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/*
 * Copyright 2016-2020 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
 *
 *      https://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.data.cassandra.core.cql;

import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.function.Function;
import java.util.stream.StreamSupport;

import org.springframework.dao.DataAccessException;
import org.springframework.dao.support.DataAccessUtils;
import org.springframework.data.cassandra.SessionFactory;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;

import com.datastax.oss.driver.api.core.CqlSession;
import com.datastax.oss.driver.api.core.DriverException;
import com.datastax.oss.driver.api.core.cql.PreparedStatement;
import com.datastax.oss.driver.api.core.cql.ResultSet;
import com.datastax.oss.driver.api.core.cql.Row;
import com.datastax.oss.driver.api.core.cql.Statement;
import com.datastax.oss.driver.api.core.metadata.Node;

/**
 * This is the central class in the CQL core package. It simplifies the use of CQL and helps to avoid common
 * errors. It executes core CQL workflow, leaving application code to provide CQL and extract results. This class
 * executes CQL queries or updates, initiating iteration over {@link ResultSet}s and catching {@link RuntimeException}
 * exceptions and translating them to the generic, more informative exception hierarchy defined in the
 * {@code org.springframework.dao} package.
 * 

* Code using this class need only implement callback interfaces, giving them a clearly defined contract. The * {@link PreparedStatementCreator} callback interface creates a prepared statement given a Connection, providing CQL * and any necessary parameters. The {@link ResultSetExtractor} interface extracts values from a {@link ResultSet}. See * also {@link PreparedStatementBinder} and {@link RowMapper} for two popular alternative callback interfaces. *

* Can be used within a service implementation via direct instantiation with a {@link CqlSession} reference, or get * prepared in an application context and given to services as bean reference. Note: The {@link CqlSession} should * always be configured as a bean in the application context, in the first case given to the service directly, in the * second case to the prepared template. *

* Because this class is parameterizable by the callback interfaces and the * {@link org.springframework.dao.support.PersistenceExceptionTranslator} interface, there should be no need to subclass * it. *

* All CQL operations performed by this class are logged at debug level, using * "org.springframework.data.cassandra.core.cqlTemplate" as log category. *

