JQ

Since Camel 3.18

Camel supports JQ to allow using Expression or Predicate on JSON messages.

JQ Options

The JQ language supports 4 options, which are listed below.

Name Default Java Type Description

Name	Default	Java Type	Description
headerName		`String`	Name of header to use as input, instead of the message body It has as higher precedent than the propertyName if both are set.
propertyName		`String`	Name of property to use as input, instead of the message body. It has a lower precedent than the headerName if both are set.
resultType		`String`	Sets the class of the result type (type from output).
trim	`true`	`Boolean`	Whether to trim the value to remove leading and trailing whitespaces and line breaks.

headerName

String

Name of header to use as input, instead of the message body It has as higher precedent than the propertyName if both are set.

propertyName

String

Name of property to use as input, instead of the message body. It has a lower precedent than the headerName if both are set.

resultType

String

Sets the class of the result type (type from output).

trim

true

Boolean

Whether to trim the value to remove leading and trailing whitespaces and line breaks.

Examples

For example, you can use JQ in a Predicate with the Content Based Router EIP.

from("queue:books.new")
  .choice()
    .when().jq(".store.book.price < 10)")
      .to("jms:queue:book.cheap")
    .when().jq(".store.book.price < 30)")
      .to("jms:queue:book.average")
    .otherwise()
      .to("jms:queue:book.expensive");

Message body types

Camel JQ leverages camel-jackson for type conversion. To enable camel-jackson POJO type conversion, refer to the Camel Jackson documentation.

Using header as input

By default, JQ uses the message body as the input source. However, you can also use a header as input by specifying the headerName option.

For example to count the number of books from a JSON document that was stored in a header named books you can do:

from("direct:start")
    .setHeader("numberOfBooks")
        .jq(".store.books | length", int.class, "books")
    .to("mock:result");

Camel supplied JQ Functions

The camel-jq adds the following functions:

header - Allow to access the Message header in a JQ expression.

For example, to set the property foo with the value from the Message header `MyHeader':

from("direct:start")
    .transform()
        .jq(".foo = header(\"MyHeader\")")
    .to("mock:result");

Dependencies

If you use Maven you could just add the following to your pom.xml, substituting the version number for the latest and greatest release (see the download page for the latest versions).

<dependency>
  <groupId>org.apache.camel</groupId>
  <artifactId>camel-jq</artifactId>
  <version>x.x.x</version>
</dependency>