Package com.hazelcast.config

Class ReliableTopicConfig

  • All Implemented Interfaces:
    NamedConfig, DataSerializable, IdentifiedDataSerializable
    public class ReliableTopicConfig
extends java.lang.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 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​(java.lang.String name)
        Creates a new ReliableTopicConfig with default settings.

      • ReliableTopicConfig

        public ReliableTopicConfig​(ReliableTopicConfig config)
        Creates a new ReliableTopicConfig by cloning an existing one.
        Parameters:
        config - the ReliableTopicConfig to clone

    • Method Detail

      • setName

        public ReliableTopicConfig setName​(java.lang.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:
        java.lang.IllegalArgumentException - if name is null

      • getName

        public java.lang.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:
        java.lang.IllegalArgumentException - if topicOverloadPolicy is null

      • getExecutor

        public java.util.concurrent.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​(java.util.concurrent.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:
        java.lang.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​(java.util.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 java.util.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:
        java.lang.NullPointerException - if listenerConfig is null

      • toString

        public java.lang.String toString()
        Overrides:
        toString in class java.lang.Object

      • writeData

        public void writeData​(ObjectDataOutput out)
               throws java.io.IOException
        Description copied from interface: DataSerializable
        Writes object fields to output stream
        Specified by:
        writeData in interface DataSerializable
        Parameters:
        out - output
        Throws:
        java.io.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 java.io.IOException
        Description copied from interface: DataSerializable
        Reads fields from the input stream
        Specified by:
        readData in interface DataSerializable
        Parameters:
        in - input
        Throws:
        java.io.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​(java.lang.Object o)
        Overrides:
        equals in class java.lang.Object

      • hashCode

        public final int hashCode()
        Overrides:
        hashCode in class java.lang.Object