* NOTE: An instance of this class is thread-safe once configured. * * @author David Webb * @author Matthew Adams * @author Ryan Scheidter * @author Antoine Toulme * @author John Blum * @author Mark Paluch * @author Mike Barlotta * @see PreparedStatementCreator * @see PreparedStatementBinder * @see PreparedStatementCallback * @see ResultSetExtractor * @see RowCallbackHandler * @see RowMapper * @see org.springframework.dao.support.PersistenceExceptionTranslator */ public class CqlTemplate extends CassandraAccessor implements CqlOperations { /** * Create a new, uninitialized {@link CqlTemplate}. Note: The {@link SessionFactory} has to be set before using the * instance. * * @see #setSessionFactory(SessionFactory) */ public CqlTemplate() {} /** * Create a new {@link CqlTemplate} initialized with the given {@link CqlSession}. * * @param session the active Cassandra {@link CqlSession}. * @throws IllegalStateException if {@link CqlSession} is {@literal null}. */ public CqlTemplate(CqlSession session) { Assert.notNull(session, "Session must not be null"); setSession(session); } /** * Constructs a new {@link CqlTemplate} with the given {@link SessionFactory}. * * @param sessionFactory the active Cassandra {@link SessionFactory}, must not be {@literal null}. * @see SessionFactory */ public CqlTemplate(SessionFactory sessionFactory) { Assert.notNull(sessionFactory, "SessionFactory must not be null"); setSessionFactory(sessionFactory); } // ------------------------------------------------------------------------- // Methods dealing with a plain com.datastax.oss.driver.api.core.CqlSession // ------------------------------------------------------------------------- /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(org.springframework.data.cassandra.core.cql.SessionCallback) */ @Override public T execute(SessionCallback action) throws DataAccessException { Assert.notNull(action, "Callback object must not be null"); try { return action.doInSession(getCurrentSession()); } catch (DriverException e) { throw translateException("SessionCallback", toCql(action), e); } } // ------------------------------------------------------------------------- // Methods dealing with static CQL // ------------------------------------------------------------------------- /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(java.lang.String) */ @Override public boolean execute(String cql) throws DataAccessException { Assert.hasText(cql, "CQL must not be empty"); return queryForResultSet(cql).wasApplied(); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.ResultSetExtractor) */ @Override @Nullable public T query(String cql, ResultSetExtractor resultSetExtractor) throws DataAccessException { Assert.hasText(cql, "CQL must not be empty"); Assert.notNull(resultSetExtractor, "ResultSetExtractor must not be null"); try { if (logger.isDebugEnabled()) { logger.debug("Executing CQL Statement [{}]", cql); } Statement statement = applyStatementSettings(newStatement(cql)); ResultSet results = getCurrentSession().execute(statement); return resultSetExtractor.extractData(results); } catch (DriverException e) { throw translateException("Query", cql, e); } } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.RowCallbackHandler) */ @Override public void query(String cql, RowCallbackHandler rowCallbackHandler) throws DataAccessException { query(cql, newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public List query(String cql, RowMapper rowMapper) throws DataAccessException { // noinspection ConstantConditions return query(cql, newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(java.lang.String) */ @Override public List> queryForList(String cql) throws DataAccessException { // noinspection ConstantConditions return query(cql, newResultSetExtractor(newColumnMapRowMapper())); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(java.lang.String, java.lang.Class) */ @Override public List queryForList(String cql, Class elementType) throws DataAccessException { // noinspection ConstantConditions return query(cql, newResultSetExtractor(newSingleColumnRowMapper(elementType))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForMap(java.lang.String) */ @Override public Map queryForMap(String cql) throws DataAccessException { return queryForObject(cql, newColumnMapRowMapper()); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(java.lang.String, java.lang.Class) */ @Override public T queryForObject(String cql, Class requiredType) throws DataAccessException { return queryForObject(cql, newSingleColumnRowMapper(requiredType)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(java.lang.String, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public T queryForObject(String cql, RowMapper rowMapper) throws DataAccessException { return DataAccessUtils.requiredSingleResult(query(cql, newResultSetExtractor(rowMapper))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForResultSet(java.lang.String) */ @Override public ResultSet queryForResultSet(String cql) throws DataAccessException { // noinspection ConstantConditions return query(cql, rs -> rs); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForRows(java.lang.String) */ @Override public Iterable queryForRows(String cql) throws DataAccessException { return () -> queryForResultSet(cql).iterator(); } // ------------------------------------------------------------------------- // Methods dealing with com.datastax.oss.driver.api.core.cql.Statement // ------------------------------------------------------------------------- /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(com.datastax.oss.driver.api.core.cql.Statement) */ @Override public boolean