Route Template

A Route template is as its name implies a template for a route, which is used to create routes from a set of input parameters. In other words, route templates are parameterized routes.

Route template + input parameters ⇒ route

From a route template, you can create one or more routes.

Defining route templates in the DSL

Route templates are to be defined in the DSL (just like routes) as shown in the following:

Java
XML
YAML

public class MyRouteTemplates extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        // create a route template with the given name
        routeTemplate("myTemplate")
            // here we define the required input parameters (can have default values)
            .templateParameter("name")
            .templateParameter("greeting")
            .templateParameter("myPeriod", "3s")
            // here comes the route in the template
            // notice how we use {{name}} to refer to the template parameters
            // we can also use {{propertyName}} to refer to property placeholders
            .from("timer:{{name}}?period={{myPeriod}}")
                .setBody(simple("{{greeting}} ${body}"))
                .log("${body}");
    }
}

  <routeTemplate id="myTemplate">
    <templateParameter name="name"/>
    <templateParameter name="greeting"/>
    <templateParameter name="myPeriod" defaultValue="3s"/>
    <route>
      <from uri="timer:{{name}}?period={{myPeriod}}"/>
      <setBody><simple>{{greeting}} ${body}</simple></setBody>
      <log message="${body}"/>
    </route>
  </routeTemplate>

- routeTemplate:
    id: "myTemplate"
    parameters:
      - name: "name"
      - name: "greeting"
      - name: "myPeriod"
        defaultValue: "3s"
    from:
      uri: "timer:{{name}}?period={{myPeriod}}"
      steps:
        - setBody:
            expression:
              simple:
                expression: "{{greeting}} ${body}"
        - log:
            message: "${body}"

In the examples above, there was one route template, but you can define as many as you want. Each template must have a unique id.

Template parameters

The template parameters are used for defining the parameters the template accepts. In the example, there are three parameters: name, greeting, and myPeriod. The first two parameters are mandatory, whereas myPeriod is optional as it has a default value of 3s.

The template parameters are then used in the route as regular property placeholders with the {{ }} syntax. Notice how we use {{name}} and {{greeting}} in the timer endpoint and the simple language.

The route can use regular property placeholders from a properties file as well:

Application Properties

greeting = Davs

Then Camel would normally have used this value Davs when creating the route. However, as the route template has defined a template parameter with the same name greeting then a value must be provided when creating routes from the template.

Template parameters take precedence over regular property placeholders.

Special Property Placeholders

Template property placeholders are placed between two curly braces:

{{myProperty}}

To indicate that a template parameter is optional, and can have a null value, a question mark (?) must be used, as shown:

{{?myProperty}}

For example in the following route the replyTo queue for the JMS endpoint is optional. So if the value is null then Camel will not assign null as replyTo in the JMS endpoint, and instead leave it as if was never configured; for example this allows the option to use its default setting.

Java
XML
YAML

Notice how we use ? in the replyTo option below:

from("timer:{{name}}?period={{myPeriod}}")
    .setBody(simple("{{greeting}} ${body}"))
    .to("jms:myqueue?replyTo={{?replyToQueue}}");

Notice how we use ? in the replyTo option below:

<route>
    <from uri="timer:{{name}}?period={{myPeriod}}"/>
    <setBody>
        <simple>{{greeting}} ${body}</simple>
    </setBody>
    <to uri="jms:myqueue?replyTo={{?replyToQueue}}"/>
</route>

Notice how we use ? in the replyTo option below:

- route:
    from:
      uri: "timer:{{name}}?period={{myPeriod}}"
      steps:
        - setBody:
            expression:
              simple:
                expression: "{{greeting}} ${body}"
        - to:
            uri: "jms:myqueue?replyTo={{?replyToQueue}}"

In case no replyToQueue property is provided when creating the template the option replyTo is just ignored.

