Direct VM Component

Table of Contents

URI format
Options
Samples
See Also

Available as of Camel 2.10

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.

URI format

direct-vm:someName

Where someName can be any string to uniquely identify the endpoint

Options

The Direct VM component supports 4 options which are listed below.

{% raw %}

Name	Java Type	Description
block	`boolean`	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.
timeout	`long`	The timeout value to use if block is enabled.
headerFilterStrategy	`HeaderFilterStrategy`	Sets a HeaderFilterStrategy that will only be applied on producer endpoints (on both directions: request and response). Default value: none.
propagateProperties	`boolean`	Whether to propagate or not properties from the producer side to the consumer side and viceversa. Default value: true.

{% endraw %}

The Direct VM component supports 10 endpoint options which are listed below:

{% raw %}

Name	Group	Default	Java Type	Description
name	common		`String`	Required Name of direct-vm endpoint
bridgeErrorHandler	consumer	`false`	`boolean`	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/ERROR level and ignored.
exceptionHandler	consumer (advanced)		`ExceptionHandler`	To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this options is not in use. By default the consumer will deal with exceptions that will be logged at WARN/ERROR level and ignored.
exchangePattern	consumer (advanced)		`ExchangePattern`	Sets the default exchange pattern when creating an exchange.
block	producer	`false`	`boolean`	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.
failIfNoConsumers	producer	`false`	`boolean`	Whether the producer should fail by throwing an exception when sending to a Direct-VM endpoint with no active consumers.
timeout	producer	`30000`	`long`	The timeout value to use if block is enabled.
headerFilterStrategy	producer (advanced)		`HeaderFilterStrategy`	Sets a HeaderFilterStrategy that will only be applied on producer endpoints (on both directions: request and response). Default value: none.
propagateProperties	advanced	`false`	`Boolean`	Whether to propagate or not properties from the producer side to the consumer side and viceversa. Default value: true.
synchronous	advanced	`false`	`boolean`	Sets whether synchronous processing should be strictly used or Camel is allowed to use asynchronous processing (if supported).

{% endraw %}

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>