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/*
* Copyright 2016-2022 the original author or authors.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* https://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.springframework.data.cassandra;
import reactor.core.publisher.Flux;
import java.util.List;
import com.datastax.oss.driver.api.core.cql.ColumnDefinitions;
import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
import com.datastax.oss.driver.api.core.cql.Row;
/**
* The reactive result of a query.
*
* The retrieval of the rows of a {@link ReactiveResultSet} 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 or per-statement with
* {@link com.datastax.oss.driver.api.core.cql.SimpleStatement#setPageSize(int)}.
*
* Please note however that this {@link ReactiveResultSet} 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). If the protocol version 1 is in
* use, a {@link ReactiveResultSet} is always fetched in it's entirely and it's up to the client to make sure that no
* query can yield {@link ReactiveResultSet} that won't hold in memory.
*
* Note that this class is not thread-safe.
*
* @author Mark Paluch
* @since 2.0
* @see Flux
* @see ReactiveSession
* @see com.datastax.oss.driver.api.core.cql.AsyncResultSet
*/
public interface ReactiveResultSet {
/**
* Returns a {@link Flux} over the rows contained in this result set applying transparent paging.
*
* The {@link Flux} will stream over all records that in this {@link ReactiveResultSet} according to the reactive
* demand and fetch next result chunks by issuing the underlying query with the current {@link java.nio.ByteBuffer
* paging state} applied.
*
* @return a {@link Flux} of rows that will stream over all {@link Row rows} of the entire result.
*/
Flux rows();
/**
* Returns a {@link Flux} over the rows contained in this result set chunk. This method does not apply transparent
* paging. Use {@link java.nio.ByteBuffer paging state} from {@link #getExecutionInfo()} to issue subsequent queries
* to obtain the next result chunk.
*
* @return a {@link Flux} of rows that will stream over all {@link Row rows} in this {@link ReactiveResultSet}.
* @since 2.1
*/
Flux availableRows();
/**
* Returns the columns returned in this {@link ReactiveResultSet}.
*
* @return the columns returned in this {@link ReactiveResultSet}.
*/
ColumnDefinitions getColumnDefinitions();
/**
* If the query that produced this ResultSet was a conditional update, return whether it was successfully 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
*/
boolean wasApplied();
/**
* Returns information on the execution of the last query made for this {@link ReactiveResultSet}.
*
* Note that in most cases, a result set is fetched with only one query, but large result sets can be paged and thus
* be retrieved by multiple queries. In that case this method return the {@link ExecutionInfo} for the last query
* performed. To retrieve the information for all queries, use {@link #getAllExecutionInfo}.
*
* The returned object includes basic information such as the queried hosts, but also the Cassandra query trace if
* tracing was enabled for the query.
*
* @return the {@link ExecutionInfo} for the last query made for this {@link ReactiveResultSet}.
*/
ExecutionInfo getExecutionInfo();
/**
* Return the execution information for all queries made to retrieve this {@link ReactiveResultSet}.
*
* Unless the result set is large enough to get paged underneath, the returned list will be singleton. If paging has
* been used however, the returned list contains the {@link ExecutionInfo} objects for all the queries done to obtain
* this result set (at the time of the call) in the order those queries were made.
*
* @return a list of the {@link ExecutionInfo} for all the queries made for this {@link ReactiveResultSet}.
*/
List getAllExecutionInfo();
}