A property can also have a logical negation using the exclamation mark (!):

{{!myProperty}}

In the following example we have the parameter named disableTest which we then need to negate when configuring this on the JMS endpoint for its testConnectionOnStartup option. This means that disableTest=true resolves as testConnectionOnStartup=false, and visa-versa. To support this then we must use the negation using the ! mark:

Java
XML
YAML

from("timer:{{name}}?period={{myPeriod}}")
    .setBody(simple("{{greeting}} ${body}"))
    .to("jms:myqueue?replyTo={{?replyToQueue}}&testConnectionOnStartup={{!disableTest}}");

<route>
    <from uri="timer:{{name}}?period={{myPeriod}}"/>
    <setBody>
        <simple>{{greeting}} ${body}</simple>
    </setBody>
    <to uri="jms:myqueue?replyTo={{?replyToQueue}}&amp;testConnectionOnStartup={{!disableTest}}"/>
</route>

- route:
    from:
      uri: timer
      parameters:
        timerName: "{{name}}"
        period: "{{myPeriod}}"
      steps:
        - setBody:
            expression:
              simple:
                expression: "{{greeting}} ${body}"
        - to:
            uri: jms
            parameters:
              destinationName: myqueue
              replyTo: "{{?replyToQueue}}"
              testConnectionOnStartup: "{{!disableTest}}"

Creating a route from a route template

To create routes from route templates, then this is possible from standard Java code, and all the Camel DSLs.

In the following code snippet, we create 2 routes from the same template, but with different parameters.

Java
Java DSL
XML
YAML

Here we create routes from standard Java using the Camel Java API using org.apache.camel.builder.TemplatedRouteBuilder that uses a fluent builder style.

// create two routes from the template
TemplatedRouteBuilder.builder(context, "myTemplate")
    .parameter("name", "one")
    .parameter("greeting", "Hello")
    .add(); // adds a new route from the given input parameters

TemplatedRouteBuilder.builder(context, "myTemplate")
    .parameter("name", "two")
    .parameter("greeting", "Bonjour")
    .parameter("myPeriod", "5s")
    .add(); // adds a new route from the given input parameters

Here we create routes from inside a regular RouteBuilder using Java DSL where each templatedRoute will create and add a new route from the given input parameters.

templatedRoute("myTemplate")
        .parameter("name", "one")
        .parameter("greeting", "Hello");

templatedRoute("myTemplate")
        .parameter("name", "two")
        .parameter("greeting", "Bonjour")
        .parameter("myPeriod", "5s");

  <templatedRoute routeTemplateRef="myTemplate">
    <parameter name="name" value="one"/>
    <parameter name="greeting" value="Hello"/>
  </templatedRoute>

  <templatedRoute routeTemplateRef="myTemplate">
    <parameter name="name" value="two"/>
    <parameter name="greeting" value="Bonjour"/>
    <parameter name="myPeriod" value="5s"/>
  </templatedRoute>

- templatedRoute:
    routeTemplateRef: "myTemplate"
    parameters:
      - name: "name"
        value: "one"
      - name: "greeting"
        value: "Hello"

- templatedRoute:
    routeTemplateRef: "myTemplate"
    parameters:
      - name: "name"
        value: "two"
      - name: "greeting"
        value: "Bonjour"
      - name: "myPeriod"
        value: "5s"

In Java code then the returned value from add method is the route id of the new route that was added. However null is returned if the route is not yet created and added, which can happen if CamelContext is not started yet.

If no route id is provided, then Camel will auto assign a route id. In the example above then Camel would assign route ids such as route1, route2 to these routes.

If you want to specify a route id, then use routeId as follows, where the id is set to myCoolRoute:

Java
Java DSL
XML
YAML

TemplatedRouteBuilder.builder(context, "myTemplate")
    .routeId("myCoolRoute")
    .parameter("name", "one")
    .parameter("greeting", "hello")
    .parameter("myPeriod", "5s")
    .add();

templatedRoute("myTemplate")
        .routeId("myCoolRoute")
        .parameter("name", "one")
        .parameter("greeting", "hello")
        .parameter("myPeriod", "5s");

  <templatedRoute routeTemplateRef="myTemplate" routeId="myCoolRoute">
    <parameter name="name" value="one"/>
    <parameter name="greeting" value="hello"/>
    <parameter name="myPeriod" value="5s"/>
  </templatedRoute>

- templatedRoute:
    routeTemplateRef: "myTemplate"
    routeId: "myCoolRoute"
    parameters:
      - name: "name"
        value: "one"
      - name: "greeting"
        value: "hello"
      - name: "myPeriod"
        value: "5s"

Using template parameters with Java DSL Simple builder

When using Java DSL and Simple language, then beware that you should not use the simple fluent builder when defining the simple expressions/predicates.