execute(Statement statement) throws DataAccessException { Assert.notNull(statement, "CQL Statement must not be null"); return queryForResultSet(statement).wasApplied(); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(com.datastax.oss.driver.api.core.cql.Statement, org.springframework.data.cassandra.core.cql.ResultSetExtractor) */ @Override public T query(Statement statement, ResultSetExtractor resultSetExtractor) throws DataAccessException { Assert.notNull(statement, "CQL Statement must not be null"); Assert.notNull(resultSetExtractor, "ResultSetExtractor must not be null"); try { if (logger.isDebugEnabled()) { logger.debug("Executing CQL Statement [{}]", statement); } return resultSetExtractor.extractData(getCurrentSession().execute(applyStatementSettings(statement))); } catch (DriverException e) { throw translateException("Query", statement.toString(), e); } } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(com.datastax.oss.driver.api.core.cql.Statement, org.springframework.data.cassandra.core.cql.RowCallbackHandler) */ @Override public void query(Statement statement, RowCallbackHandler rowCallbackHandler) throws DataAccessException { query(statement, newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(com.datastax.oss.driver.api.core.cql.Statement, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public List query(Statement statement, RowMapper rowMapper) throws DataAccessException { // noinspection ConstantConditions return query(statement, newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(com.datastax.oss.driver.api.core.cql.Statement) */ @Override public List> queryForList(Statement statement) throws DataAccessException { // noinspection ConstantConditions return query(statement, newResultSetExtractor(newColumnMapRowMapper())); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(com.datastax.oss.driver.api.core.cql.Statement, java.lang.Class) */ @Override public List queryForList(Statement statement, Class elementType) throws DataAccessException { // noinspection ConstantConditions return query(statement, newResultSetExtractor(newSingleColumnRowMapper(elementType))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForMap(com.datastax.oss.driver.api.core.cql.Statement) */ @Override public Map queryForMap(Statement statement) throws DataAccessException { // noinspection ConstantConditions return queryForObject(statement, newColumnMapRowMapper()); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(com.datastax.oss.driver.api.core.cql.Statement, java.lang.Class) */ @Override public T queryForObject(Statement statement, Class requiredType) throws DataAccessException { return queryForObject(statement, newSingleColumnRowMapper(requiredType)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(com.datastax.oss.driver.api.core.cql.Statement, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public T queryForObject(Statement statement, RowMapper rowMapper) throws DataAccessException { return DataAccessUtils.requiredSingleResult(query(statement, newResultSetExtractor(rowMapper))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForResultSet(com.datastax.oss.driver.api.core.cql.Statement) */ @Override public ResultSet queryForResultSet(Statement statement) throws DataAccessException { // noinspection ConstantConditions return query(statement, rs -> rs); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForRows(com.datastax.oss.driver.api.core.cql.Statement) */ @Override public Iterable queryForRows(Statement statement) throws DataAccessException { return () -> queryForResultSet(statement).iterator(); } // ------------------------------------------------------------------------- // Methods dealing with com.datastax.driver.core.PreparedStatement // ------------------------------------------------------------------------- /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(java.lang.String, java.lang.Object[]) */ @Override public boolean execute(String cql, Object... args) throws DataAccessException { return execute(cql, newPreparedStatementBinder(args)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(java.lang.String, org.springframework.data.cassandra.core.cql.PreparedStatementBinder) */ @Override public boolean execute(String cql, @Nullable PreparedStatementBinder psb) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), psb, ResultSet::wasApplied); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(java.lang.String, org.springframework.data.cassandra.core.cql.PreparedStatementCallback) */ @Nullable @Override public T execute(String cql, PreparedStatementCallback action) throws DataAccessException { return execute(newPreparedStatementCreator(cql), action); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(org.springframework.data.cassandra.core.cql.PreparedStatementCreator) */ @Override public boolean execute(PreparedStatementCreator preparedStatementCreator) throws DataAccessException { // noinspection ConstantConditions return query(preparedStatementCreator, ResultSet::wasApplied); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#execute(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.PreparedStatementCallback) */ @Override @Nullable public T execute(PreparedStatementCreator preparedStatementCreator, PreparedStatementCallback action) throws DataAccessException { Assert.notNull(preparedStatementCreator, "PreparedStatementCreator must not be null"); Assert.notNull(action, "PreparedStatementCallback object must not be null"); try { if (logger.isDebugEnabled()) { logger.debug("Preparing statement [{}] using {}", toCql(preparedStatementCreator), preparedStatementCreator); } CqlSession session = getCurrentSession(); return