Chapter 10. Bean
Only producer is supported
The Bean component binds beans to Camel message exchanges.
10.1. URI format
bean:beanName[?options]
Where beanID can be any string which is used to look up the bean in the Registry
10.2. Configuring Options
Camel components are configured on two separate levels:
- component level
- endpoint level
10.2.1. 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.
10.2.2. 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.
10.3. Component Options
The Bean 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 | 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 |
10.4. Endpoint Options
The Bean endpoint is configured using URI syntax:
bean:beanName
with the following path and query parameters:
10.4.1. Path Parameters (1 parameters)
| Name | Description | Default | Type |
|---|---|---|---|
| beanName (common) | Required Sets the name of the bean to invoke. | String |
10.4.2. 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 | BeanScope |
| 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 |
| parameters (advanced) | Used for configuring additional properties on the bean. | Map |
10.5. Using
The object instance that is used to consume messages must be explicitly registered with the Registry. For example, if you are using Spring you must define the bean in the Spring configuration XML file.
You can also register beans manually via Camel’s Registry with the bind method.
Once an endpoint has been registered, you can build Camel routes that use it to process exchanges.
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. So consider using a direct: or queue: endpoint as the input.
You can use the createProxy() methods on ProxyHelper to create a proxy that will generate exchanges and send them to any endpoint:
And the same route using XML DSL:
<route> <from uri="direct:hello"/> <to uri="bean:bye"/> </route>
10.6. Bean as endpoint
Camel also supports invoking Bean as an Endpoint. What happens is that when the exchange is routed to the myBean Camel will use the Bean Binding to invoke the bean. The source for the bean is just a plain POJO.
Camel will use Bean Binding to invoke the sayHello method, by converting the Exchange’s In body to the String type and storing the output of the method on the Exchange Out body.
10.7. Java DSL bean syntax
Java DSL comes with syntactic sugar for the 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);10.8. 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 of the various Bean Integration mechanisms in Camel.
10.9. Spring Boot Auto-Configuration
When using bean 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-bean-starter</artifactId>
<version>{CamelSBProjectVersion}</version>
<!-- use the same version as your Camel core version -->
</dependency>The component supports 13 options, which are listed below.
| Name | Description | Default | Type |
|---|---|---|---|
| camel.component.bean.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.bean.enabled | Whether to enable auto configuration of the bean component. This is enabled by default. | Boolean | |
| camel.component.bean.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.bean.scope | 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. | BeanScope | |
| camel.component.class.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.class.enabled | Whether to enable auto configuration of the class component. This is enabled by default. | Boolean | |
| camel.component.class.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.class.scope | 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. | BeanScope | |
| camel.language.bean.enabled | Whether to enable auto configuration of the bean language. This is enabled by default. | Boolean | |
| camel.language.bean.scope | 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 scope then this depends on the bean registry implementation. | Singleton | String |
| camel.language.bean.trim | Whether to trim the value to remove leading and trailing whitespaces and line breaks. | true | Boolean |
| camel.component.bean.cache | Deprecated Use singleton option instead. | true | Boolean |
| camel.component.class.cache | Deprecated Use singleton option instead. | true | Boolean |
