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/*
* Copyright 2013-2019 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.springframework.dao.DataAccessException;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.exceptions.DriverException;
/**
* Generic callback interface for code that operates on a Cassandra {@link Session}. Allows to execute any number of
* operations on a single session, using any type and number of statements.
*
* This is particularly useful for delegating to existing data access code that expects a {@link Session} 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 {@code query} or {@code update} variant.
*
* @author David Webb
* @author Mark Paluch
* @see CqlTemplate#execute(SessionCallback)
* @see CqlTemplate#query
* @see CqlTemplate#execute(String)
*/
@FunctionalInterface
public interface SessionCallback {
/**
* Gets called by {@link CqlTemplate#execute} with an active Cassandra {@link Session}. Does not need to care about
* activating or closing the {@link Session}.
*
* 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 CqlTemplate#queryForObject} etc. A
* thrown {@link RuntimeException} is treated as application exception: it gets propagated to the caller of the
* template.
*
* @param session active Cassandra Session, must not be {@literal null}.
* @return a result object, or {@literal null} if none.
* @throws DriverException if thrown by a Session method, to be auto-converted to a {@link DataAccessException}.
* @throws DataAccessException in case of custom exceptions.
* @see CqlTemplate#queryForObject(String, Class)
* @see CqlTemplate#queryForResultSet(String)
*/
T doInSession(Session session) throws DriverException, DataAccessException;
}