GribFileAccess.java

package com.meteogroup.grib2geotiff.grib;

import ucar.grib.grib2.Grib2Data;
import ucar.grib.grib2.Grib2IdentificationSection;
import ucar.grib.grib2.Grib2Input;
import ucar.grib.grib2.Grib2Record;
import ucar.unidata.io.RandomAccessFile;

import java.io.File;
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

/**
 * Created by danielt on 14.09.15.
 */
public class GribFileAccess {

  private File inputDirectory;

  private static final Logger LOGGER = Logger.getLogger(GribFileAccess.class.getName());

  /**
   * @param inputDirectory
   */
  public void setInputDirectory(File inputDirectory) {
    this.inputDirectory = inputDirectory;
  }

  /**
   * @param gfsFile
   * @param record
   * @return
   * @throws IOException
   */
  public float[] getGfsRecordData(RandomAccessFile gfsFile, Grib2Record record) throws IOException {
    Grib2Data gd = new Grib2Data(gfsFile);
    Grib2IdentificationSection id = record.getId();
    return gd.getData(record.getGdsOffset(), record.getPdsOffset(), id.getRefTime());
  }

  /**
   * @return
   * @throws Exception
   */
  public List<RandomAccessFile> getRafFiles() throws Exception {
    LOGGER.info("start scanning folder " + inputDirectory.getAbsolutePath());
    List<RandomAccessFile> validRafFiles = new ArrayList<RandomAccessFile>();
    File[] files = inputDirectory.listFiles();
    if (files == null || files.length == 0) {
      return validRafFiles;
    }

    for (File file : files) {
      RandomAccessFile validRaf = getValidGribfile(file);

      if (validRaf != null) {
        LOGGER.info("use " + file.getAbsolutePath());
        validRafFiles.add(validRaf);
      } else {
        LOGGER.info("skip " + file.getAbsolutePath());
      }
    }
    return validRafFiles;
  }

  /**
   * @param file
   * @return
   * @throws Exception
   */
  private RandomAccessFile getValidGribfile(File file) throws Exception {
    if (!file.exists()
        || file.isDirectory()
        || file.getName().endsWith(".aux.xml")) {
      return null;
    }
    RandomAccessFile raf = new RandomAccessFile(file.getAbsolutePath(), "r");
    raf.order(RandomAccessFile.BIG_ENDIAN);

    if (Grib2Input.isValidFile(raf)) {
      return raf;
    } else {
      return null;
    }

  }

  /**
   * @param gfsFile
   * @return
   * @throws Exception
   */
  public List<Grib2Record> getRecords(RandomAccessFile gfsFile) throws Exception {
    Grib2Input g2i = new Grib2Input(gfsFile);
    g2i.scan(false, false);
    return g2i.getRecords();
  }

}