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/*
* Copyright 2016-2019 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.core.cql;
import org.reactivestreams.Publisher;
import org.springframework.dao.DataAccessException;
import org.springframework.data.cassandra.ReactiveSession;
import com.datastax.driver.core.Statement;
import com.datastax.driver.core.exceptions.DriverException;
/**
* Generic callback interface for code that operates on a CQL {@link ReactiveSession}. Allows to execute any number of
* operations on a single {@link ReactiveSession}, using any type and number of Statements.
*
* This is particularly useful for delegating to existing data access code that expects a {@link ReactiveSession} to
* work on and throws {@link DriverException}. For newly written code, it is strongly recommended to use
* {@link CqlTemplate}'s more specific operations, for example a query or update variant.
*
* @param
* @author Mark Paluch
* @since 2.0
* @see ReactiveCqlTemplate#execute(ReactiveSessionCallback)
*/
@FunctionalInterface
public interface ReactiveSessionCallback {
/**
* Gets called by {@link ReactiveCqlTemplate#execute(ReactiveSessionCallback)} with an active Cassandra session. Does
* not need to care about activating or closing the {@link ReactiveSession}.
*
* Allows for returning a result object created within the callback, i.e. a domain object or a collection of domain
* objects. Note that there's special support for single step actions: see
* {@link ReactiveCqlTemplate#queryForObject(Statement, Class)} etc. A thrown {@link RuntimeException} is treated as
* application exception: it gets propagated to the caller of the template.
*
* @param session active Cassandra session.
* @return a result object publisher.
* @throws DriverException if thrown by a session method, to be auto-converted to a {@link DataAccessException}.
* @throws DataAccessException in case of custom exceptions.
* @see ReactiveCqlTemplate#execute(ReactivePreparedStatementCreator, ReactivePreparedStatementCallback)
*/
Publisher doInSession(ReactiveSession session) throws DriverException, DataAccessException;
}