Bean

Since Camel 1.0

Only producer is supported

The Bean component binds beans to Camel message exchanges.

URI format

bean:beanName[?options]

Where beanName can be any string which is used to look up the bean in the Registry

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 Bean 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

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

beanInfoCacheSize (advanced)

Maximum cache size of internal cache for bean introspection. Setting a value of 0 or negative will disable the cache.

1000

int

Endpoint Options

The Bean endpoint is configured using URI syntax:

bean: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 (4 parameters)

Name Description Default Type

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 Bean 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

Examples

A bean: endpoint cannot be defined as the input to the route; i.e. you cannot consume from it, you can only route from some inbound message Endpoint to the bean endpoint as output, such as the direct endpoint as input.

Suppose you have the following POJO class to be used by Camel

package com.foo;

public class MyBean {

    public String saySomething(String input) {
        return "Hello " + input;
    }
}

Then the bean can be called in a Camel route by the fully qualified classname:

from("direct:hello")
   .to("bean:com.foo.MyBean");

And in XML DSL:

<route>
   <from uri="direct:hello"/>
   <to uri="bean:com.foo.MyBean"/>
</route>

What happens is that when the exchange is routed to the MyBean, then Camel will use the Bean Binding to invoke the bean, in this case the saySomething method, by converting the Exchange in body to the String type and storing the output of the method back to the Exchange again.

The bean component can also call a bean by bean id by looking up the bean in the Registry instead of using the class name.

Java DSL specific bean syntax

Java DSL comes with syntactic sugar for the Bean component. Instead of specifying the bean explicitly as the endpoint (i.e. to("bean:beanName")) you can use the following syntax:

// Send message to the bean endpoint
// and invoke method resolved using Bean Binding.
from("direct:start").bean("beanName");

// Send message to the bean endpoint
// and invoke given method.
from("direct:start").bean("beanName", "methodName");

Instead of passing name of the reference to the bean (so that Camel will lookup for it in the Registry), you can specify the bean itself:

// Send message to the given bean instance.
from("direct:start").bean(new ExampleBean());

// Explicit selection of bean method to be invoked.
from("direct:start").bean(new ExampleBean(), "methodName");

// Camel will create the instance of bean and cache it for you.
from("direct:start").bean(ExampleBean.class);

This bean could be a lambda if you cast the lambda to a @FunctionalInterface

@FunctionalInterface
public interface ExampleInterface() {
    @Handler String methodName();
}

from("direct:start")
    .bean((ExampleInterface) () -> ""))

Bean Binding

How bean methods to be invoked are chosen (if they are not specified explicitly through the method parameter) and how parameter values are constructed from the Message are all defined by the Bean Binding mechanism which is used throughout all the various Bean Integration mechanisms in Camel.

See also related Bean Language.