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Chapter 137. 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.
137.1. Options
The Hazelcast Ringbuffer component supports 3 options which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| 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:
137.1.1. Path Parameters (1 parameters):
| Name | Description | Default | Type |
|---|---|---|---|
| cacheName | Required The name of the cache | String |
137.1.2. Query Parameters (10 parameters):
| Name | Description | Default | Type |
|---|---|---|---|
| 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 |
137.2. ringbuffer cache producer
The ringbuffer producer provides 5 operations: * add * readonceHead * readonceTail * remainingCapacity * capacity
Header Variables for the request message:
| Name | Type | Description |
|---|---|---|
|
|
| valid values are: put, get, removevalue, delete |
|
|
| the object id to store / find your object inside the cache |
137.2.1. 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>137.2.2. 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");