com.datastax.dse.driver.api.core.cql.reactive.ReactiveQueryMetadata Maven / Gradle / Ivy
/*
* Copyright DataStax, Inc.
*
* 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
*
* http://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 com.datastax.dse.driver.api.core.cql.reactive;
import com.datastax.oss.driver.api.core.cql.ColumnDefinitions;
import com.datastax.oss.driver.api.core.cql.ExecutionInfo;
import edu.umd.cs.findbugs.annotations.NonNull;
import org.reactivestreams.Publisher;
/**
* Interface implemented by all the reactive result set publishers provided by the driver, and
* notably by {@link ReactiveResultSet}.
*/
public interface ReactiveQueryMetadata {
/**
* Returns metadata about the {@linkplain ColumnDefinitions columns} contained in this result set.
*
* This publisher emits exactly one item as soon as the first response arrives, then completes.
* If the query execution fails within the first request-response cycle, then this
* publisher will fail with the same error; however if the error happens after the first
* response, then this publisher will be already completed and will not acknowledge that
* error in any way.
*
*
By default, publishers returned by this method do not support multiple subscriptions.
*
* @see ReactiveRow#getColumnDefinitions()
*/
@NonNull
Publisher getColumnDefinitions();
/**
* Returns {@linkplain ExecutionInfo information about the execution} of all requests that have
* been performed so far to assemble this result set.
*
*
If the query is not paged, this publisher will emit exactly one item as soon as the response
* arrives, then complete. If the query is paged, it will emit multiple items, one per page; then
* it will complete when the last page arrives. If the query execution fails, then this publisher
* will fail with the same error.
*
*
By default, publishers returned by this method do not support multiple subscriptions.
*
* @see ReactiveRow#getExecutionInfo()
*/
@NonNull
Publisher getExecutionInfos();
/**
* If the query that produced this result was a conditional update, indicates whether it was
* successfully applied.
*
*
This publisher emits exactly one item as soon as the first response arrives, then completes.
* If the query execution fails within the first request-response cycle, then this
* publisher will fail with the same error; however if the error happens after the first
* response, then this publisher will be already completed and will not acknowledge that
* error in any way.
*
*
By default, publishers returned by this method do not support multiple subscriptions.
*
*
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 2.1.0-rc2, a server-side bug (CASSANDRA-7337) causes this
* method to always return {@code true} for batches containing conditional queries.
*
* @see ReactiveRow#wasApplied()
*/
@NonNull
Publisher wasApplied();
}