action.doInPreparedStatement(session, preparedStatementCreator.createPreparedStatement(session)); } catch (DriverException e) { throw translateException("PreparedStatementCallback", toCql(preparedStatementCreator), e); } } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.ResultSetExtractor) */ @Override public T query(PreparedStatementCreator preparedStatementCreator, ResultSetExtractor resultSetExtractor) throws DataAccessException { return query(preparedStatementCreator, null, resultSetExtractor); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.RowCallbackHandler) */ @Override public void query(PreparedStatementCreator preparedStatementCreator, RowCallbackHandler rowCallbackHandler) throws DataAccessException { query(preparedStatementCreator, null, newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public List query(PreparedStatementCreator preparedStatementCreator, RowMapper rowMapper) throws DataAccessException { // noinspection ConstantConditions return query(preparedStatementCreator, null, newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.ResultSetExtractor) */ @Nullable @Override public T query(PreparedStatementCreator preparedStatementCreator, @Nullable PreparedStatementBinder psb, ResultSetExtractor resultSetExtractor) throws DataAccessException { Assert.notNull(preparedStatementCreator, "PreparedStatementCreator must not be null"); Assert.notNull(resultSetExtractor, "ResultSetExtractor object must not be null"); try { if (logger.isDebugEnabled()) { logger.debug("Preparing statement [{}] using {}", toCql(preparedStatementCreator), preparedStatementCreator); } CqlSession session = getCurrentSession(); PreparedStatement preparedStatement = preparedStatementCreator.createPreparedStatement(session); if (logger.isDebugEnabled()) { logger.debug("Executing prepared statement [{}]", preparedStatement); } Statement boundStatement = applyStatementSettings( psb != null ? psb.bindValues(preparedStatement) : preparedStatement.bind()); ResultSet results = session.execute(boundStatement); return resultSetExtractor.extractData(results); } catch (DriverException e) { throw translateException("Query", toCql(preparedStatementCreator), e); } } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.RowCallbackHandler) */ @Override public void query(PreparedStatementCreator preparedStatementCreator, @Nullable PreparedStatementBinder psb, RowCallbackHandler rowCallbackHandler) throws DataAccessException { query(preparedStatementCreator, psb, newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(org.springframework.data.cassandra.core.cql.PreparedStatementCreator, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public List query(PreparedStatementCreator preparedStatementCreator, @Nullable PreparedStatementBinder psb, RowMapper rowMapper) throws DataAccessException { // noinspection ConstantConditions return query(preparedStatementCreator, psb, newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.ResultSetExtractor, java.lang.Object[]) */ @Override public T query(String cql, ResultSetExtractor resultSetExtractor, Object... args) throws DataAccessException { return query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), resultSetExtractor); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.RowCallbackHandler, java.lang.Object[]) */ @Override public void query(String cql, RowCallbackHandler rowCallbackHandler, Object... args) throws DataAccessException { query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.RowMapper, java.lang.Object[]) */ @Override public List query(String cql, RowMapper rowMapper, Object... args) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.ResultSetExtractor) */ @Override public T query(String cql, @Nullable PreparedStatementBinder psb, ResultSetExtractor resultSetExtractor) throws DataAccessException { return query(newPreparedStatementCreator(cql), psb, resultSetExtractor); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.RowCallbackHandler) */ @Override public void query(String cql, @Nullable PreparedStatementBinder psb, RowCallbackHandler rowCallbackHandler) throws DataAccessException { query(newPreparedStatementCreator(cql), psb, newResultSetExtractor(rowCallbackHandler)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#query(java.lang.String, org.springframework.data.cassandra.core.cql.PreparedStatementBinder, org.springframework.data.cassandra.core.cql.RowMapper) */ @Override public List query(String cql, @Nullable PreparedStatementBinder psb, RowMapper rowMapper) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), psb, newResultSetExtractor(rowMapper)); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(java.lang.String, java.lang.Object[]) */ @Override public List> queryForList(String cql, Object... args) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), newResultSetExtractor(newColumnMapRowMapper())); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForList(java.lang.String, java.lang.Class, java.lang.Object[]) */ @Override public List queryForList(String cql, Class elementType, Object... args) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), newResultSetExtractor(newSingleColumnRowMapper(elementType))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForMap(java.lang.String, java.lang.Object[]) */ @Override public Map queryForMap(String cql, Object... args) throws DataAccessException { return queryForObject(cql, newColumnMapRowMapper(), args); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(java.lang.String, java.lang.Class, java.lang.Object[]) */ @Override public T queryForObject(String cql, Class requiredType, Object... args) throws DataAccessException { return