I have moved all the Cassandra into single class. When I tried create instance of CassandraOperations in the gemfire cache listener was getting null pointer exception.Can you please assist me on this error
I have not received any null pointer exception using spring and cassandra but getting while integrating with gemfire.
#Component
public class CacheListener<K, V> extends CacheListenerAdapter<K, V> implements Declarable {
#Autowired
private CassandraOperations cassandraOperations;
#Override
public void init(Properties props) {
}
public void afterCreate(EntryEvent e) {
cassandraOperations.insert(e.getNewValue());
}
#Override
public void close() {
}
}
public class CassandraConfig {
#Autowired
private Environment environment;
private static final Logger LOGGER = LoggerFactory.getLogger(CassandraConfig.class);
#Bean
public CassandraClusterFactoryBean cluster() {
CassandraClusterFactoryBean cluster = new CassandraClusterFactoryBean();
cluster.setContactPoints(environment.getProperty("cassandra.contactpoints"));
cluster.setPort(Integer.parseInt(environment.getProperty("cassandra.port")));
return cluster;
}
#Bean
public CassandraMappingContext mappingContext() {
BasicCassandraMappingContext mappingContext = new BasicCassandraMappingContext();
mappingContext.setUserTypeResolver(new SimpleUserTypeResolver(cluster().getObject(), environment.getProperty("cassandra.keyspace"))); return mappingContext;
}
#Bean
public CassandraConverter converter() {
return new MappingCassandraConverter(mappingContext());
}
#Bean
public CassandraSessionFactoryBean session() throws Exception {
CassandraSessionFactoryBean session = new CassandraSessionFactoryBean();
session.setCluster(cluster().getObject());
session.setKeyspaceName(environment.getProperty("cassandra.keyspace"));
session.setConverter(converter());
session.setSchemaAction(SchemaAction.NONE);
return session;
}
#Bean
public CassandraOperations cassandraTemplate() throws Exception {
return new CassandraTemplate(session().getObject());
}
}
Exception
[error 2017/05/05 11:16:04.874 CDT <http-nio-7878-exec-1> tid=0x5b] Exception occurred in CacheListener
java.lang.NullPointerException
at CacheListener.afterCreate(CacheListener.java:27)
at com.gemstone.gemfire.internal.cache.EnumListenerEvent$AFTER_CREATE.dispatchEvent(EnumListenerEvent.java:97)
at com.gemstone.gemfire.internal.cache.LocalRegion.dispatchEvent(LocalRegion.java:8897)
at com.gemstone.gemfire.internal.cache.LocalRegion.dispatchListenerEvent(LocalRegion.java:7376)
at com.gemstone.gemfire.internal.cache.LocalRegion.invokePutCallbacks(LocalRegion.java:6158)
at com.gemstone.gemfire.internal.cache.EntryEventImpl.invokeCallbacks(EntryEventImpl.java:1919)
at com.gemstone.gemfire.internal.cache.ProxyRegionMap$ProxyRegionEntry.dispatchListenerEvents(ProxyRegionMap.java:548)
at com.gemstone.gemfire.internal.cache.LocalRegion.basicPutPart2(LocalRegion.java:6012)
at com.gemstone.gemfire.internal.cache.ProxyRegionMap.basicPut(ProxyRegionMap.java:232)
at com.gemstone.gemfire.internal.cache.LocalRegion.virtualPut(LocalRegion.java:5824)
at com.gemstone.gemfire.internal.cache.LocalRegionDataView.putEntry(LocalRegionDataView.java:118)
at com.gemstone.gemfire.internal.cache.LocalRegion.basicPut(LocalRegion.java:5214)
at com.gemstone.gemfire.internal.cache.LocalRegion.validatedPut(LocalRegion.java:1597)
at com.gemstone.gemfire.internal.cache.LocalRegion.put(LocalRegion.java:1580)
at com.gemstone.gemfire.internal.cache.AbstractRegion.put(AbstractRegion.java:327)
at org.springframework.data.gemfire.GemfireTemplate.put(GemfireTemplate.java:189)
at org.springframework.data.gemfire.repository.support.SimpleGemfireRepository.save(SimpleGemfireRepository.java:84)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:498)
What is not apparent in your code/configuration above is how you configured your application-specific, GemFire CacheListener using Spring (Data GemFire).
I see you annotated your application CacheListener using Spring's #Component stereo-type annotation, but this does nothing without help.
