org.springframework.data.cassandra.core.cql

Class CassandraAccessor

java.lang.Object

org.springframework.data.cassandra.core.cql.CassandraAccessor

All Implemented Interfaces:

InitializingBean

Direct Known Subclasses:

AsyncCqlTemplate, CqlTemplate

public class CassandraAccessor
extends Object
implements InitializingBean

CassandraAccessor provides access to a Cassandra SessionFactory and the CassandraExceptionTranslator.

Classes providing a higher abstraction level usually extend CassandraAccessor to provide a richer set of functionality on top of a SessionFactory using Session.

Author:

David Webb, Mark Paluch, John Blum

See Also:

InitializingBean, Session

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
protected static class	CassandraAccessor.RowCallbackHandlerResultSetExtractor Adapter to enable use of a RowCallbackHandler inside a ResultSetExtractor.

Field Summary

Fields

Modifier and Type	Field and Description
protected org.slf4j.Logger	logger Logger available to subclasses

Constructor Summary

Constructors

Constructor and Description
CassandraAccessor()

Method Summary

Modifier and Type	Method and Description
void	afterPropertiesSet() Ensures the Cassandra Session and exception translator has been propertly set.
protected <T extends com.datastax.driver.core.PreparedStatement> T	applyStatementSettings(T statement) Prepare the given CQL Statement (or PreparedStatement), applying statement settings such as retry policy and consistency level.
protected <T extends com.datastax.driver.core.Statement> T	applyStatementSettings(T statement) Prepare the given CQL Statement (or PreparedStatement), applying statement settings such as fetch size, retry policy, and consistency level.
com.datastax.driver.core.ConsistencyLevel	getConsistencyLevel()
CqlExceptionTranslator	getExceptionTranslator() Return the exception translator used by this template to translate Cassandra specific Exceptions into Spring DAO's Exception Hierarchy.
int	getFetchSize()
com.datastax.driver.core.policies.RetryPolicy	getRetryPolicy()
com.datastax.driver.core.Session	getSession() Deprecated. since 2.0. This class uses a SessionFactory to dispatch CQL calls amongst different Sessions during its lifecycle.
SessionFactory	getSessionFactory() Returns the Cassandra SessionFactory used by this template to perform Cassandra data access operations.
protected RowMapper<Map<String,Object>>	newColumnMapRowMapper() Create a new RowMapper for reading columns as key-value pairs.
protected PreparedStatementBinder	newPreparedStatementBinder(Object[] args) Create a new arg-based PreparedStatementSetter using the args passed in.
protected CassandraAccessor.RowCallbackHandlerResultSetExtractor	newResultSetExtractor(RowCallbackHandler rowCallbackHandler) Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowCallbackHandler.
protected <T> RowMapperResultSetExtractor<T>	newResultSetExtractor(RowMapper<T> rowMapper) Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowMapper.
protected <T> RowMapperResultSetExtractor<T>	newResultSetExtractor(RowMapper<T> rowMapper, int rowsExpected) Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowMapper.
protected <T> RowMapper<T>	newSingleColumnRowMapper(Class<T> requiredType) Create a new RowMapper for reading result objects from a single column.
void	setConsistencyLevel(com.datastax.driver.core.ConsistencyLevel consistencyLevel) Set the consistency level for this template.
void	setExceptionTranslator(CqlExceptionTranslator exceptionTranslator) Sets the exception translator used by this template to translate Cassandra specific Exceptions into Spring DAO's Exception Hierarchy.
void	setFetchSize(int fetchSize) Set the fetch size for this template.
void	setRetryPolicy(com.datastax.driver.core.policies.RetryPolicy retryPolicy) Set the retry policy for this template.
void	setSession(com.datastax.driver.core.Session session) Sets the Cassandra Session used by this template to perform Cassandra data access operations.
void	setSessionFactory(SessionFactory sessionFactory) Sets the Cassandra SessionFactory used by this template to perform Cassandra data access operations.
protected static String	toCql(Object cqlProvider) Determine CQL from potential provider object.
protected DataAccessException	translate(String task, String cql, com.datastax.driver.core.exceptions.DriverException ex) Translate the given DriverException into a generic DataAccessException.
protected DataAccessException	translateExceptionIfPossible(com.datastax.driver.core.exceptions.DriverException ex) Translate the given DriverException into a generic DataAccessException.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected final org.slf4j.Logger logger

Logger available to subclasses

Constructor Detail

CassandraAccessor

public CassandraAccessor()

Method Detail

afterPropertiesSet

public void afterPropertiesSet()

Ensures the Cassandra Session and exception translator has been propertly set.

