Direct VM

Since Camel 2.10

Both producer and consumer are supported

The Direct-Vm component provides direct, synchronous invocation of any consumers in the JVM when a producer sends a message exchange.
This endpoint can be used to connect existing routes in the same camel context, as well from other camel contexts in the same JVM.

This component differs from the Direct component in that Direct-VM supports communication across CamelContext instances - so you can use this mechanism to communicate across web applications (provided that camel-core.jar is on the system/boot classpath).

At runtime you can swap in new consumers, by stopping the existing consumer(s) and start new consumers.
But at any given time there can be at most only one active consumer for a given endpoint.

This component allows also to connect routes deployed in different OSGI Bundles as you can see here after. Even if they are running in different bundles, the camel routes will use
the same thread. That autorises to develop applications using Transactions - Tx.

image

URI format

direct-vm:someName

Where someName can be any string to uniquely identify the endpoint

Options

The Direct VM component supports 7 options, which are listed below.

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

block (producer)

If sending a message to a direct endpoint which has no active consumer, then we can tell the producer to block and wait for the consumer to become active.

true

boolean

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

timeout (producer)

The timeout value to use if block is enabled.

30000

long

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

headerFilterStrategy (advanced)

Sets a HeaderFilterStrategy that will only be applied on producer endpoints (on both directions: request and response). Default value: none.

HeaderFilterStrategy

propagateProperties (advanced)

Whether to propagate or not properties from the producer side to the consumer side, and vice versa. Default value: true.

true

boolean

The Direct VM endpoint is configured using URI syntax:

direct-vm:name

with the following path and query parameters:

Path Parameters (1 parameters):

Name Description Default Type

name

Required Name of direct-vm endpoint

String

Query Parameters (9 parameters):

Name Description Default Type

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

exceptionHandler (consumer)

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer)

Sets the exchange pattern when the consumer creates an exchange. There are 3 enums and the value can be one of: InOnly, InOut, InOptionalOut

ExchangePattern

block (producer)

If sending a message to a direct endpoint which has no active consumer, then we can tell the producer to block and wait for the consumer to become active.

true

boolean

failIfNoConsumers (producer)

Whether the producer should fail by throwing an exception, when sending to a Direct-VM endpoint with no active consumers.

false

boolean

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

timeout (producer)

The timeout value to use if block is enabled.

30000

long

headerFilterStrategy (producer)

Sets a HeaderFilterStrategy that will only be applied on producer endpoints (on both directions: request and response). Default value: none.

HeaderFilterStrategy

propagateProperties (advanced)

Whether to propagate or not properties from the producer side to the consumer side, and vice versa. Default value: true.

true

boolean

Samples

In the route below we use the direct component to link the two routes together:

from("activemq:queue:order.in")
    .to("bean:orderServer?method=validate")
    .to("direct-vm:processOrder");

And now in another CamelContext, such as another OSGi bundle

from("direct-vm:processOrder")
    .to("bean:orderService?method=process")
    .to("activemq:queue:order.out");

And the sample using spring DSL:

<route>
 <from uri="activemq:queue:order.in"/>
 <to uri="bean:orderService?method=validate"/>
 <to uri="direct-vm:processOrder"/>
</route>

<route>
 <from uri="direct-vm:processOrder"/>
 <to uri="bean:orderService?method=process"/>
 <to uri="activemq:queue:order.out"/>
</route>

Spring Boot Auto-Configuration

When using direct-vm with Spring Boot make sure to use the following Maven dependency to have support for auto configuration:

<dependency>
  <groupId>org.apache.camel.springboot</groupId>
  <artifactId>camel-directvm-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 8 options, which are listed below.

Name Description Default Type

camel.component.direct-vm.autowired-enabled

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

camel.component.direct-vm.block

If sending a message to a direct endpoint which has no active consumer, then we can tell the producer to block and wait for the consumer to become active.

true

Boolean

camel.component.direct-vm.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.direct-vm.enabled

Whether to enable auto configuration of the direct-vm component. This is enabled by default.

Boolean

camel.component.direct-vm.header-filter-strategy

Sets a HeaderFilterStrategy that will only be applied on producer endpoints (on both directions: request and response). Default value: none. The option is a org.apache.camel.spi.HeaderFilterStrategy type.

HeaderFilterStrategy

camel.component.direct-vm.lazy-start-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

camel.component.direct-vm.propagate-properties

Whether to propagate or not properties from the producer side to the consumer side, and vice versa. Default value: true.

true

Boolean

camel.component.direct-vm.timeout

The timeout value to use if block is enabled.

30000

Long
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