[[bean-component]]
== Bean Component

*Available as of Camel version 1.0*

The *bean:* component binds beans to Camel message exchanges.

=== URI format

[source]
----
bean:beanName[?options]
----

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

=== Options


// component options: START
The Bean component supports 2 options, which are listed below.



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|===
| Name | Description | Default | Type
| *cache* (advanced) | If enabled, Camel will cache the result of the first Registry look-up. Cache can be enabled if the bean in the Registry is defined as a singleton scope. |  | Boolean
| *resolveProperty Placeholders* (advanced) | Whether the component should resolve property placeholders on itself when starting. Only properties which are of String type can use property placeholders. | true | boolean
|===
// component options: END



// endpoint options: START
The Bean endpoint is configured using URI syntax:

----
bean:beanName
----

with the following path and query parameters:

==== Path Parameters (1 parameters):


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|===
| Name | Description | Default | Type
| *beanName* | *Required* Sets the name of the bean to invoke |  | String
|===


==== Query Parameters (5 parameters):


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|===
| Name | Description | Default | Type
| *method* (producer) | Sets the name of the method to invoke on the bean |  | String
| *cache* (advanced) | If enabled, Camel will cache the result of the first Registry look-up. Cache can be enabled if the bean in the Registry is defined as a singleton scope. |  | Boolean
| *multiParameterArray* (advanced) | *Deprecated* How to treat the parameters which are passed from the message body; if it is true, the message body should be an array of parameters. Note: This option is used internally by Camel, and is not intended for end users to use. Deprecation note: This option is used internally by Camel, and is not intended for end users to use. | false | boolean
| *parameters* (advanced) | Used for configuring additional properties on the bean |  | Map
| *synchronous* (advanced) | Sets whether synchronous processing should be strictly used, or Camel is allowed to use asynchronous processing (if supported). | false | boolean
|===
// endpoint options: END


You can append query options to the URI in the following format,
`?option=value&option=value&...`

=== 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,
`spring.xml`; or if you don't use Spring, by registering the bean in
JNDI.

Error formatting macro: snippet: java.lang.IndexOutOfBoundsException:
Index: 20, Size: 20

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
http://camel.apache.org/maven/current/camel-core/apidocs/org/apache/camel/component/bean/ProxyHelper.html[ProxyHelper]
to create a proxy that will generate BeanExchanges and send them to any
endpoint:

And the same route using Spring DSL:

[source,xml]
----------------------------
<route>
   <from uri="direct:hello">
   <to uri="bean:bye"/>
</route>
----------------------------

=== Bean as endpoint

Camel also supports invoking <<bean-component,Bean>> as an Endpoint. In the
route below:

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.

=== Java DSL bean syntax

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

[source,java]
-------------------------------------------------------
// Send message to the bean endpoint
// and invoke method resolved using Bean Binding.
from("direct:start").beanRef("beanName");

// Send message to the bean endpoint
// and invoke given method.
from("direct:start").beanRef("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:

[source,java]
---------------------------------------------------------------
// 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);
---------------------------------------------------------------

=== 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.

=== See Also

* Configuring Camel
* Component
* Endpoint
* Getting Started

* <<class-component,Class>> component
* Bean Binding
* Bean Integration