Specified by:

afterPropertiesSet in interface InitializingBean

setConsistencyLevel

public void setConsistencyLevel(@Nullable
                                com.datastax.driver.core.ConsistencyLevel consistencyLevel)

Set the consistency level for this template. Consistency level defines the number of nodes involved into query processing. Relaxed consistency level settings use fewer nodes but eventual consistency is more likely to occur while a higher consistency level involves more nodes to obtain results with a higher consistency guarantee.

See Also:

Statement.setConsistencyLevel(ConsistencyLevel), RetryPolicy

getConsistencyLevel

@Nullable
public com.datastax.driver.core.ConsistencyLevel getConsistencyLevel()

Returns:

the ConsistencyLevel specified for this template.

setExceptionTranslator

public void setExceptionTranslator(CqlExceptionTranslator exceptionTranslator)

Sets the exception translator used by this template to translate Cassandra specific Exceptions into Spring DAO's Exception Hierarchy.

Parameters:

exceptionTranslator - exception translator to set; must not be null.

See Also:

CqlExceptionTranslator

getExceptionTranslator

public CqlExceptionTranslator getExceptionTranslator()

Return the exception translator used by this template to translate Cassandra specific Exceptions into Spring DAO's Exception Hierarchy.

Returns:

the Cassandra exception translator.

See Also:

CqlExceptionTranslator

setFetchSize

public void setFetchSize(int fetchSize)

Set the fetch size for this template. This is important for processing large result sets: Setting this higher than the default value will increase processing speed at the cost of memory consumption; setting this lower can avoid transferring row data that will never be read by the application. Default is -1, indicating to use the CQL driver's default configuration (i.e. to not pass a specific fetch size setting on to the driver).

See Also:

Statement.setFetchSize(int)

getFetchSize

public int getFetchSize()

Returns:

the fetch size specified for this template.

setRetryPolicy

public void setRetryPolicy(@Nullable
                           com.datastax.driver.core.policies.RetryPolicy retryPolicy)

Set the retry policy for this template. This is important for defining behavior when a request fails.

See Also:

Statement.setRetryPolicy(RetryPolicy), RetryPolicy

getRetryPolicy

@Nullable
public com.datastax.driver.core.policies.RetryPolicy getRetryPolicy()

Returns:

the RetryPolicy specified for this template.

setSession

public void setSession(com.datastax.driver.core.Session session)

Sets the Cassandra Session used by this template to perform Cassandra data access operations. The session will replace the current getSessionFactory() with DefaultSessionFactory.

Parameters:

session - Cassandra Session used by this template, must not benull.

See Also:

Session, DefaultSessionFactory

getSession

@Deprecated
public com.datastax.driver.core.Session getSession()

Deprecated. since 2.0. This class uses a SessionFactory to dispatch CQL calls amongst different Sessions during its lifecycle.

Returns the Cassandra Session from SessionFactory used by this template to perform Cassandra data access operations.

Returns:

the Cassandra Session used by this template.

See Also:

Session

setSessionFactory

public void setSessionFactory(SessionFactory sessionFactory)

Sets the Cassandra SessionFactory used by this template to perform Cassandra data access operations.

Parameters:

sessionFactory - Cassandra Session used by this template. Must not benull.

Since:

2.0

See Also:

Session

getSessionFactory

@Nullable
public SessionFactory getSessionFactory()

Returns the Cassandra SessionFactory used by this template to perform Cassandra data access operations.

Returns:

the Cassandra SessionFactory used by this template.

Since:

2.0

See Also:

SessionFactory

applyStatementSettings

protected <T extends com.datastax.driver.core.PreparedStatement> T applyStatementSettings(T statement)

Prepare the given CQL Statement (or PreparedStatement), applying statement settings such as retry policy and consistency level.

Parameters:

statement - the CQL Statement to prepare

See Also:

setRetryPolicy(RetryPolicy), setConsistencyLevel(ConsistencyLevel)

applyStatementSettings

protected <T extends com.datastax.driver.core.Statement> T applyStatementSettings(T statement)

Prepare the given CQL Statement (or PreparedStatement), applying statement settings such as fetch size, retry policy, and consistency level.

