org.apache.ignite.cache.query

Class ContinuousQueryWithTransformer<K,V,T>

java.lang.Object

org.apache.ignite.cache.query.Query<javax.cache.Cache.Entry<K,V>>

org.apache.ignite.cache.query.AbstractContinuousQuery<K,V>

org.apache.ignite.cache.query.ContinuousQueryWithTransformer<K,V,T>

All Implemented Interfaces:

Serializable

public final class ContinuousQueryWithTransformer<K,V,T>
extends AbstractContinuousQuery<K,V>

API for configuring continuous cache queries with transformer.

Continuous queries allow to register a remote filter and a local listener for cache updates. If an update event passes the filter, it will be transformed with transformer and sent to the node that executed the query and local listener will be notified.

Additionally, you can execute initial query to get currently existing data. Query can be of any type (SQL, TEXT or SCAN) and can be set via setInitialQuery(Query) method.

Query can be executed either on all nodes in topology using IgniteCache.query(Query) method, or only on the local node, if Query.setLocal(boolean) parameter is set to true. Note that in case query is distributed and a new node joins, it will get the remote filter for the query during discovery process before it actually joins topology, so no updates will be missed. This will execute query on all nodes that have cache you are working with and listener will start to receive notifications for cache updates.

To stop receiving updates call QueryCursor.close() method. Note that this works even if you didn't provide initial query. Cursor will be empty in this case, but it will still unregister listeners when QueryCursor.close() is called.

IgniteAsyncCallback annotation is supported for CacheEntryEventFilter (see setRemoteFilterFactory(Factory)) and CacheEntryUpdatedListener (see setRemoteTransformerFactory(Factory)) and CacheEntryUpdatedListener (see setLocalListener(EventListener) and ContinuousQueryWithTransformer.EventListener). If filter and/or listener are annotated with IgniteAsyncCallback then annotated callback is executed in async callback pool (see IgniteConfiguration.getAsyncCallbackPoolSize()) and notification order is kept the same as update order for given cache key.

See Also:

ContinuousQuery, IgniteAsyncCallback, IgniteConfiguration.getAsyncCallbackPoolSize(), Serialized Form

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	ContinuousQueryWithTransformer.EventListener<T> Interface for local listener of ContinuousQueryWithTransformer to implement.

Field Summary

Fields inherited from class org.apache.ignite.cache.query.AbstractContinuousQuery

DFLT_AUTO_UNSUBSCRIBE, DFLT_PAGE_SIZE, DFLT_TIME_INTERVAL

Constructor Summary

Constructors

Constructor and Description
ContinuousQueryWithTransformer() Creates new continuous query with transformer.

Method Summary

Modifier and Type	Method and Description
ContinuousQueryWithTransformer.EventListener<T>	getLocalListener() Gets local transformed event listener
javax.cache.configuration.Factory<? extends IgniteClosure<javax.cache.event.CacheEntryEvent<? extends K,? extends V>,T>>	getRemoteTransformerFactory() Gets remote transformer factory
ContinuousQueryWithTransformer<K,V,T>	setAutoUnsubscribe(boolean autoUnsubscribe) Sets automatic unsubscribe flag.
ContinuousQueryWithTransformer<K,V,T>	setInitialQuery(Query<javax.cache.Cache.Entry<K,V>> initQry) Sets initial query.
ContinuousQueryWithTransformer<K,V,T>	setLocal(boolean loc) Sets whether this query should be executed on local node only.
ContinuousQueryWithTransformer<K,V,T>	setLocalListener(ContinuousQueryWithTransformer.EventListener<T> locLsnr) Sets local callback.
ContinuousQueryWithTransformer<K,V,T>	setPageSize(int pageSize) Sets optional page size, if 0, then default is used.
ContinuousQueryWithTransformer<K,V,T>	setRemoteFilterFactory(javax.cache.configuration.Factory<? extends javax.cache.event.CacheEntryEventFilter<K,V>> rmtFilterFactory) Sets optional key-value filter factory.
ContinuousQueryWithTransformer<K,V,T>	setRemoteTransformerFactory(javax.cache.configuration.Factory<? extends IgniteClosure<javax.cache.event.CacheEntryEvent<? extends K,? extends V>,T>> factory) Sets transformer factory.
ContinuousQueryWithTransformer<K,V,T>	setTimeInterval(long timeInterval) Sets time interval.

Methods inherited from class org.apache.ignite.cache.query.AbstractContinuousQuery

getInitialQuery, getRemoteFilterFactory, getTimeInterval, isAutoUnsubscribe, isIncludeExpired, setIncludeExpired

Methods inherited from class org.apache.ignite.cache.query.Query

getPageSize, isLocal, prepare, toString

Methods inherited from class java.lang.Object

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

Constructor Detail

ContinuousQueryWithTransformer

public ContinuousQueryWithTransformer()

Creates new continuous query with transformer.

Method Detail

setInitialQuery

public ContinuousQueryWithTransformer<K,V,T> setInitialQuery(Query<javax.cache.Cache.Entry<K,V>> initQry)

Sets initial query.

