Package org.springframework.data.cassandra.core.cql

Interface AsyncResultSetExtractor<T>

All Known Implementing Classes:
AsyncCqlTemplate.AsyncRowCallbackHandlerResultSetExtractor, AsyncRowMapperResultSetExtractor
Functional Interface:
This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.
@FunctionalInterface public interface AsyncResultSetExtractor<T>
Callback interface used by AsyncCqlTemplate's query methods. Implementations of this interface perform the actual work of extracting results from a AsyncResultSet, but don't need to worry about exception handling. DriverExceptions will be caught and handled by the calling AsyncCqlTemplate.

This interface is mainly used within the CQL framework itself. A RowMapper is usually a simpler choice for AsyncResultSet processing, mapping one result object per row instead of one result object for the entire AsyncResultSet.

Note: In contrast to a RowCallbackHandler, a AsyncResultSetExtractor object is typically stateless and thus reusable, as long as it doesn't access stateful resources or keep result state within the object.

Since:
3.0
Author:
Mark Paluch
See Also:

  • Method Summary

    Modifier and Type
    Method
    Description
    CompletableFuture<T>
    extractData(com.datastax.oss.driver.api.core.cql.AsyncResultSet resultSet)
    Implementations must implement this method to process the entire AsyncResultSet.

  • Method Details

    • extractData

      CompletableFuture<T> extractData(com.datastax.oss.driver.api.core.cql.AsyncResultSet resultSet) throws com.datastax.oss.driver.api.core.DriverException, DataAccessException
      Implementations must implement this method to process the entire AsyncResultSet.
      Parameters:
      resultSet - AsyncResultSet to extract data from.
      Returns:
      an arbitrary result object, or null if none (the extractor will typically be stateful in the latter case).
      Throws:
      com.datastax.oss.driver.api.core.DriverException - if a DriverException is encountered getting column values or navigating (that is, there's no need to catch DriverException)
      DataAccessException - in case of custom exceptions