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A driver for DataStax Enterprise (DSE) and Apache Cassandra 1.2+ clusters that works exclusively with the Cassandra Query Language version 3 (CQL3) and Cassandra's binary protocol, supporting DSE-specific features such as geospatial types, DSE Graph and DSE authentication.

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/*
 * Copyright (C) 2012-2017 DataStax Inc.
 *
 * This software can be used solely with DataStax Enterprise. Please consult the license at
 * http://www.datastax.com/terms/datastax-dse-driver-license-terms
 */
package com.datastax.driver.core;


/**
 * The result of a query.
 * 
 * The retrieval of the rows of a ResultSet is generally paged (a first page
 * of result is fetched and the next one is only fetched once all the results
 * of the first one has been consumed). The size of the pages can be configured
 * either globally through {@link QueryOptions#setFetchSize} or per-statement
 * with {@link Statement#setFetchSize}. Though new pages are automatically (and
 * transparently) fetched when needed, it is possible to force the retrieval
 * of the next page early through {@link #fetchMoreResults}. Please note however
 * that this ResultSet paging is not available with the version 1 of the native
 * protocol (i.e. with Cassandra 1.2 or if version 1 has been explicitly requested
 * through {@link Cluster.Builder#withProtocolVersion}). If the protocol version 1
 * is in use, a ResultSet is always fetched in it's entirely and it's up to the
 * client to make sure that no query can yield ResultSet that won't hold in memory.
 * 

 * Note that this class is not thread-safe.
 */
public interface ResultSet extends PagingIterable {

    // redeclared only to make clirr happy
    @Override
    Row one();

    /**
     * Returns the columns returned in this ResultSet.
     *
     * @return the columns returned in this ResultSet.
     */
    public ColumnDefinitions getColumnDefinitions();

    /**
     * If the query that produced this ResultSet was a conditional update,
     * return whether it was successfully applied.
     * 

     * This is equivalent to calling:
     * 

     * 
     * rs.one().getBool("[applied]");
     * 
     * 
     * For consistency, this method always returns {@code true} for
     * non-conditional queries (although there is no reason to call the method
     * in that case). This is also the case for conditional DDL statements
     * ({@code CREATE KEYSPACE... IF NOT EXISTS}, {@code CREATE TABLE... IF NOT EXISTS}),
     * for which Cassandra doesn't return an {@code [applied]} column.
     * 
     * Note that, for versions of Cassandra strictly lower than 2.0.9 and 2.1.0-rc2,
     * a server-side bug (CASSANDRA-7337) causes this method to always return
     * {@code true} for batches containing conditional queries.
     *
     * @return if the query was a conditional update, whether it was applied.
     * {@code true} for other types of queries.
     * @see CASSANDRA-7337
     */
    public boolean wasApplied();
}