For example, given the following route template in Java DSL:

public class MyRouteTemplates extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        routeTemplate("myTemplate")
            .templateParameter("name")
            .templateParameter("color")
            .from("direct:{{name}}")
                .choice()
                    .when(simple("{{color}}").isEqualTo("red")) (1)
                        .to("direct:red")
                    .otherwise()
                        .to("color:other")
                .end();
    }
}

1	This is not supported (see explanation below)

Then notice how the simple predicate is using simple fluent builder simple("{{color}}").isEqualTo("red"). This is not supported with route templates and would not work when creating multiple routes from the template.

Instead, the simple expression should be a literal String value only as follows:

.when(simple("'{{color}}' == 'red'")

So the correct solution would be as follows:

public class MyRouteTemplates extends RouteBuilder {

    @Override
    public void configure() throws Exception {
        routeTemplate("myTemplate")
            .templateParameter("name")
            .templateParameter("color")
            .from("direct:{{name}}")
                .choice()
                    .when(simple("'{{color}}' == 'red'") (1)
                        .to("direct:red")
                    .otherwise()
                        .to("color:other")
                .end();
    }
}

1	This is supported and the simple expression as a String literal can be used as-is in all the Camel DSL.

Using hardcoded node IDs in route templates

If route templates contain hardcoded node IDs, then routes created from templates will use the same IDs. Therefore, if two or more routes are created from the same template, you will have duplicate id detected error.

Given the route template below, then it has hardcoded ID (new-order) in node calling the http services.

Java
XML
YAML

routeTemplate("orderTemplate")
    .templateParameter("queue")
    .from("jms:{{queue}}")
        .to("http:orderserver.acme.com/neworder").id("new-order") (1)
        .log("Processing order");

1	Hardcoded ID on the To EIP

<routeTemplate id="orderTemplate">
    <templateParameter name="queue"/>
    <route>
        <from uri="jms:{{queue}}"/>
        <to id="new-order" uri="http:orderserver.acme.com/neworder"/> (1)
        <log message="Processing order"/>
    </route>
</routeTemplate>

1	Hardcoded ID on the To EIP

- routeTemplate:
    id: "myTemplate"
    parameters:
      - name: "queue"
    from:
      uri: "jms:{{queue}}"
      steps:
        - to:
            id: new-order (1)
            uri: http:orderserver.acme.com/neworder
        - log:
            message: Processing order

1	Hardcoded ID on the To EIP

When creating routes from templates, you can then provide a prefix which is used for all node IDs. This allows to create 2 or more routes without duplicate id errors.

For example in the following, we create a new route myCoolRoute from the myTemplate template, and use a prefix of web.

Java
XML
YAML

templatedRoute("orderTemplate")
        .routeId("webOrder")
        .prefixId("web")
        .parameter("queue", "order.web");

Then we can create a 2nd route with a different _prefixId`:

templatedRoute("orderTemplate")
        .routeId("ftpOrder")
        .prefixId("ftp")
        .parameter("queue", "order.ftp");

  <templatedRoute routeTemplateRef="orderTemplate" routeId="webOrder" prefixId="web">
    <parameter name="queue" value="web"/>
  </templatedRoute>

Then we can create a 2nd route with a different _prefixId`:

  <templatedRoute routeTemplateRef="orderTemplate" routeId="ftpOrder" prefixId="ftp">
    <parameter name="queue" value="order.ftp"/>
  </templatedRoute>

- templatedRoute:
    routeTemplateRef: "orderTemplate"
    routeId: "webOrder"
    prefixId: "web"
    parameters:
      - name: "queue"
        value: "web"

Then we can create a 2nd route with a different _prefixId`:

- templatedRoute:
    routeTemplateRef: "orderTemplate"
    routeId: "ftpOrder"
    prefixId: "ftp"
    parameters:
      - name: "queue"
        value: "order.ftp"

Binding beans to route template (advanced)

The route template allows binding beans that are locally scoped and only used as part of creating routes from the template. This allows using the same template to create multiple routes, where beans are local (private) for each created route.

For example, given the following route template where we use templateBean to set up the local bean as shown:

routeTemplate("s3template")
    .templateParameter("region")
    .templateParameter("bucket")
    .templateBean("myClient", S3Client.class, rtc ->
            S3Client.builder().region(rtc.getProperty("region", Region.class)).build();
    )
    .from("direct:s3-store")
     // must refer to the bean with {{myClient}}
    .to("aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}")

The template has two parameters to specify the AWS region and the S3 bucket. To connect to S3 then a software.amazon.awssdk.services.s3.S3Client bean is necessary.

