SingleColumnValueFilterAdapter (Cloud Bigtable HBase Client for Java 1.12.0 API)

Constructor Detail

• SingleColumnValueFilterAdapter

  public SingleColumnValueFilterAdapter(ValueFilterAdapter delegateAdapter)

  Constructor for SingleColumnValueFilterAdapter.

  Parameters:

  delegateAdapter - a ValueFilterAdapter object.

Method Detail

• adapt

  public com.google.cloud.bigtable.data.v2.models.Filters.Filter adapt(FilterAdapterContext context,
                                                                       SingleColumnValueFilter filter)
                                                                throws IOException

  SingleColumnValueFilter is a filter that will return a row if a family/qualifier value matches some condition. Optionally, if SingleColumnValueFilter.getFilterIfMissing() is set to false, then also return the row if the family/column is not present on the row. There's a

  Here's a rough translation of SingleColumnValueFilter.getFilterIfMissing() == true.

   IF a single family/column exists AND
      the value of the family/column meets some condition THEN
         return the ROW
   END
   

  Here's a rough translation of SingleColumnValueFilter.getFilterIfMissing() == false.

   IF a single family/column exists THEN
     IF the value of the family/column meets some condition THEN
       return the ROW
     END
   ELSE IF filter.filter_if_missing == false THEN
     return the ROW
   END
   

  The Cloud Bigtable filter translation for the SingleColumnValueFilter.getFilterIfMissing() true case here's the resulting filter is as follows:

     condition: {
        predicate: {
          chain: {
             family: [filter.family]
             qualifier: [filter.qualifier],
             // if filter.latestOnly, then add
             // cells_per_column: 1
             value: // something interesting
          }
        }
        true_filter: {
           pass_all: true
        }
     }
   

  In addition to the default filter, there's a bit more if SingleColumnValueFilter.getFilterIfMissing() is false. Here's what the filter would look like:

     interleave: [ // either
       {
         // If the family/qualifier exists and matches a value
         // Then return the row
         // Else return nothing
         condition: {
           predicate: {
             chain: {
               family: [filter.family]
               qualifier: [filter.qualifier],
               // if filter.latestOnly, then add
               // cells_per_column: 1
               value: // something interesting
             }
           },
           true_filter: { pass_all: true }
         }
       }, {
         // If the family/qualifer exists
         // Then return nothing
         // Else return row
         condition: {
           predicate: {
             chain: {
               family: [filter.family]
               qualifier: [filter.qualifier],
             }
           },
           false_filter: { pass_all: true }
         }
       }
     ]
   

  NOTE: This logic can also be expressed as nested predicates, but that approach creates really poor performance on the server side.

  Parameters:

  context - a FilterAdapterContext object.

  filter - a S object.

  Returns:

  a Filters.Filter object.

  Throws:

  IOException - if any.

• isFilterSupported

  public FilterSupportStatus isFilterSupported(FilterAdapterContext context,
                                               SingleColumnValueFilter filter)

  Determine if the given filter can be adapted to a Bigtable RowFilter.

  Parameters:

  context - a FilterAdapterContext object.

  filter - a S object.

  Returns:

  a FilterSupportStatus object.