Are you using Spring's Classpath component scanning functionality, or perhaps Spring's Annotation-based container configuration support? If you are using the later, you know you have to still explicitly define your application CacheListener in config (JavaConfig or XML), right?
Whenever you encounter a NullPointerException on an #Autowired component/collaborator field to inject a dependency, especially when using Spring's #Autowired annotation, it is good indication you have a configuration problem, particularly since the #Autowired annotation implies that the "dependency" (e.g. CassandraOperations) is "required" (unless you explicitly set the required attribute of the #Autowired annotation to false, which you did not; required defaults to true).
Therefore, if the CacheListener component were picked up in the scan and a dependency could not be injected (auto-wired) because no (other) bean of the specified type (e.g. CassandraOperations) was defined in the Spring application context (which it is), then Spring would throw an Exception when evaluating your configuration class(es).
Although, even your CassandraConfig class must also be annotated with Spring's #Configuration annotation or with the #Component annotation when using either Spring Classpath component scanning or Annotation-based container config. Or, it must be explicitly defined as a bean in the Spring application context if using neither.
NOTE: the naming convention (i.e. CacheListener) is not very good since it clashes with GemFire's own CacheListener interface. It would be better to call your application-specific extension/implementation perhaps, "GemFireToCassandraCacheListener"
By way of example...
import ...;
#Configuration
class GemFireConfiguration {
#Bean
CacheFactoryBean gemfireCache() {
return new CacheFactoryBean();
}
#Bean("CassandraCache")
PartitionedRegionFactoryBean cassandraCacheRegion() {
PartitionedRegionFactoryBean cassandraCacheRegion =
new PartitionedRegionFactoryBean();
cassandraCacheRegion.setCache(gemfireCache());
cassandraCacheRegion.setClose(false);
cassandraCacheRegion.setCacheListeners(
new CacheListener[] { gemfireToCassandraCacheListener() });
return cassandraCacheRegion;
}
#Bean
GemFireToCassandraCacheListener gemfireToCassandraCacheListener() {
return new GemFireToCassandraCacheListener();
}
}
import ...;
#Configuration
class CassandraConfig {
// what you have above
}
I have plenty of GemFire configuration examples here, that shows GemFire native config with Spring (Data GemFire) config, XML vs. JavaConfig vs. annotations, etc, etc.
Finally...
Technically, it might be better to use a GemFire CacheWriter, attached to the Region, rather than a CacheListener, since what you are doing (updating Cassandra on a cache create) is the intended purpose of a CacheWriter.
Of course, the CacheListener is called "after" create vs. the CacheWriter which is "before" create. However, I would say it is always better to update the "primary" data source (or "source of truth") before updating the "cache" to reflect the data source. This is applicable especially if there are constraints in the primary data source that might cause an update to fail. You would not want the cache to be updated if the primary data source could not be.
A CacheWriter is configured similarly to a CacheListener, like so...
#Bean("CassandraCache")
PartitionedRegionFactoryBean cassandraCacheRegion() {
PartitionedRegionFactoryBean cassandraCacheRegion =
new PartitionedRegionFactoryBean();
cassandraCacheRegion.setCache(gemfireCache());
cassandraCacheRegion.setClose(false);
cassandraCacheRegion.setCacheWriter(gemfireToCassandraCacheWriter());
return cassandraCacheRegion;
}
#Bean
GemFireToCassandraCacheWriter gemfireToCassandraCacheWriter(
CassandraOperations cassandraOperations) {
return new GemFireToCassandraCacheWriter(cassandraOperations);
}
Where the GemFireToCassandraCacheWriter would be defined as...
class GemFireToCassandraCacheWriter extends CacheWriterAdapter {
private CassandraOperations cassandraOperations;
// Using constructor injection is better than field injection
GemFireToCassandraCacheWriter(CassandraOperations cassandraOperations) {
this.cassandraOperations = cassandraOperations;
}
public void beforeCreate(EntryEvent<?, ?> event) {
cassandraOperations.insert(event.getNewValue());
}
}
NOTE: a Region can only have 1 CacheWriter. FYI, functionally the CacheWriter is the counterpart to a CacheLoader. See the GemFire User Guide for more details. In particular, see here, here and here.
Additionally, if you are just using GemFire as a cache for state that is primarily managed in Cassandra, then you might also consider Spring's Cache Abstraction, for which Spring Data GemFire positions GemFire as a "provider" in the abstraction.
Not sure what your GemFire to Cassandra UC is all about, but food for thought.
Hope this helps!