To create this bean, we specify this with the templateBean DSL where we specify the bean id as myClient. The type of the bean can be specified (S3Client.class), however, it is optional, and can be used if you need to let beans be discovered by type and not by name.

This ensures that the code creating the bean is executed later (when Camel is creating a route from the template), then the code must be specified as a supplier. Because we want during creation of the bean access to template parameters, we use a Camel BeanSupplier which gives access to RouteTemplateContext that is the rtc variable in the code above.

The local bean with id myClient must be referred to using Camel’s property placeholder syntax, eg {{myClient}} in the route template, as shown above with the to endpoint. This is because the local bean must be made unique and Camel will internally re-assign the bean id to use a unique id instead of myClient. And this is done with the help of the property placeholder functionality.

If multiple routes are created from this template, then each of the created routes have their own S3Client bean created.

Binding beans to route templates from template builder

The TemplatedRouteBuilder also allows to bind local beans (which allows specifying those beans) when creating routes from existing templates.

Suppose the route template below is defined in XML:

  <routeTemplate id="s3template">
    <templateParameter name="region"/>
    <templateParameter name="bucket"/>
    <route>
      <from uri="direct:s3-store"/>
      <to uri="aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"/>
    </route>
  </routeTemplate>

The template has no bean bindings for #{{myClient}} which would be required for creating the template.

When creating routes form the template via TemplatedRouteBuilder then you can provide the bean binding if you desire the bean to be locally scoped (not shared with others):

Java
Java DSL
XML
YAML

TemplatedRouteBuilder.builder(context, "s3template")
    .parameter("region", "US-EAST-1")
    .parameter("bucket", "myBucket")
    .bean("myClient", S3Client.class,
                S3Client.builder()
                    .region(rtc.getProperty("region", Region.class))
                    .build())
    .routeId("mys3route")
    .add();

As you can see the binding is similar to when using templateBean directly in the route template.

templatedRoute("s3template")
        .parameter("region", "US-EAST-1")
        .parameter("bucket", "myBucket")
        .bean("myClient", S3Client.class,
                rtc -> S3Client.builder() (1)
                    .region(rtc.getProperty("region", Region.class))
                    .build())
        .routeId("mys3route");

1	Note that the third parameter of the `bean` method is not directly the bean but rather a factory method that will be used to create the bean, here we use a lambda expression as factory method.

  <templatedRoute routeTemplateRef="s3template" routeId="mys3route">
    <parameter name="region" value="US-EAST-1"/>
    <parameter name="bucket" value="myBucket"/>
    <bean name="myClient" type="software.amazon.awssdk.services.s3.S3Client"
          scriptLanguage="groovy"> (1)
        <script>
            import software.amazon.awssdk.services.s3.S3Client
            S3Client.builder()
                .region(rtc.getProperty("region", Region.class))
                .build()
        </script>
    </bean>
  </templatedRoute>

1	For non-Java DSL, in case of a complex bean factory, you can still rely on a language like `groovy` to define your bean factory inside a `script` element.

- templatedRoute:
    routeTemplateRef: "s3template"
    routeId: "mys3route"
    parameters:
      - name: "region"
        value: "US-EAST-1"
      - name: "bucket"
        value: "myBucket"
    beans:
      - name: "myClient"
        type: "software.amazon.awssdk.services.s3.S3Client"
        scriptLanguage: "groovy"
        script: | (1)
            import software.amazon.awssdk.services.s3.S3Client
            S3Client.builder()
                .region(rtc.getProperty("region", Region.class))
                .build()

1	For non-Java DSL, in case of a complex bean factory, you can still rely on a language like `groovy` to define your bean factory as value of the `script` key.

Instead of binding the beans from the template builder, you could also create the bean outside the template, and bind it by reference.

Java
Java DSL

final S3Client myClient = S3Client.builder().region(Region.US_EAST_1).build();

TemplatedRouteBuilder.builder(context, "s3template")
    .parameter("region", Region.US_EAST_1)
    .parameter("bucket", "myBucket")
    .bean("myClient", myClient)
    .routeId("mys3route")
    .add();

final S3Client myClient = S3Client.builder().region(Region.US_EAST_1).build();

templatedRoute("s3template")
        .parameter("region", "US-EAST-1")
        .parameter("bucket", "myBucket")
        .bean("myClient", S3Client.class, rtc -> myClient)
        .routeId("mys3route");

You should prefer to create the local beans directly from within the template (if possible) because this ensures the route template has this out of the box. Otherwise, the bean must be created or provided every time a new route is created from the route template. However, the latter gives freedom to create the bean in any other custom way.