queryForObject(cql, newSingleColumnRowMapper(requiredType), args); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForObject(java.lang.String, org.springframework.data.cassandra.core.cql.RowMapper, java.lang.Object[]) */ @Override public T queryForObject(String cql, RowMapper rowMapper, Object... args) throws DataAccessException { return DataAccessUtils.requiredSingleResult( query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), newResultSetExtractor(rowMapper, 1))); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForResultSet(java.lang.String, java.lang.Object[]) */ @Override public ResultSet queryForResultSet(String cql, Object... args) throws DataAccessException { // noinspection ConstantConditions return query(newPreparedStatementCreator(cql), newPreparedStatementBinder(args), rs -> rs); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#queryForRows(java.lang.String, java.lang.Object[]) */ @Override public Iterable queryForRows(String cql, Object... args) throws DataAccessException { return () -> queryForResultSet(cql, args).iterator(); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#describeRing() */ @Override public List describeRing() throws DataAccessException { return (List) describeRing(RingMemberHostMapper.INSTANCE); } /* * (non-Javadoc) * @see org.springframework.data.cassandra.core.cqlOperations#describeRing(org.springframework.data.cassandra.core.cql.HostMapper) */ @Override public Collection describeRing(HostMapper hostMapper) throws DataAccessException { Assert.notNull(hostMapper, "HostMapper must not be null"); return hostMapper.mapHosts(getHosts()); } /* (non-Javadoc) */ private Collection getHosts() { return getCurrentSession().getMetadata().getNodes().values(); } // ------------------------------------------------------------------------- // Implementation hooks and helper methods // ------------------------------------------------------------------------- /** * Translate the given {@link RuntimeException} into a generic {@link DataAccessException}. * * @param task readable text describing the task being attempted * @param cql CQL query or update that caused the problem (may be {@literal null}) * @param RuntimeException the offending {@code RuntimeException}. * @return the exception translation {@link Function} * @see CqlProvider */ protected DataAccessException translateException(String task, @Nullable String cql, RuntimeException RuntimeException) { return translate(task, cql, RuntimeException); } /** * Create a new CQL-based {@link PreparedStatementCreator} using the CQL passed in. By default, we'll create an * {@link SimplePreparedStatementCreator}. This method allows for the creation to be overridden by subclasses. * * @param cql static CQL to execute, must not be empty or {@literal null}. * @return the new {@link PreparedStatementCreator} to use */ protected PreparedStatementCreator newPreparedStatementCreator(String cql) { return new SimplePreparedStatementCreator(cql); } /** * Constructs a new instance of the {@link ResultSetExtractor} initialized with and adapting the given * {@link RowCallbackHandler}. * * @param rowCallbackHandler {@link RowCallbackHandler} to adapt as a {@link ResultSetExtractor}. * @return a {@link ResultSetExtractor} implementation adapting an instance of the {@link RowCallbackHandler}. * @see AsyncCqlTemplate.AsyncRowCallbackHandlerResultSetExtractor * @see ResultSetExtractor * @see RowCallbackHandler */ protected RowCallbackHandlerResultSetExtractor newResultSetExtractor(RowCallbackHandler rowCallbackHandler) { return new RowCallbackHandlerResultSetExtractor(rowCallbackHandler); } /** * Constructs a new instance of the {@link ResultSetExtractor} initialized with and adapting the given * {@link RowMapper}. * * @param rowMapper {@link RowMapper} to adapt as a {@link ResultSetExtractor}. * @return a {@link ResultSetExtractor} implementation adapting an instance of the {@link RowMapper}. * @see ResultSetExtractor * @see RowMapper * @see RowMapperResultSetExtractor */ protected RowMapperResultSetExtractor newResultSetExtractor(RowMapper rowMapper) { return new RowMapperResultSetExtractor<>(rowMapper); } /** * Constructs a new instance of the {@link ResultSetExtractor} initialized with and adapting the given * {@link RowMapper}. * * @param rowMapper {@link RowMapper} to adapt as a {@link ResultSetExtractor}. * @param rowsExpected number of expected rows in the {@link ResultSet}. * @return a {@link ResultSetExtractor} implementation adapting an instance of the {@link RowMapper}. * @see ResultSetExtractor * @see RowMapper * @see RowMapperResultSetExtractor */ protected RowMapperResultSetExtractor newResultSetExtractor(RowMapper rowMapper, int rowsExpected) { return new RowMapperResultSetExtractor<>(rowMapper, rowsExpected); } private CqlSession getCurrentSession() { SessionFactory sessionFactory = getSessionFactory(); Assert.state(sessionFactory != null, "SessionFactory is null"); return sessionFactory.getSession(); } /** * Adapter to enable use of a {@link RowCallbackHandler} inside a {@link ResultSetExtractor}. */ protected static class RowCallbackHandlerResultSetExtractor implements ResultSetExtractor { private final RowCallbackHandler rowCallbackHandler; protected RowCallbackHandlerResultSetExtractor(RowCallbackHandler rowCallbackHandler) { this.rowCallbackHandler = rowCallbackHandler; } /* (non-Javadoc) * @see org.springframework.data.cassandra.core.cql.ResultSetExtractor#extractData(com.datastax.driver.core.ResultSet) */ @Override @Nullable public Object extractData(ResultSet resultSet) { StreamSupport.stream(resultSet.spliterator(), false).forEach(rowCallbackHandler::processRow); return null; } } }