JOLT
Since Camel 2.16
Only producer is supported
The Jolt component allows you to process a JSON messages using a JOLT specification. This can be ideal when doing JSON to JSON transformation.
Maven users will need to add the following dependency to their pom.xml
for this component:
<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-jolt</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>
URI format
jolt:specName[?options]
Where specName
is the classpath-local URI of the specification to invoke; or the complete URL of the remote specification (e.g.: file://folder/myfile.vm
).
Configuring Options
Camel components are configured on two separate levels:
-
component level
-
endpoint level
Configuring Component Options
At the component level, you set general and shared configurations that are, then, inherited by the endpoints. It is the highest configuration level.
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.
You can configure components using:
-
the Component DSL.
-
in a configuration file (
application.properties
,*.yaml
files, etc). -
directly in the Java code.
Configuring Endpoint Options
You usually spend more time setting up endpoints because they have many options. These options help you customize what you want the endpoint to do. The options are also categorized into whether the endpoint is used as a consumer (from), as a producer (to), or 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.
Property placeholders provide a few benefits:
-
They help prevent using hardcoded urls, port numbers, sensitive information, and other settings.
-
They allow externalizing the configuration from the code.
-
They help the code to become more flexible and reusable.
The following two sections list all the options, firstly for the component followed by the endpoint.
Component Options
The JOLT component supports 4 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
Whether to allow to use resource template from header or not (default false). Enabling this allows to specify dynamic templates via message header. However this can be seen as a potential security vulnerability if the header is coming from a malicious user, so use this with care. | false | boolean | |
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 | |
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 | |
Explicitly sets the Transform to use. If not set a Transform specified by the transformDsl will be created. | Transform |
Endpoint Options
The JOLT endpoint is configured using URI syntax:
jolt:resourceUri
With the following path and query parameters:
Path Parameters (1 parameters)
Name | Description | Default | Type |
---|---|---|---|
Required Path to the resource. You can prefix with: classpath, file, http, ref, or bean. classpath, file and http loads the resource using these protocols (classpath is default). ref will lookup the resource in the registry. bean will call a method on a bean to be used as the resource. For bean you can specify the method name after dot, eg bean:myBean.myMethod. | String |
Query Parameters (6 parameters)
Name | Description | Default | Type |
---|---|---|---|
Whether to allow to use resource template from header or not (default false). Enabling this allows to specify dynamic templates via message header. However this can be seen as a potential security vulnerability if the header is coming from a malicious user, so use this with care. | false | boolean | |
Sets whether to use resource content cache or not. | false | boolean | |
Specifies if the input is hydrated JSON or a JSON String. Enum values:
| Hydrated | JoltInputOutputType | |
Specifies if the output should be hydrated JSON or a JSON String. Enum values:
| Hydrated | JoltInputOutputType | |
Specifies the Transform DSL of the endpoint resource. If none is specified Chainr will be used. Enum values:
| Chainr | JoltTransformType | |
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 |
Message Headers
The JOLT component supports 2 message header(s), which is/are listed below:
Name | Description | Default | Type |
---|---|---|---|
CamelJoltResourceUri (producer) Constant: | The resource URI. | String | |
Constant: | The context. | Map |
Examples
For example, you could use something like
from("activemq:My.Queue").
to("jolt:com/acme/MyResponse.json");
And a file-based resource:
from("activemq:My.Queue").
to("jolt:file://myfolder/MyResponse.json?contentCache=true").
to("activemq:Another.Queue");
You can also specify what specification the component should use dynamically via a header, so, for example:
from("direct:in").
setHeader("CamelJoltResourceUri").constant("path/to/my/spec.json").
to("jolt:dummy?allowTemplateFromHeader=true");
Spring Boot Auto-Configuration
When using jolt 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-jolt-starter</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>
The component supports 5 options, which are listed below.
Name | Description | Default | Type |
---|---|---|---|
Whether to allow to use resource template from header or not (default false). Enabling this allows to specify dynamic templates via message header. However this can be seen as a potential security vulnerability if the header is coming from a malicious user, so use this with care. | false | Boolean | |
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 | |
Whether to enable auto configuration of the jolt component. This is enabled by default. | Boolean | ||
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 | |
Explicitly sets the Transform to use. If not set a Transform specified by the transformDsl will be created. The option is a com.bazaarvoice.jolt.Transform type. | Transform |