com.hazelcast.config

Class ReliableTopicConfig

java.lang.Object

com.hazelcast.config.ReliableTopicConfig

@Beta
public class ReliableTopicConfig
extends Object

Configuration for a reliable ITopic. The reliable topic makes use of the Ringbuffer to store the actual messages. To configure the ringbuffer for a reliable topic, define a ringbuffer in the config with exactly the same name. It is very unlikely that you want to run with the default settings. When a ReliableTopic starts, it will always start from the tail+1 item from the RingBuffer. It will not chew its way through all available events but it will wait for the next item being published. In the reliable topic, global order is always maintained, so all listeners will observe exactly the same order of sequence of messages.

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_READ_BATCH_SIZE The default read batch size.
static boolean	DEFAULT_STATISTICS_ENABLED Default value for statistics enabled.
static TopicOverloadPolicy	DEFAULT_TOPIC_OVERLOAD_POLICY The default slow consumer policy.

Constructor Summary

Constructors

Constructor and Description
ReliableTopicConfig(String name) Creates a new ReliableTopicConfig with default settings.

Method Summary

Methods

Modifier and Type	Method and Description
ReliableTopicConfig	addMessageListenerConfig(ListenerConfig listenerConfig) Adds a message listener (listens for when messages are added or removed) to this reliable topic.
ReliableTopicConfig	getAsReadOnly() Returns a readonly version of the ReliableTopicConfig.
Executor	getExecutor() Gets the Executor that is going to process the events.
List<ListenerConfig>	getMessageListenerConfigs() Gets the list of message listeners (listens for when messages are added or removed) for this reliable topic.
String	getName() Gets the name of the reliable topic.
int	getReadBatchSize() Gets the maximum number of items to read in a batch.
TopicOverloadPolicy	getTopicOverloadPolicy() Gets the TopicOverloadPolicy for this reliable topic.
boolean	isStatisticsEnabled() Checks if statistics are enabled for this reliable topic.
ReliableTopicConfig	setExecutor(Executor executor) Sets the Executor that is going to process the event.
ReliableTopicConfig	setReadBatchSize(int readBatchSize) Sets the read batch size.
ReliableTopicConfig	setStatisticsEnabled(boolean statisticsEnabled) Enables or disables statistics for this reliable topic..
ReliableTopicConfig	setTopicOverloadPolicy(TopicOverloadPolicy topicOverloadPolicy) Sets the TopicOverloadPolicy for this reliable topic.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_READ_BATCH_SIZE

public static final int DEFAULT_READ_BATCH_SIZE

The default read batch size.

See Also:

Constant Field Values

DEFAULT_TOPIC_OVERLOAD_POLICY

public static final TopicOverloadPolicy DEFAULT_TOPIC_OVERLOAD_POLICY

The default slow consumer policy.

DEFAULT_STATISTICS_ENABLED

public static final boolean DEFAULT_STATISTICS_ENABLED

Default value for statistics enabled.

See Also:

Constant Field Values

Constructor Detail

ReliableTopicConfig

public ReliableTopicConfig(String name)

Creates a new ReliableTopicConfig with default settings.

Method Detail

getName

public String getName()

Gets the name of the reliable topic.

Returns:

the name of the reliable topic.

getTopicOverloadPolicy

public TopicOverloadPolicy getTopicOverloadPolicy()

Gets the TopicOverloadPolicy for this reliable topic.

Returns:

the TopicOverloadPolicy.

setTopicOverloadPolicy

public ReliableTopicConfig setTopicOverloadPolicy(TopicOverloadPolicy topicOverloadPolicy)

Sets the TopicOverloadPolicy for this reliable topic. Check the TopicOverloadPolicy for more details about this setting.

Parameters:

topicOverloadPolicy - the new TopicOverloadPolicy.

Returns:

the updated reliable topic config.

Throws:

IllegalArgumentException - if topicOverloadPolicy is null.

getExecutor

public Executor getExecutor()

Gets the Executor that is going to process the events. If no Executor is selected, then the ExecutionService.ASYNC_EXECUTOR is used.

Returns:

the Executor used to process events.

See Also:

setExecutor(java.util.concurrent.Executor)

setExecutor

public ReliableTopicConfig setExecutor(Executor executor)

Sets the Executor that is going to process the event. In some cases it is desirable to set a specific Executor. For example, you may want to isolate a certain topic from other topics because it contains long running messages or very high priority messages. A single Executor can be shared between multiple Reliable topics, although it could take more time to process a message. If a single Executor is not shared with other reliable topics, then the Executor only needs to have a single thread.

Parameters:

executor - the Executor. if the executor is null, the ExecutionService.ASYNC_EXECUTOR will be used to process the event.

Returns:

the updated config.

getReadBatchSize

public int getReadBatchSize()

Gets the maximum number of items to read in a batch. Returned value will always be equal or larger than 1.

Returns:

the read batch size.

setReadBatchSize

public ReliableTopicConfig setReadBatchSize(int readBatchSize)

Sets the read batch size. The ReliableTopic tries to read a batch of messages from the ringbuffer. It will get at least one, but if there are more available, then it will try to get more to increase throughput. The minimal read batch size can be influenced using the read batch size. Apart from influencing the number of messages to download, the readBatchSize also determines how many messages will be processed by the thread running the MessageListener before it returns back to the pool to look for other MessageListeners that need to be processed. The problem with returning to the pool and looking for new work is that interacting with an Executor is quite expensive due to contention on the work-queue. The more work that can be done without retuning to the pool, the smaller the overhead. If the readBatchSize is 10 and there are 50 messages available, 10 items are retrieved and processed consecutively before the thread goes back to the pool and helps out with the processing of other messages. If the readBatchSize is 10 and there are 2 items available, 2 items are retrieved and processed consecutively. If the readBatchSize is an issue because a thread will be busy too long with processing a single MessageListener and it can't help out other MessageListeners, increase the size of the threadpool so the other MessageListeners don't need to wait for a thread, but can be processed in parallel.

Parameters:

readBatchSize - the maximum number of items to read in a batch.

Returns:

the updated reliable topic config.

Throws:

IllegalArgumentException - if readBatchSize is smaller than 1.

isStatisticsEnabled

public boolean isStatisticsEnabled()

Checks if statistics are enabled for this reliable topic.

Returns:

true if enabled, false otherwise.

setStatisticsEnabled

public ReliableTopicConfig setStatisticsEnabled(boolean statisticsEnabled)

Enables or disables statistics for this reliable topic..

Parameters:

statisticsEnabled - true to enable statistics, false to disable.

Returns:

the updated reliable topic config.

getMessageListenerConfigs

public List<ListenerConfig> getMessageListenerConfigs()

Gets the list of message listeners (listens for when messages are added or removed) for this reliable topic.

Returns:

list of MessageListener configurations.

addMessageListenerConfig

public ReliableTopicConfig addMessageListenerConfig(ListenerConfig listenerConfig)

Adds a message listener (listens for when messages are added or removed) to this reliable topic.

Parameters:

listenerConfig - the ListenerConfig to add.

Returns:

the updated config.

Throws:

NullPointerException - if listenerConfig is null.

getAsReadOnly

public ReliableTopicConfig getAsReadOnly()

Returns a readonly version of the ReliableTopicConfig.

Returns:

a readonly version of this reliable topic config.

toString

public String toString()

Overrides:

toString in class Object