Binding beans to route templates using bean types

You can create a local bean by referring to a fully qualified class name which Camel will use to create a new local bean instance. When using this, the created bean is created via default constructor of the class.

The bean instance can be configured with properties via getter/setter style. The previous example with creating the AWS S3Client would not support this kind as this uses fluent builder pattern (not getter/setter).

In Camel 4.6 onwards, you can also use constructor arguments for beans

So suppose we have a class as follows:

public class MyBar {
    private String name;
    private String address;

    // getter/setter omitted

    public String location() {
        return "The bar " + name + " is located at " + address;
    }
}

Then we can use the MyBar class as a local bean in a route template as follows:

Java
XML
YAML

routeTemplate("barTemplate")
    .templateParameter("bar")
    .templateParameter("street")
    .templateBean("myBar")
        .typeClass("com.foo.MyBar")
        .property("name", "{{bar}}")
        .property("address", "{{street}}")
    .end()
    .from("direct:going-out")
        .to("bean:{{myBar}}");

With Java DSL, you can also refer to the bean class using type safe way in typeClass by referring to the .class as follows:

routeTemplate("barTemplate")
    .templateParameter("bar")
    .templateParameter("street")
    .templateBean("myBar")
        .typeClass(MyBar.class)
        .property("name", "{{bar}}")
        .property("address", "{{street}}")
    .end()
    .from("direct:going-out")
        .to("bean:{{myBar}}");

In XML, we specify the class FQN name using #class: syntax as shown:

<routeTemplate id="myBar">
    <templateParameter name="bar"/>
    <templateParameter name="street"/>
    <templateBean name="myBean" type="#class:com.foo.MyBar">
        <properties>
            <property key="name" value="{{bar}}"/>
            <property key="address" value="{{street}}"/>
        </properties>
    </templateBean>
    <route>
        <from uri="direct:going-out"/>
        <to uri="bean:{{myBar}}"/>
    </route>
</routeTemplate>

In YAML, we specify the class FQN name using #class: syntax as shown:

- routeTemplate:
    id: "myBar"
    parameters:
      - name: "bar"
      - name: "street"
    beans:
      - name: "myBean"
        type: "#class:com.foo.MyBar"
        properties:
          name: "{{bar}}"
          address: "{{street}}"
    from:
      uri: direct:going-out
      steps:
        - to:
            uri: "bean:{{myBar}}"

Binding beans to route templates using scripting languages (advanced)

You can use scripting languages like Groovy, Java, to create the bean. This allows defining route templates with the scripting language supported by Camel such as Groovy.

For example, creating the AWS S3 client can be done as shown in Java (with inlined Groovy code):

Java
XML
YAML

routeTemplate("s3template")
    .templateParameter("region")
    .templateParameter("bucket")
    .templateBean("myClient", "groovy",
            "software.amazon.awssdk.services.s3.S3Client.S3Client.builder()
            .region(rtc.getProperty("region", Region.class))
            .build()"
    )
    .from("direct:s3-store")
     // must refer to the bean with {{myClient}}
    .to("aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}")

Notice how the Groovy code can be inlined directly in the route template in XML also.

  <routeTemplate id="s3template">
    <templateParameter name="region"/>
    <templateParameter name="bucket"/>
    <templateBean name="myClient" scriptLanguage="groovy">
        <script>
            import software.amazon.awssdk.services.s3.S3Client
            S3Client.builder()
                .region(rtc.getProperty("region", Region.class))
                .build()
        </script>
    </templateBean>
    <route>
      <from uri="direct:s3-store"/>
      <to uri="aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"/>
    </route>
  </routeTemplate>

Notice how the Groovy code can be inlined directly in the route template in DSL also.

- routeTemplate:
    id: "s3template"
    parameters:
      - name: "region"
      - name: "bucket"
    beans:
      - name: "myClient"
        scriptLanguage: "groovy"
        script: |
            import software.amazon.awssdk.services.s3.S3Client
            S3Client.builder()
                .region(rtc.getProperty("region", Region.class))
                .build()
    from:
      uri: direct:s3-store
      steps:
        - to:
            uri: "aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"

The groovy code can be externalized into a file on the classpath or file system, by using resource: as prefix, such as:

Java
XML
YAML

routeTemplate("s3template")
    .templateParameter("region")
    .templateParameter("bucket")
    .templateBean("myClient", "groovy", "resource:classpath:s3bean.groovy")
    .from("direct:s3-store")
     // must refer to the bean with {{myClient}}
    .to("aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}")

Notice how we can tell Camel the type of the bean is software.amazon.awssdk.services.s3.S3Client which allows Camel to better understand, and also makes the bean able for autowiring and binding via type. The type is optional and can be omitted. For example in this example as we inject the bean via its bean id myClient.

