvider extends StreamDataProvider<String> {

  private static final Logger logger = Logger.getLogger(LinedFileDataProvider.class);

  private final File _file;
  private long _startingOffset;
  private long _offset;
  private int _count = 0;

  private BufferedReader _rad;

  public LinedFileDataProvider(File file, long startingOffset) {
    super(ZoiePerfVersion.COMPARATOR);
    _file = file;
    _rad = null;
    _startingOffset = startingOffset;
  }

  @Override
  public DataEvent<String> next() {
    DataEvent<String> event = null;
    if (_rad != null) {
      try {
        String line = _rad.readLine();
        if (line == null) return null;

        String version = ZoiePerfVersion.toString(_count, _offset);
        _offset += line.length();
        _count++;

        event = new DataEvent<String>(line, version);
      } catch (IOException ioe) {
        logger.error(ioe.getMessage(), ioe);
      }
    }
    return event;
  }

  public int getCount() {
    return _count;
  }

  @Override
  public void setStartingOffset(String version) {
    ZoiePerfVersion perfVersion = ZoiePerfVersion.fromString(version);
    _startingOffset = perfVersion.offsetVersion;
  }

  @Override
  public void reset() {

    try {
      if (_rad != null) {
        _rad.close();
      }
      _rad = new BufferedReader(new InputStreamReader(new FileInputStream(_file),
          Charset.forName("UTF-8")));
      _offset = _startingOffset;
      for (long i = 0; i < _offset; ++i) {
        _rad.read();
      }
      _count = 0;
    } catch (IOException e) {
      logger.error(e.getMessage(), e);
    }
  }

  @Override
  public void start() {
    super.start();
    reset();
  }

  @Override
  public void stop() {
    try {
      super.stop();

    } finally {
      try {
        if (_rad != null) {
          _rad.close();
        }
      } catch (IOException ioe) {
        logger.error(ioe.getMessage(), ioe);
      } finally {
        _rad = null;
      }
    }
  }
}