Package org.springframework.data.cassandra.core.cql

Interface PreparedStatementCallback<T>

Functional Interface:

This is a functional interface and can therefore be used as the assignment target for a lambda expression or method reference.

@FunctionalInterface
public interface PreparedStatementCallback<T>

Generic callback interface for code that operates on a PreparedStatement. Allows to execute any number of operations on a single PreparedStatement, for example a single SyncCqlSession.execute(Statement).

Used internally by CqlTemplate, but also useful for application code. Note that the passed-in PreparedStatement can have been created by the framework or by a custom PreparedStatementCreator. However, the latter is hardly ever necessary, as most custom callback actions will perform updates in which case a standard PreparedStatement is fine. Custom actions will always set parameter values themselves, so that PreparedStatementCreator capability is not needed either.

Author:

David Webb, Mark Paluch

See Also:

• AsyncCqlTemplate.execute(String, PreparedStatementCallback)
• AsyncCqlTemplate.execute(AsyncPreparedStatementCreator, PreparedStatementCallback)
• }
• CqlTemplate.execute(PreparedStatementCreator, PreparedStatementCallback)

Method Summary

Modifier and Type	Method	Description
T	doInPreparedStatement(com.datastax.oss.driver.api.core.CqlSession session, com.datastax.oss.driver.api.core.cql.PreparedStatement preparedStatement)	Gets called by CqlTemplate.execute(String, PreparedStatementCallback) with an active CQL session and PreparedStatement.

Method Details

doInPreparedStatement

@Nullable
T doInPreparedStatement(com.datastax.oss.driver.api.core.CqlSession session,
 com.datastax.oss.driver.api.core.cql.PreparedStatement preparedStatement)
                 throws com.datastax.oss.driver.api.core.DriverException,
DataAccessException

Gets called by CqlTemplate.execute(String, PreparedStatementCallback) with an active CQL session and PreparedStatement. Does not need to care about closing the session: this will all be handled by Spring's CqlTemplate.

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 CqlTemplate.queryForObject(String, Class, Object...) etc. A thrown RuntimeException is treated as application exception, it gets propagated to the caller of the template.

Parameters:

session - active Cassandra session, must not be null.

preparedStatement - the PreparedStatement, must not be null.

Returns:

a result object.

Throws:

com.datastax.oss.driver.api.core.DriverException - if thrown by a session method, to be auto-converted to a DataAccessException.

DataAccessException - in case of custom exceptions.

See Also:

• AsyncCqlTemplate.queryForObject(String, Class, Object...)
• AsyncCqlOperations.queryForList(String, Class, Object...)
• CqlTemplate.queryForObject(String, Class, Object...)
• CqlTemplate.queryForList(String, Object...)