Class FuzzyRowFilter

src/FuzzyRowFilter.java:69–184

FuzzyRowFilter is a server-side fast-forward filter that allows skipping whole range of rows when scanning. The feature is available in HBase 0.94.5 and above. It takes two byte array to match a rowkey, one to hold the fixed value and one to hold a mask indicating which bytes of the rowkey must

 * @since 1.7
 */
public final class FuzzyRowFilter extends ScanFilter {

  private static final byte[] NAME =
      Bytes.UTF8("org.apache.hadoop.hbase.filter.FuzzyRowFilter");

  private final Collection<FuzzyFilterPair> filter_pairs;

  /**
   * Holds a pair of (row_key,fuzzy_mask) to use with {@link FuzzyRowFilter}
   */
  public static class FuzzyFilterPair {
    private final byte[] row_key;
    private final byte[] fuzzy_mask;

    /** 
     * Default Ctor
     * @param row_key The row key to use for matching
     * @param fuzzy_mask The row key mask to determine which of the bytes in
     * {@code row_key} should be matched.
     * @throws IllegalArgumentException if the keys are not the same length
     */
    public FuzzyFilterPair(final byte[] row_key, final byte[] fuzzy_mask) {
      if ( row_key.length != fuzzy_mask.length ) {
        throw new IllegalArgumentException("Row key and fuzzy mask length " +
            "must match");
      }
      this.row_key = row_key;
      this.fuzzy_mask = fuzzy_mask;
    }

    /** @return the row key base filter */
    public byte[] getRowKey() {
      return row_key;
    }

    /** @return the row key mask */
    public byte[] getFuzzyMask() {
      return fuzzy_mask;
    }
  
    @Override
    public String toString() {
      final StringBuilder buf = new StringBuilder();
      buf.append("FuzzyFilterPair{row_key=")
         .append(Bytes.pretty(row_key))
         .append(", mask=")
         .append(Bytes.pretty(fuzzy_mask))
         .append("}");
      return buf.toString();
    }
  }

  /**
   * Default ctor that applies a single fuzzy filter against all row keys
   * @param filter_pair A single filter to apply to all row keys
   */
  public FuzzyRowFilter(final FuzzyFilterPair filter_pair) {
    this.filter_pairs = java.util.Collections.singleton(filter_pair);