com.hazelcast.config

Class ReliableTopicConfig

java.lang.Object

com.hazelcast.config.ReliableTopicConfig

All Implemented Interfaces:

NamedConfig, DataSerializable, IdentifiedDataSerializable

public class ReliableTopicConfig
extends Object
implements IdentifiedDataSerializable, NamedConfig

Configuration for a reliable ITopic.

The reliable topic makes use of a 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()
ReliableTopicConfig(String name) Creates a new ReliableTopicConfig with default settings.

Method Summary

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.
boolean	equals(Object o)
ReliableTopicConfig	getAsReadOnly() Deprecated. this method will be removed in 4.0; it is meant for internal usage only
Executor	getExecutor() Gets the Executor that is going to process the events.
int	getFactoryId() Returns DataSerializableFactory factory ID for this class.
int	getId() Returns type identifier for this class.
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.
int	hashCode()
boolean	isStatisticsEnabled() Checks if statistics are enabled for this reliable topic.
void	readData(ObjectDataInput in) Reads fields from the input stream
ReliableTopicConfig	setExecutor(Executor executor) Sets the executor that is going to process the event.
ReliableTopicConfig	setMessageListenerConfigs(List<ListenerConfig> listenerConfigs) Sets the list of message listeners (listens for when messages are added or removed) for this topic.
ReliableTopicConfig	setName(String name) Sets the name of the reliable topic.
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()
void	writeData(ObjectDataOutput out) Writes object fields to output stream

Methods inherited from class java.lang.Object

clone, finalize, getClass, 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()

ReliableTopicConfig

public ReliableTopicConfig(String name)

Creates a new ReliableTopicConfig with default settings.

Method Detail

setName

public ReliableTopicConfig setName(String name)

Sets the name of the reliable topic.

Specified by:

setName in interface NamedConfig

Parameters:

name - the name of the reliable topic

Returns:

the updated ReliableTopicConfig

Throws:

IllegalArgumentException - if name is null or an empty string

getName

public String getName()

Gets the name of the reliable topic.

Specified by:

getName in interface NamedConfig

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 maximum read batch size can be influenced using the read batch size.

Apart from influencing the number of messages to retrieve, 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 the 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. Collects the creation time, total number of published and received messages for each member locally.

Parameters:

statisticsEnabled - true to enable statistics, false to disable

Returns:

the updated reliable topic config

setMessageListenerConfigs

public ReliableTopicConfig setMessageListenerConfigs(List<ListenerConfig> listenerConfigs)

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

Parameters:

listenerConfigs - the list of message listeners for this topic

Returns:

this updated topic configuration

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

toString

public String toString()

Overrides:

toString in class Object

getAsReadOnly

public ReliableTopicConfig getAsReadOnly()

Deprecated. this method will be removed in 4.0; it is meant for internal usage only

Gets immutable version of this configuration.

Returns:

immutable version of this configuration

getFactoryId

public int getFactoryId()

Description copied from interface: IdentifiedDataSerializable

Returns DataSerializableFactory factory ID for this class.

Specified by:

getFactoryId in interface IdentifiedDataSerializable

Returns:

factory ID

getId

public int getId()

Description copied from interface: IdentifiedDataSerializable

Returns type identifier for this class. It should be unique per DataSerializableFactory.

Specified by:

getId in interface IdentifiedDataSerializable

Returns:

type ID

writeData

public void writeData(ObjectDataOutput out)
               throws IOException

Description copied from interface: DataSerializable

Writes object fields to output stream

Specified by:

writeData in interface DataSerializable

Parameters:

out - output

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the output stream has been closed.

readData

public void readData(ObjectDataInput in)
              throws IOException

Description copied from interface: DataSerializable

Reads fields from the input stream

Specified by:

readData in interface DataSerializable

Parameters:

in - input

Throws:

IOException - if an I/O error occurs. In particular, an IOException may be thrown if the input stream has been closed.

equals

public final boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public final int hashCode()

Overrides:

hashCode in class Object