Parameters:

statement - the CQL Statement to prepare

See Also:

setFetchSize(int), setRetryPolicy(RetryPolicy), setConsistencyLevel(ConsistencyLevel)

translateExceptionIfPossible

@Nullable
protected DataAccessException translateExceptionIfPossible(com.datastax.driver.core.exceptions.DriverException ex)

Translate the given DriverException into a generic DataAccessException.

The returned DataAccessException is supposed to contain the original DriverException as root cause. However, client code may not generally rely on this due to DataAccessExceptions possibly being caused by other resource APIs as well. That said, a getRootCause() instanceof DataAccessException check (and subsequent cast) is considered reliable when expecting Cassandra-based access to have happened.

Parameters:

ex - the offending DriverException

Returns:

the DataAccessException, wrapping the DriverException

See Also:

Consistent exception hierarchy, DataAccessException

translate

protected DataAccessException translate(String task,
                                        @Nullable
                                        String cql,
                                        com.datastax.driver.core.exceptions.DriverException ex)

Translate the given DriverException into a generic DataAccessException.

The returned DataAccessException is supposed to contain the original DriverException as root cause. However, client code may not generally rely on this due to DataAccessExceptions possibly being caused by other resource APIs as well. That said, a getRootCause() instanceof DataAccessException check (and subsequent cast) is considered reliable when expecting Cassandra-based access to have happened.

Parameters:

task - readable text describing the task being attempted

cql - CQL query or update that caused the problem (may be null)

ex - the offending DriverException

Returns:

the DataAccessException, wrapping the DriverException

See Also:

NestedRuntimeException.getRootCause(), Consistent exception hierarchy

newPreparedStatementBinder

protected PreparedStatementBinder newPreparedStatementBinder(Object[] args)

Create a new arg-based PreparedStatementSetter using the args passed in. By default, we'll create an ArgumentPreparedStatementBinder. This method allows for the creation to be overridden by subclasses.

Parameters:

args - object array with arguments

Returns:

the new PreparedStatementBinder to use

newResultSetExtractor

protected CassandraAccessor.RowCallbackHandlerResultSetExtractor newResultSetExtractor(RowCallbackHandler rowCallbackHandler)

Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowCallbackHandler.

Parameters:

rowCallbackHandler - RowCallbackHandler to adapt as a ResultSetExtractor.

Returns:

a ResultSetExtractor implementation adapting an instance of the RowCallbackHandler.

See Also:

AsyncCqlTemplate.RowCallbackHandlerResultSetExtractor, ResultSetExtractor, RowCallbackHandler

newResultSetExtractor

protected <T> RowMapperResultSetExtractor<T> newResultSetExtractor(RowMapper<T> rowMapper)

Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowMapper.

Parameters:

rowMapper - RowMapper to adapt as a ResultSetExtractor.

Returns:

a ResultSetExtractor implementation adapting an instance of the RowMapper.

See Also:

ResultSetExtractor, RowMapper, RowMapperResultSetExtractor

newResultSetExtractor

protected <T> RowMapperResultSetExtractor<T> newResultSetExtractor(RowMapper<T> rowMapper,
                                                                   int rowsExpected)

Constructs a new instance of the ResultSetExtractor initialized with and adapting the given RowMapper.

Parameters:

rowMapper - RowMapper to adapt as a ResultSetExtractor.

rowsExpected - number of expected rows in the ResultSet.

Returns:

a ResultSetExtractor implementation adapting an instance of the RowMapper.

See Also:

ResultSetExtractor, RowMapper, RowMapperResultSetExtractor

newColumnMapRowMapper

protected RowMapper<Map<String,Object>> newColumnMapRowMapper()

Create a new RowMapper for reading columns as key-value pairs.

Returns:

the RowMapper to use

See Also:

ColumnMapRowMapper

newSingleColumnRowMapper

protected <T> RowMapper<T> newSingleColumnRowMapper(Class<T> requiredType)

Create a new RowMapper for reading result objects from a single column.

Parameters:

requiredType - the type that each result object is expected to match

Returns:

the RowMapper to use

See Also:

SingleColumnRowMapper

toCql

@Nullable
protected static String toCql(@Nullable
                                        Object cqlProvider)

Determine CQL from potential provider object.

Parameters:

cqlProvider - object that's potentially a CqlProvider

Returns:

the CQL string, or null

See Also:

CqlProvider