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

Interface ReactivePreparedStatementCallback<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 ReactivePreparedStatementCallback<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 ReactiveSession.execute(Statement).

Used internally by ReactiveCqlTemplate, but also useful for application code. Note that the passed-in PreparedStatement can have been created by the framework or by a custom ReactivePreparedStatementCreator. 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 ReactivePreparedStatementCreator capability is not needed either.

Since:

2.0

Author:

Mark Paluch

See Also:

• ReactiveCqlTemplate.execute(ReactivePreparedStatementCreator, ReactivePreparedStatementCallback)
• ReactiveCqlTemplate.execute(String, ReactivePreparedStatementCallback)

Method Summary

Modifier and Type	Method	Description
org.reactivestreams.Publisher<T>	doInPreparedStatement(ReactiveSession session, com.datastax.oss.driver.api.core.cql.PreparedStatement ps)	Gets called by ReactiveCqlTemplate.execute(String, ReactivePreparedStatementCallback) with an active CQL session and PreparedStatement.

Method Details

doInPreparedStatement

org.reactivestreams.Publisher<T> doInPreparedStatement(ReactiveSession session,
 com.datastax.oss.driver.api.core.cql.PreparedStatement ps)
                                                throws com.datastax.oss.driver.api.core.DriverException,
DataAccessException

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

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 ReactiveCqlTemplate.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.

ps - the PreparedStatement, must not be null.

Returns:

a result object publisher.

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:

• ReactiveCqlTemplate.queryForObject(String, Class, Object...)
• ReactiveCqlTemplate.queryForFlux(String, Object...)