PreparedStatementCallback.java

/*
 * Copyright 2013-2017 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
 *
 * 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 org.springframework.cassandra.core;

import org.springframework.dao.DataAccessException;

import com.datastax.driver.core.PreparedStatement;
import com.datastax.driver.core.Session;
import com.datastax.driver.core.Statement;
import com.datastax.driver.core.exceptions.DriverException;

/**
 * Generic callback interface for code that operates on a {@link PreparedStatement}. Allows to execute any number of
 * operations on a single {@link PreparedStatement}, for example a single {@link Session#execute(Statement).
 * <p>
 * Used internally by {@link CqlTemplate}, but also useful for application code. Note that the passed-in
 * {@link PreparedStatement} can have been created by the framework or by a custom {@link PreparedStatementCreator}.
 * However, the latter is hardly ever necessary, as most custom callback actions will perform updates in which case a
 * standard {@link PreparedStatement is fine. Custom actions will always set parameter values themselves, so that
 * {@link PreparedStatementCreator} capability is not needed either.
 *
 * @author David Webb
 * @author Mark Paluch
 * @see AsyncCqlTemplate#execute(String, PreparedStatementCallback)
 * @see AsyncCqlTemplate#execute(PreparedStatementCreator, PreparedStatementCallback)
 * @see CqlTemplate#execute(String, PreparedStatementCallback)
 * @see CqlTemplate#execute(PreparedStatementCreator, PreparedStatementCallback)
 */
public interface PreparedStatementCallback<T> {

	/**
	 * Gets called by {@link CqlTemplate#execute(String, PreparedStatementCallback)} with an active CQL session and
	 * {@link PreparedStatement}. Does not need to care about closing the session: this will all be handled by Spring's
	 * {@link CqlTemplate}.
	 * <p>
	 * 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(String, Class, Object...)} etc. A thrown 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}.
	 * @param preparedStatement the {@link PreparedStatement}, must not be {@literal null}.
	 * @return a result object publisher.
	 * @throws DriverException if thrown by a session method, to be auto-converted to a DataAccessException.
	 * @throws DataAccessException in case of custom exceptions.
	 * @see AsyncCqlTemplate#queryForObject(String, Class, Object...)
	 * @see AsyncCqlTemplate#queryForList(String, Class, Object...)
	 * @see CqlTemplate#queryForObject(String, Class, Object...)
	 * @see CqlTemplate#queryForList(String, Object...)
	 */
	T doInPreparedStatement(Session session, PreparedStatement preparedStatement)
			throws DriverException, DataAccessException;
}