Class

Since Camel 2.4

Only producer is supported

The Class component binds beans to Camel message exchanges. It works in the same way as the Bean component but instead of looking up beans from a Registry it creates the bean based on the class name.

URI format

class:className[?options]

Where className is the fully qualified class name to create and use as bean.

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 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.

Component Options

The Class component supports 4 options, which are listed below.

Name Description Default Type

cache (producer)

Deprecated Use singleton option instead.

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

scope (producer)

Scope of bean. When using singleton scope (default) the bean is created or looked up only once and reused for the lifetime of the endpoint. The bean should be thread-safe in case concurrent threads is calling the bean at the same time. When using request scope the bean is created or looked up once per request (exchange). This can be used if you want to store state on a bean while processing a request and you want to call the same bean instance multiple times while processing the request. The bean does not have to be thread-safe as the instance is only called from the same request. When using delegate scope, then the bean will be looked up or created per call. However in case of lookup then this is delegated to the bean registry such as Spring or CDI (if in use), which depends on their configuration can act as either singleton or prototype scope. so when using prototype then this depends on the delegated registry.

Enum values:

  • Singleton

  • Request

  • Prototype

Singleton

BeanScope

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

Endpoint Options

The Class endpoint is configured using URI syntax:

class:beanName

with the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

beanName (common)

Required Sets the name of the bean to invoke.

String

Query Parameters (5 parameters)

Name Description Default Type

cache (common)

Deprecated Use scope option instead.

Boolean

method (common)

Sets the name of the method to invoke on the bean.

String

scope (common)

Scope of bean. When using singleton scope (default) the bean is created or looked up only once and reused for the lifetime of the endpoint. The bean should be thread-safe in case concurrent threads is calling the bean at the same time. When using request scope the bean is created or looked up once per request (exchange). This can be used if you want to store state on a bean while processing a request and you want to call the same bean instance multiple times while processing the request. The bean does not have to be thread-safe as the instance is only called from the same request. When using prototype scope, then the bean will be looked up or created per call. However in case of lookup then this is delegated to the bean registry such as Spring or CDI (if in use), which depends on their configuration can act as either singleton or prototype scope. so when using prototype then this depends on the delegated registry.

Enum values:

  • Singleton

  • Request

  • Prototype

Singleton

BeanScope

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

parameters (advanced)

Used for configuring additional properties on the bean.

Map

Message Headers

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

Name Description Default Type

CamelBeanMethodName (producer)

Constant: BEAN_METHOD_NAME

The name of the method to invoke.

String

Using

You simply use the class component just as the Bean component but by specifying the fully qualified classname instead.
For example to use the MyFooBean you have to do as follows:

    from("direct:start").to("class:org.apache.camel.component.bean.MyFooBean").to("mock:result");

You can also specify which method to invoke on the MyFooBean, for example hello:

    from("direct:start").to("class:org.apache.camel.component.bean.MyFooBean?method=hello").to("mock:result");

Setting properties on the created instance

In the endpoint uri you can specify properties to set on the created instance, for example if it has a setPrefix method:

   from("direct:start")
        .to("class:org.apache.camel.component.bean.MyPrefixBean?bean.prefix=Bye")
        .to("mock:result");

And you can also use the # syntax to refer to properties to be looked up in the Registry.

    from("direct:start")
        .to("class:org.apache.camel.component.bean.MyPrefixBean?bean.cool=#foo")
        .to("mock:result");

Which will lookup a bean from the Registry with the id foo and invoke the setCool method on the created instance of the MyPrefixBean class.

See more details at the Bean component as the class component works in much the same way.