This query will be executed before continuous listener is registered which allows to iterate through entries which already existed at the time continuous query is executed.

Overrides:

setInitialQuery in class AbstractContinuousQuery<K,V>

Parameters:

initQry - Initial query.

Returns:

this for chaining.

setRemoteFilterFactory

public ContinuousQueryWithTransformer<K,V,T> setRemoteFilterFactory(javax.cache.configuration.Factory<? extends javax.cache.event.CacheEntryEventFilter<K,V>> rmtFilterFactory)

Sets optional key-value filter factory. This factory produces filter is called before entry is sent to the master node.

WARNING: all operations that involve any kind of JVM-local or distributed locking (e.g., synchronization or transactional cache operations), should be executed asynchronously without blocking the thread that called the filter. Otherwise, you can get deadlocks.

If remote filter are annotated with IgniteAsyncCallback then it is executed in async callback pool (see IgniteConfiguration.getAsyncCallbackPoolSize()) that allow to perform a cache operations.

Overrides:

setRemoteFilterFactory in class AbstractContinuousQuery<K,V>

Parameters:

rmtFilterFactory - Key-value filter factory.

Returns:

this for chaining.

See Also:

IgniteAsyncCallback, IgniteConfiguration.getAsyncCallbackPoolSize()

setRemoteTransformerFactory

public ContinuousQueryWithTransformer<K,V,T> setRemoteTransformerFactory(javax.cache.configuration.Factory<? extends IgniteClosure<javax.cache.event.CacheEntryEvent<? extends K,? extends V>,T>> factory)

Sets transformer factory. This factory produces transformer is called after and only if entry passes the filter.

WARNING: all operations that involve any kind of JVM-local or distributed locking (e.g., synchronization or transactional cache operations), should be executed asynchronously without blocking the thread that called the filter. Otherwise, you can get deadlocks.

Parameters:

factory - Remote transformer factory.

Returns:

this for chaining.

getRemoteTransformerFactory

public javax.cache.configuration.Factory<? extends IgniteClosure<javax.cache.event.CacheEntryEvent<? extends K,? extends V>,T>> getRemoteTransformerFactory()

Gets remote transformer factory

Returns:

Remote Transformer Factory

setLocalListener

public ContinuousQueryWithTransformer<K,V,T> setLocalListener(ContinuousQueryWithTransformer.EventListener<T> locLsnr)

Sets local callback. This callback is called only in local node when new updates are received.

The callback predicate accepts results of transformed by AbstractContinuousQuery.getRemoteFilterFactory() events

WARNING: all operations that involve any kind of JVM-local or distributed locking (e.g., synchronization or transactional cache operations), should be executed asynchronously without blocking the thread that called the callback. Otherwise, you can get deadlocks.

If local listener are annotated with IgniteAsyncCallback then it is executed in async callback pool (see IgniteConfiguration.getAsyncCallbackPoolSize()) that allow to perform a cache operations.

Parameters:

locLsnr - Local callback.

Returns:

this for chaining.

See Also:

IgniteAsyncCallback, IgniteConfiguration.getAsyncCallbackPoolSize(), ContinuousQuery.setLocalListener(CacheEntryUpdatedListener)

getLocalListener

public ContinuousQueryWithTransformer.EventListener<T> getLocalListener()

Gets local transformed event listener

Returns:

local transformed event listener

setTimeInterval

public ContinuousQueryWithTransformer<K,V,T> setTimeInterval(long timeInterval)

Sets time interval.

When a cache update happens, entry is first put into a buffer. Entries from buffer will be sent to the master node only if the buffer is full (its size can be provided via Query.setPageSize(int) method) or time provided via this method is exceeded.

Default time interval is 0 which means that time check is disabled and entries will be sent only when buffer is full.

Overrides:

setTimeInterval in class AbstractContinuousQuery<K,V>

Parameters:

timeInterval - Time interval.

Returns:

this for chaining.

setAutoUnsubscribe

public ContinuousQueryWithTransformer<K,V,T> setAutoUnsubscribe(boolean autoUnsubscribe)

Sets automatic unsubscribe flag.

This flag indicates that query filters on remote nodes should be automatically unregistered if master node (node that initiated the query) leaves topology. If this flag is false, filters will be unregistered only when the query is cancelled from master node, and won't ever be unregistered if master node leaves grid.

Default value for this flag is true.

Overrides:

setAutoUnsubscribe in class AbstractContinuousQuery<K,V>

Parameters:

autoUnsubscribe - Automatic unsubscription flag.

Returns:

this for chaining.

setPageSize

public ContinuousQueryWithTransformer<K,V,T> setPageSize(int pageSize)

Sets optional page size, if 0, then default is used.

Overrides:

setPageSize in class Query<javax.cache.Cache.Entry<K,V>>

Parameters:

pageSize - Optional page size.

Returns:

this for chaining.

setLocal

public ContinuousQueryWithTransformer<K,V,T> setLocal(boolean loc)

Sets whether this query should be executed on local node only.

Overrides:

setLocal in class Query<javax.cache.Cache.Entry<K,V>>

Parameters:

loc - Local flag.

Returns:

this for chaining.