docs/components/modules/ROOT/pages/grape-component.adoc

[[grape-component]]
= Grape Component
:page-source: components/camel-grape/src/main/docs/grape-component.adoc

*Available as of Camel version 2.16*

http://docs.groovy-lang.org/latest/html/documentation/grape.html[Grape]
component allows you to fetch, load and manage additional jars when
`CamelContext` is running. In practice with Camel Grape component you
can add new components, data formats and beans to your `CamelContext`
without the restart of the router.


== Grape options

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



[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *patchesRepository* (advanced) | Implementation of org.apache.camel.component.grape.PatchesRepository, by default: FilePatchesRepository |  | PatchesRepository
| *basicPropertyBinding* (advanced) | Whether the component should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities | false | boolean
|===
// component options: END


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

----
grape:defaultCoordinates
----

with the following path and query parameters:

=== Path Parameters (1 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| Name | Description | Default | Type
| *defaultCoordinates* | *Required* Maven coordinates to use as default to grab if the message body is empty. |  | String
|===


=== Query Parameters (3 parameters):


[width="100%",cols="2,5,^1,2",options="header"]
|===
| 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
| *basicPropertyBinding* (advanced) | Whether the endpoint should use basic property binding (Camel 2.x) or the newer property binding with additional capabilities | false | boolean
| *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



== Setting up class loader

Grape requires using Groovy class loader with the `CamelContext`. You
can enable Groovy class loading on the existing Camel Context using the
`GrapeComponent#grapeCamelContext()` method:

[source,java]
--------------------------------------------------------------------------------
import static org.apache.camel.component.grape.GrapeComponent.grapeCamelContext;
...
CamelContext camelContext = grapeCamelContext(new DefaultCamelContext());
--------------------------------------------------------------------------------

You can also set up the Groovy class loader used be Camel context by
yourself:

[source,java]
------------------------------------------------------------------------------------
camelContext.setApplicationContextClassLoader(new GroovyClassLoader(myClassLoader));
------------------------------------------------------------------------------------

== URI format

Grape component supports only producer endpoints.

[source,java]
-----------------------------
grape:defaultMavenCoordinates
-----------------------------

For example the following snippet loads Camel FTP component:

[source,java]
------------------------------------------------
from("direct:loadCamelFTP").
  to("grape:org.apache.camel/camel-ftp/2.15.2");
------------------------------------------------

You can also specify the Maven coordinates by sending them to the
endpoint as the exchange body:

[source,java]
----------------------------------------------------------
from("direct:loadCamelFTP").
  setBody().constant("org.apache.camel/camel-ftp/2.15.2").
  to("grape:defaultMavenCoordinates");
----------------------------------------------------------

== Adding the Grape component to the project

Maven users will need to add the following dependency to their `pom.xml`
for this component:

[source,xml]
------------------------------------------------------------
<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-grape</artifactId>
    <version>x.y.z</version>
    <!-- use the same version as your Camel core version -->
</dependency>
------------------------------------------------------------

== Default payload type

By default Camel Grape component operates on the String payloads:

[source,java]
------------------------------------------------------------------------------------------------
producerTemplate.sendBody("grape:defaultMavenCoordinates", "org.apache.camel/camel-ftp/2.15.2");
------------------------------------------------------------------------------------------------

But of course Camel build-in xref:manual::type-converter.adoc[type conversion
API] can perform the automatic data type transformations for you. In the
example below Camel automatically converts binary payload into the
String:

 

[source,java]
-----------------------------------------------------------------------------------------------------------
producerTemplate.sendBody("grape:defaultMavenCoordinates", "org.apache.camel/camel-ftp/2.15.2".getBytes());
-----------------------------------------------------------------------------------------------------------

== Headers

The following headers are recognized by the Grape component:

[width="100%",cols="10%,10%,10%,10%,60%",options="header",]
|=======================================================================
|Header |Java constant |Endpoint type |Value type |Description

|`CamelGrapeCommand` |`GrapeConstants.GRAPE_COMMAND` |Producer |`org.apache.camel.component.grape.GrapeCommand` |The command to be performed by the Grape endpoint. Default to `grab`.
|=======================================================================

== Loading components at runtime

In order to load the new component at the router runtime, just grab the
jar containing the given component:

[source,java]
-------------------------------------------------------------------------
ProducerTemplate template = camelContext.createProducerTemplate();
template.sendBody("grape:grape", "org.apache.camel/camel-stream/2.15.2");
template.sendBody("stream:out", "msg");
-------------------------------------------------------------------------

== Loading processors bean at runtime

In order to load the new processor bean  with your custom business login
at the router runtime, just grab the jar containing the required bean:

[source,java]
-----------------------------------------------------------------------------------------------------------------
ProducerTemplate template = camelContext.createProducerTemplate();
template.sendBody("grape:grape", "com.example/my-business-processors/1.0");
int productId = 1;
int price = template.requestBody("bean:com.example.PricingBean?method=currentProductPrice", productId, int.class)
-----------------------------------------------------------------------------------------------------------------

 

== Loading deployed jars after Camel context restart

After you download new jar, you usually would like to have it loaded by
the Camel again after the restart of the `CamelContext`. It is certainly
possible, as Grape component keeps track of the jar files you have
installed. In order to load again the installed jars on the context
startup, use the `GrapeEndpoint.loadPatches()` method in your route: 

 

[source,java]
-------------------------------------------------------------------------
import static org.apache.camel.component.grape.GrapeEndpoint.loadPatches;

... 
camelContext.addRoutes(
  new RouteBuilder() { 
    @Override 
    public void configure() throws Exception { 
      loadPatches(camelContext);
 
      from("direct:loadCamelFTP").
        to("grape:org.apache.camel/camel-ftp/2.15.2"); 
    }
  });
-------------------------------------------------------------------------

 

== Managing the installed jars

If you would like to check what jars have been installed into the given
`CamelContext`, send message to the grape endpoint with
the `CamelGrapeCommand` header set to `GrapeCommand.listPatches`:

[source,java]
----------------------------------------------------------------------------------------
      from("netty-http:http://0.0.0.0:80/patches").
        setHeader(GrapeConstats.GRAPE_COMMAND, constant(CamelGrapeCommand.listPatches)).
        to("grape:list"); 
----------------------------------------------------------------------------------------

Connecting the to the route defined above using the HTTP client returns
the list of the jars installed by Grape component:

[source,java]
---------------------------------------
$ curl http://my-router.com/patches
grape:org.apache.camel/camel-ftp/2.15.2
grape:org.apache.camel/camel-jms/2.15.2
---------------------------------------

If you would like to remove the installed jars, so these won't be loaded
again after the context restart, use the `GrapeCommand.``clearPatches`
command:

[source,java]
-----------------------------------------------------------------------------------------
      from("netty-http:http://0.0.0.0:80/patches").
        setHeader(GrapeConstats.GRAPE_COMMAND, constant(CamelGrapeCommand.clearPatches)).
        setBody().constant("Installed patches have been deleted."); 
-----------------------------------------------------------------------------------------