-John
Related
I am trying to implement Hibernate second level caching in a Spring boot project using Redisson.
I have followed this blog as a reference
https://pavankjadda.medium.com/implement-hibernate-2nd-level-cache-with-redis-spring-boot-and-spring-data-jpa-7cdbf5632883
Also i am trying to initialize the RedissionClient programmatically and not through declaratively /through a config file
Created a spring bean to be initialized which should create the RedissonClient instance.
#Configuration
#Lazy(value = false)
public class RedissonConfig {
#Bean
public RedissonClient redissionClient() {
Config config = new Config();
config.useSingleServer().setAddress("redis://127.0.0.1:6379");
return Redisson.create(config);
}
}
However this bean is never intialized and i get the following error while application startup.
Caused by: org.hibernate.cache.CacheException: Unable to locate Redisson configuration
at org.redisson.hibernate.RedissonRegionFactory.createRedissonClient(RedissonRegionFactory.java:107) ~[redisson-hibernate-53-3.12.1.jar:3.12.1]
at org.redisson.hibernate.RedissonRegionFactory.prepareForUse(RedissonRegionFactory.java:83) ~[redisson-hibernate-53-3.12.1.jar:3.12.1]
It seems Spring boot Hibernate still trying to load the Redisson config through a config file.
is it possible to load the Redission config in spring boot programmatically ?
Best Regards,
Saurav
I just did exactly this, here is how:
you need a custom RegionFactory that is similar to the JndiRedissonRegionFactory but gets its RedissonClient injected somehow.
an instance of this Class, fully configured, is put into the hibernate-properties map. Hibernates internal code is flexible: if the value of hibernate.cache.region.factory_class is a string it is treated as a FQDN. If it is an instance of Class<?>, it will be instantiated. If it is an Object, it will be used.
Spring offers a rather simple way to customize hibernate properties with a bean:
#AutoConfiguration(after = RedissonAutoConfiguration.class, before = JpaAutoConfiguration.class)
#ConditionalOnProperty("spring.jpa.properties.hibernate.cache.use_second_level_cache")
public class HibernateCacheAutoConfiguration {
#Bean
public HibernatePropertiesCustomizer setRegionFactory(RedissonClient redisson) {
return hibernateProperties -> hibernateProperties.put(AvailableSettings.CACHE_REGION_FACTORY, new SpringBootRedissonRegionFactory(redisson));
}
}
My RegionFactory is really simple:
#AllArgsConstructor
public class SpringBootRedissonRegionFactory extends RedissonRegionFactory {
private RedissonClient redissonClient;
#Override
protected RedissonClient createRedissonClient(Map properties) {
return redissonClient;
}
#Override
protected void releaseFromUse() {
}
}
I used the redisson-starter to get a RedissonClient, hence the reference to RedissonAutoConfiguration, but you could just create an instance by hand.
It is possible, but then you need to provide a custom implementation of RegionFactory to Hibernate, which can extends RedissonRegionFactory but uses your own client instance.
I'm writing an app that talks to one database, obtains credentials for other databases, and connects to the others. It does this using a DataSource and EntityManagerFactory constructed at runtime.
If I want to use Spring Data Repositories, I think I'd need to Autowire them, and therefore they must be Spring Beans.
How can I use Spring Data if I don't have a constructed DataSource until after I run a query against the first database?
I believe that conditional bean creation is your answer. check here.
Also, you have to get the bean after you make sure the conditions are met. check here.
#Component
public class RuntimeBeanBuilder {
#Autowired
private ApplicationContext applicationContext;
public MyObject load(String beanName, MyObject myObject) {
ConfigurableApplicationContext configContext = (ConfigurableApplicationContext) applicationContext;
SingletonBeanRegistry beanRegistry = configContext.getBeanFactory();
if (beanRegistry.containsSingleton(beanName)) {
return beanRegistry.getSingleton(beanName);
} else {
beanRegistry.registerSingleton(beanName, myObject);
return beanRegistry.getSingleton(beanName);
}
}
}
#Service
public MyService{
//inject your builder and create or load beans
#Autowired
private RuntimeBeanBuilder builder;
//do something
}
So, define a bean for your Spring Data Repository and set its condition to be met when the other database credentials are fetched.
And then, reloading the bean using the RuntimeBeanBuilder in your service will get you the bean because now its condition is met.
