Class DiskValues

basex-core/src/main/java/org/basex/index/value/DiskValues.java:27–477

This class provides access to attribute values and text contents stored on disk. The data structure is described in the DiskValuesBuilder class. @author BaseX Team, BSD License @author Christian Gruen

 * @author Christian Gruen
 */
public class DiskValues extends ValueIndex {
  /** ID references. */
  final DataAccess idxr;
  /** ID lists. */
  final DataAccess idxl;
  /** Cached index entries: mapping between keys and index entries. */
  final IndexCache cache = new IndexCache();
  /** Cached texts: mapping between key positions in the reference file, and the indexed texts. */
  final IntObjectMap<byte[]> ctext = new IntObjectMap<>();
  /** Number of current index entries. */
  final AtomicInteger size = new AtomicInteger();

  /** Synchronization object. */
  private final Object monitor = new Object();

  /**
   * Constructor, initializing the index structure.
   * @param data data reference
   * @param type index type
   * @throws IOException I/O Exception
   */
  public DiskValues(final Data data, final IndexType type) throws IOException {
    this(data, type, fileSuffix(type));
  }

  /**
   * Constructor, initializing the index structure.
   * @param data data reference
   * @param type index type
   * @param prefix file prefix
   * @throws IOException I/O Exception
   */
  DiskValues(final Data data, final IndexType type, final String prefix) throws IOException {
    super(data, type);
    idxl = new DataAccess(data.meta.dbFile(prefix + 'l'));
    idxr = new DataAccess(data.meta.dbFile(prefix + 'r'));
    size.set(idxl.read4());
  }

  @Override
  public final byte[] info(final MainOptions options) {
    final TokenBuilder tb = new TokenBuilder();
    tb.add(LI_STRUCTURE).add(SORTED_LIST).add(NL);
    tb.add(LI_NAMES).add(data.meta.names(type)).add(NL);

    final IndexStats stats = new IndexStats(options.get(MainOptions.MAXSTAT));
    synchronized(monitor) {
      final long l = idxl.length() + idxr.length();
      tb.add(LI_SIZE).add(Performance.formatHuman(l)).add(NL);
      final int entries = size();
      for(int index = 0; index < entries; index++) {
        final long pos = idxr.read5(index * 5L);
        final int count = idxl.readNum(pos);
        if(stats.adding(count)) stats.add(key(idxl.readNum()), count);
      }
    }
    stats.print(tb);
    return tb.finish();