Chapter 130. Hazelcast Ringbuffer Component

Available as of Camel version 2.16

Avalaible from Camel 2.16

The Hazelcast ringbuffer component is one of Camel Hazelcast Components which allows you to access Hazelcast ringbuffer. Ringbuffer is a distributed data structure where the data is stored in a ring-like structure. You can think of it as a circular array with a certain capacity. 

130.1. Options

The Hazelcast Ringbuffer component supports 3 options which are listed below.

NameDescriptionDefaultType

hazelcastInstance (advanced)

The hazelcast instance reference which can be used for hazelcast endpoint. If you don’t specify the instance reference, camel use the default hazelcast instance from the camel-hazelcast instance.

 

HazelcastInstance

hazelcastMode (advanced)

The hazelcast mode reference which kind of instance should be used. If you don’t specify the mode, then the node mode will be the default.

node

String

resolveProperty Placeholders (advanced)

Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders.

true

boolean

The Hazelcast Ringbuffer endpoint is configured using URI syntax:

hazelcast-ringbuffer:cacheName

with the following path and query parameters:

130.1.1. Path Parameters (1 parameters):

NameDescriptionDefaultType

cacheName

Required The name of the cache

 

String

130.1.2. Query Parameters (10 parameters):

NameDescriptionDefaultType

reliable (common)

Define if the endpoint will use a reliable Topic struct or not.

false

boolean

defaultOperation (producer)

To specify a default operation to use, if no operation header has been provided.

 

HazelcastOperation

hazelcastInstance (producer)

The hazelcast instance reference which can be used for hazelcast endpoint.

 

HazelcastInstance

hazelcastInstanceName (producer)

The hazelcast instance reference name which can be used for hazelcast endpoint. If you don’t specify the instance reference, camel use the default hazelcast instance from the camel-hazelcast instance.

 

String

synchronous (advanced)

Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported).

false

boolean

concurrentConsumers (seda)

To use concurrent consumers polling from the SEDA queue.

1

int

onErrorDelay (seda)

Milliseconds before consumer continues polling after an error has occurred.

1000

int

pollTimeout (seda)

The timeout used when consuming from the SEDA queue. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.

1000

int

transacted (seda)

If set to true then the consumer runs in transaction mode, where the messages in the seda queue will only be removed if the transaction commits, which happens when the processing is complete.

false

boolean

transferExchange (seda)

If set to true the whole Exchange will be transfered. If header or body contains not serializable objects, they will be skipped.

false

boolean

130.2. ringbuffer cache producer

The ringbuffer producer provides 5 operations: * add * readonceHead * readonceTail * remainingCapacity * capacity

Header Variables for the request message:

NameTypeDescription

CamelHazelcastOperationType

String

valid values are: put, get, removevalue, delete

CamelHazelcastObjectId

String

the object id to store / find your object inside the cache

130.2.1. Sample for put:

Java DSL:

from("direct:put")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastOperation.ADD))
.to(String.format("hazelcast-%sbar", HazelcastConstants.RINGBUFFER_PREFIX));

Spring DSL:

<route>
    <from uri="direct:put" />
    <log message="put.."/>
        <!-- If using version 2.8 and above set headerName to "CamelHazelcastOperationType" -->
    <setHeader headerName="hazelcast.operation.type">
        <constant>add</constant>
    </setHeader>
    <to uri="hazelcast-ringbuffer:foo" />
</route>

130.2.2. Sample for readonce from head:

Java DSL:

from("direct:get")
.setHeader(HazelcastConstants.OPERATION, constant(HazelcastOperation.READ_ONCE_HEAD))
.toF("hazelcast-%sbar", HazelcastConstants.RINGBUFFER_PREFIX)
.to("seda:out");