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

Interface AsyncSessionCallback<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 AsyncSessionCallback<T>

Generic callback interface for code that operates asynchronously on a Cassandra CqlSession. 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 CqlSession to work on and throws DriverException. For newly written code, it is strongly recommended to use AsyncCqlTemplate's more specific operations, for example a query or update variant.

Since:

2.0

Author:

David Webb, Mark Paluch

See Also:

• AsyncCqlTemplate.execute(AsyncSessionCallback)
• AsyncCqlTemplate.query(java.lang.String, org.springframework.data.cassandra.core.cql.AsyncResultSetExtractor<T>)
• AsyncCqlTemplate.execute(String)

Method Summary

Modifier and Type	Method	Description
CompletableFuture<T>	doInSession(com.datastax.oss.driver.api.core.CqlSession session)	Gets called by AsyncCqlTemplate.execute(org.springframework.data.cassandra.core.cql.AsyncSessionCallback<T>) with an active Cassandra CqlSession.

Method Details

doInSession

CompletableFuture<T> doInSession(com.datastax.oss.driver.api.core.CqlSession session)
                          throws com.datastax.oss.driver.api.core.DriverException,
DataAccessException

Gets called by AsyncCqlTemplate.execute(org.springframework.data.cassandra.core.cql.AsyncSessionCallback<T>) with an active Cassandra CqlSession. Does not need to care about activating or closing the CqlSession.

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 AsyncCqlTemplate.queryForObject(java.lang.String, java.lang.Class<T>) 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.

Returns:

a result object, or CompletableFuture<Void> if none.

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)
• AsyncCqlTemplate.queryForResultSet(String)