My goal is to have a have integration tests that ensures that there isn't too many database queries happening during lookups. (This helps us catch n+1 queries due to incorrect JPA configuration)
I know that the database connection is correct because there is no configuration problems during the test run whenever MyDataSourceWrapperConfiguration is not included in the test. However, once it is added, the circular dependency happens. (see error below) I believe #Primary is necessary in order for the JPA/JDBC code to use the correct DataSource instance.
MyDataSourceWrapper is a custom class that tracks the number of queries that have happened for a given transaction, but it delegates the real database work to the DataSource passed in via constructor.
Error:
The dependencies of some of the beans in the application context form a cycle:
org.springframework.boot.autoconfigure.orm.jpa.HibernateJpaAutoConfiguration
┌─────┐
| databaseQueryCounterProxyDataSource defined in me.testsupport.database.MyDataSourceWrapperConfiguration
↑ ↓
| dataSource defined in org.springframework.boot.autoconfigure.jdbc.DataSourceConfiguration$Tomcat
↑ ↓
| dataSourceInitializer
└─────┘
My Configuration:
#Configuration
public class MyDataSourceWrapperConfiguration {
#Primary
#Bean
DataSource databaseQueryCounterProxyDataSource(final DataSource delegate) {
return MyDataSourceWrapper(delegate);
}
}
My Test:
#ActiveProfiles({ "it" })
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration({ DatabaseConnectionConfiguration.class, DatabaseQueryCounterConfiguration.class })
#EnableAutoConfiguration
public class EngApplicationRepositoryIT {
#Rule
public MyDatabaseQueryCounter databaseQueryCounter = new MyDatabaseQueryCounter ();
#Rule
public ErrorCollector errorCollector = new ErrorCollector();
#Autowired
MyRepository repository;
#Test
public void test() {
this.repository.loadData();
this.errorCollector.checkThat(this.databaseQueryCounter.getSelectCounts(), is(lessThan(10)));
}
}
UPDATE: This original question was for springboot 1.5. The accepted answer reflects that, however, the answer from #rajadilipkolli works for springboot 2.x
In your case you will get 2 DataSource instances which is probably not what you want. Instead use BeanPostProcessor which is the component actually designed for this. See also the Spring Reference Guide.
Create and register a BeanPostProcessor which does the wrapping.
public class DataSourceWrapper implements BeanPostProcessor {
public Object postProcessBeforeInitialization(Object bean, String beanName) {
if (bean instanceof DataSource) {
return new MyDataSourceWrapper((DataSource)bean);
}
return bean;
}
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
}
Then just register that as a #Bean instead of your MyDataSourceWrapper.
Tip: Instead of rolling your own wrapping DataSource you might be interested in datasource-proxy combined with datasource-assert which has counter etc. support already (saves you maintaining your own components).
Starting from spring boot 2.0.0.M3 using BeanPostProcessor wont work.
As a work around create your own bean like below
#Bean
public DataSource customDataSource(DataSourceProperties properties) {
log.info("Inside Proxy Creation");
final HikariDataSource dataSource = (HikariDataSource) properties
.initializeDataSourceBuilder().type(HikariDataSource.class).build();
if (properties.getName() != null) {
dataSource.setPoolName(properties.getName());
}
return ProxyDataSourceBuilder.create(dataSource).countQuery().name("MyDS")
.logSlowQueryToSysOut(1, TimeUnit.MINUTES).build();
}
Another way is to use datasource-proxy version of datasource-decorator starter
Following solution works for me using Spring Boot 2.0.6.
It uses explicit binding instead of annotation #ConfigurationProperties(prefix = "spring.datasource.hikari").
#Configuration
public class DataSourceConfig {
private final Environment env;
#Autowired
public DataSourceConfig(Environment env) {
this.env = env;
}
#Primary
#Bean
public MyDataSourceWrapper primaryDataSource(DataSourceProperties properties) {
DataSource dataSource = properties.initializeDataSourceBuilder().build();
Binder binder = Binder.get(env);
binder.bind("spring.datasource.hikari", Bindable.ofInstance(dataSource).withExistingValue(dataSource));
return new MyDataSourceWrapper(dataSource);
}
}
You can actually still use BeanPostProcessor in Spring Boot 2, but it needs to return the correct type (the actual type of the declared Bean). To do this you need to create a proxy of the correct type which redirects DataSource methods to your interceptor and all the other methods to the original bean.
For example code see the Spring Boot issue and discussion at https://github.com/spring-projects/spring-boot/issues/12592.
