Hazelcast Ringbuffer

Since Camel 2.16

Only producer is supported

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.

Configuring Options

Camel components are configured on two separate levels:

  • component level

  • endpoint level

Configuring Component Options

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. For example a component may have security settings, credentials for authentication, urls for network connection and so forth.

Some components only have a few options, and others may have many. Because components typically have pre configured defaults that are commonly used, then you may often only need to configure a few options on a component; or none at all.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL and DataFormat DSL as a type safe way of configuring endpoints and data formats in Java.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists all the options, firstly for the component followed by the endpoint.

Component Options

The Hazelcast Ringbuffer component supports 4 options, which are listed below.

Name Description Default Type

lazyStartProducer (producer)

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

autowiredEnabled (advanced)

Whether autowiring is enabled. This is used for automatic autowiring options (the option must be marked as autowired) by looking up in the registry to find if there is a single instance of matching type, which then gets configured on the component. This can be used for automatic configuring JDBC data sources, JMS connection factories, AWS Clients, etc.

true

boolean

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

Endpoint Options

The Hazelcast Ringbuffer endpoint is configured using URI syntax:

hazelcast-ringbuffer:cacheName

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

cacheName (producer)

Required The name of the cache.

String

Query Parameters (5 parameters)

Name Description Default Type

defaultOperation (producer)

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

Enum values:

  • put

  • delete

  • get

  • update

  • query

  • getAll

  • clear

  • putIfAbsent

  • addAll

  • removeAll

  • retainAll

  • evict

  • evictAll

  • valueCount

  • containsKey

  • containsValue

  • getKeys

  • removeValue

  • increment

  • decrement

  • setValue

  • destroy

  • compareAndSet

  • getAndAdd

  • add

  • offer

  • peek

  • poll

  • remainingCapacity

  • drainTo

  • removeIf

  • take

  • publish

  • readOnceHead

  • readOnceTail

  • capacity

HazelcastOperation

hazelcastConfigUri (producer)

Hazelcast configuration file.

String

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

lazyStartProducer (producer (advanced))

Whether the producer should be started lazy (on the first message). By starting lazy you can use this to allow CamelContext and routes to startup in situations where a producer may otherwise fail during starting and cause the route to fail being started. By deferring this startup to be lazy then the startup failure can be handled during routing messages via Camel’s routing error handlers. Beware that when the first message is processed then creating and starting the producer may take a little time and prolong the total processing time of the processing.

false

boolean

ringbuffer cache producer

The ringbuffer producer provides 5 operations:

  • add

  • readOnceHead

  • readOnceTail

  • remainingCapacity

  • capacity

Message Headers

The Hazelcast Ringbuffer component supports 1 message header(s), which is/are listed below:

Name Description Default Type

CamelHazelcastOperationType (producer)

Constant: OPERATION

The operation to perform.

String

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.."/>
    <setHeader name="hazelcast.operation.type">
        <constant>add</constant>
    </setHeader>
    <to uri="hazelcast-ringbuffer:foo" />
</route>

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");