Chapter 18. Direct
Both producer and consumer are supported
The Direct component provides direct, synchronous invocation of any consumers when a producer sends a message exchange.
This endpoint can be used to connect existing routes in the same camel context.
Asynchronous
The SEDA component provides asynchronous invocation of any consumers when a producer sends a message exchange.
18.1. URI format
direct:someName[?options]
Where someName can be any string to uniquely identify the endpoint
18.2. Configuring Options
Camel components are configured on two separate levels:
- component level
- endpoint level
18.2.1. 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.
18.2.2. 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 as a type safe way of configuring endpoints.
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.
18.3. Component Options
The Direct component supports 5 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 |
18.4. Endpoint Options
The Direct endpoint is configured using URI syntax:
direct:name
with the following path and query parameters:
18.4.1. Path Parameters (1 parameters)
| Name | Description | Default | Type |
|---|---|---|---|
| name (common) | Required Name of direct endpoint. | String |
18.4.2. Query Parameters (8 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 (advanced)) | 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 (advanced)) | Sets the exchange pattern when the consumer creates an exchange. Enum values:
| 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 endpoint with no active consumers. | 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 |
| synchronous (advanced) | Whether synchronous processing is forced. If enabled then the producer thread, will be forced to wait until the message has been completed before the same thread will continue processing. If disabled (default) then the producer thread may be freed and can do other work while the message is continued processed by other threads (reactive). | false | boolean |
18.5. 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:processOrder");
from("direct: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:processOrder"/> </route> <route> <from uri="direct:processOrder"/> <to uri="bean:orderService?method=process"/> <to uri="activemq:queue:order.out"/> </route>
See also samples from the SEDA component, how they can be used together.
18.6. Spring Boot Auto-Configuration
When using direct 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-direct-starter</artifactId>
<version>{CamelSBProjectVersion}</version>
<!-- Use your Camel Spring Boot version -->
</dependency>The component supports 6 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| camel.component.direct.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.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.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.enabled | Whether to enable auto configuration of the direct component. This is enabled by default. | Boolean | |
| camel.component.direct.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.timeout | The timeout value to use if block is enabled. | 30000 | Long |