I have a Hibernate Search ClassBridge where I want to use #Inject to inject a Spring 4.1 managed DAO/Service class. I have annotated the ClassBridge with #Configurable. I noticed that Spring 4.2 adds some additional lifecycle methods that might do the trick, but I'm on Spring 4.1
The goal of this is to store a custom field into the index document based on a query result.
However, since the DAO, depends on the SessionFactory getting initialized, it doesn't get injected because it doesn't exist yet when the #Configurable bean gets processed.
Any suggestions on how to achieve this?
You might try to create a custom field bridge provider, which could get hold of the Spring application context through some static method. When provideFieldBridge() is called you may return a Spring-ified instance of that from the application context, assuming the timing is better and the DAO bean is available by then.
Not sure whether it'd fly, but it may be worth trying.
Hibernate Search 5.8.0 includes support for bean injection. You can see the issue https://hibernate.atlassian.net/browse/HSEARCH-1316.
However I couldn't make it work in my application and I had implemented a workaround.
I have created an application context provider to obtain the Spring application context.
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext context;
public static ApplicationContext getApplicationContext() {
return context;
}
#Override
public void setApplicationContext(ApplicationContext context) throws BeansException {
ApplicationContextProvider.context = context;
}
}
I have added it to the configuration class.
#Configuration
public class RootConfig {
#Bean
public ApplicationContextProvider applicationContextProvider() {
return new ApplicationContextProvider();
}
}
Finally I have used it in a bridge to retrieve the spring beans.
public class AttachmentTikaBridge extends TikaBridge {
#Override
public void set(String name, Object value, Document document, LuceneOptions luceneOptions) {
// get service bean from the application context provider (to be replaced when HS bridges support beans injection)
ApplicationContext applicationContext = ApplicationContextProvider.getApplicationContext();
ExampleService exampleService = applicationContext.getBean(ExampleService .class);
// use exampleService ...
super.set(name, content, document, luceneOptions);
}
}
I think this workaround it's quite simple in comparision with other solutions and it doesn't have any big side effect except the bean injection happens in runtime.
I’m considering to replace the DefaultSessionAttributeStore implementation of Spring MVC 3.2.5 with some class of my own, and I’ve known from the source code that in my 3.2.5 spring source, it’s SessionAttributesHandler which possesses a SessionAttributeStore interface reference and invokes the session store function. My question is how to replace that by DI? The SessionAttributesHandler holds a final private sessionAttributeStore reference and can only be set by the constructor:
public class SessionAttributesHandler {
...
private final SessionAttributeStore sessionAttributeStore;
...
public SessionAttributesHandler(Class<?> handlerType, SessionAttributeStore sessionAttributeStore) {
Assert.notNull(sessionAttributeStore, "SessionAttributeStore may not be null.");
this.sessionAttributeStore = sessionAttributeStore;
SessionAttributes annotation = AnnotationUtils.findAnnotation(handlerType, SessionAttributes.class);
if (annotation != null) {
this.attributeNames.addAll(Arrays.asList(annotation.value()));
this.attributeTypes.addAll(Arrays.<Class<?>>asList(annotation.types()));
}
for (String attributeName : this.attributeNames) {
this.knownAttributeNames.put(attributeName, Boolean.TRUE);
}
}
...
}
Are all the components of spring mvc managed in the spring DI container? How to inject my own SessionAttributeStore implementation into SessionAttributesHandler? What does the "Class handlerType" argument mean in the constructor? From source, it seems like it's the "controller" class. Since SessionAttributesHandler is invoked and held by a ModelFactory, and in ModelFactory there is no code instantiating the SessionAttributesHandler, is there any "XML" bean configuration file for the Spring MVC inner components and how to overwrite them?
If you want to provide your own implementation of a SessionAttributeStore you need to manually configure the RequestMappingHandlerAdapter and set your custom implementation on there. That will take care of using it through-out the rest of the infrastructure.
Assuming that you use java config you can do the following
#Configuration
public class MyConfiguration extend WebMvcConfigurationSupport {
#Bean
public SessionAttributeStore sessionAttributeStore() {
return new MyCustomSessionAttributeStore();
}
#Override
#Bean
public RequestMappingHandlerAdapter requestMappingHandlerAdapter() {
RequestMappingHandlerAdapter rmha = super.requestMappingHandlerAdapter();
rmha.setSessionAttributeStore(sessionAttributeStore());
return rmha;
}
}
If you want to do this in XML you either have to write a BeanPostProcessor which sets it on the default RequestMappingHandlerAdapter instance created by <mvc:annotation-driven /> or configure it manually and drop the namespace support.