  <routeTemplate id="s3template">
    <templateParameter name="region"/>
    <templateParameter name="bucket"/>
    <templateBean name="myClient" scriptLanguage="groovy"
                  type="software.amazon.awssdk.services.s3.S3Client">
        <script>resource:classpath:s3bean.groovy</script>
    </templateBean>
    <route>
      <from uri="direct:s3-store"/>
      <to uri="aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"/>
    </route>
  </routeTemplate>

- routeTemplate:
    id: "s3template"
    parameters:
      - name: "region"
      - name: "bucket"
    beans:
      - name: "myClient"
        scriptLanguage: "groovy"
        type: "software.amazon.awssdk.services.s3.S3Client"
        script: "resource:classpath:s3bean.groovy"
    from:
      uri: direct:s3-store
      steps:
        - to:
            uri: "aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"

Then create the file s3bean.groovy in the classpath root:

s3bean.groovy

import software.amazon.awssdk.services.s3.S3Client

S3Client.builder()
    .region(rtc.getProperty("region", Region.class))
    .build()

The languages supported you can specify as scriptLanguage are:

Type Description

Type	Description
bean	Calling a method on a Java class to create the bean.
groovy	Using a groovy script to create the bean.
java	Java code which is runtime compiled (using jOOR library) to create the bean.
mvel	To use a MVEL template script to create the bean.
ognl	To use OGNL template script to create the bean.
*name*	To use a third-party language by the given `name` to create the bean.

bean

Calling a method on a Java class to create the bean.

groovy

Using a groovy script to create the bean.

java

Java code which is runtime compiled (using jOOR library) to create the bean.

mvel

To use a MVEL template script to create the bean.

ognl

To use OGNL template script to create the bean.

name

To use a third-party language by the given name to create the bean.

Camel will bind RouteTemplateContext as the root object with name rtc when evaluating the script. This means you can get access to all the information from RouteTemplateContext and CamelContext via rtc.

This is what we have done in the scripts in the previous examples where we get hold of a template parameter with:

rtc.getProperty('region', String.class)

To get access to CamelContext you can do:

var cn = rtc.getCamelContext().getName()

The most powerful languages to use are groovy and java. The other languages are limited in flexibility as they are not complete programming languages, but are more suited for templating needs.

It is recommended to either use groovy or java, if creating the local bean requires coding, and the route templates are not defined using Java code.

The bean language can be used when creating the local bean from an existing Java method (static or not-static method), and the route templates are not defined using Java code.

For example suppose there is a class named com.foo.MyAwsHelper that has a method called createS3Client then you can call this method from the route template as shown in the following:

Java
XML
YAML

routeTemplate("s3template")
    .templateParameter("region")
    .templateParameter("bucket")
    .templateBean("myClient", "beam", "com.foo.MyAwsHelper?method=createS3Client")
    .from("direct:s3-store")
     // must refer to the bean with {{myClient}}
    .to("aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}")

  <routeTemplate id="s3template">
    <templateParameter name="region"/>
    <templateParameter name="bucket"/>
    <templateBean name="myClient" type="bean">
        <script>com.foo.MyAwsHelper?method=createS3Client</script>
    </templateBean>
    <route>
      <from uri="direct:s3-store"/>
      <to uri="aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"/>
    </route>
  </routeTemplate>

- routeTemplate:
    id: "s3template"
    parameters:
      - name: "region"
      - name: "bucket"
    beans:
      - name: "myClient"
        scriptLanguage: "bean"
        script: "com.foo.MyAwsHelper?method=createS3Client"
    from:
      uri: direct:s3-store
      steps:
        - to:
            uri: "aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"

The method signature of createS3Client method MUST then have one parameter for the RouteTemplateContext as shown:

public static S3Client createS3Client(RouteTemplateContext rtc) {
    return S3Client.builder()
        .region(rtc.getProperty("region", Region.class))
        .build();
}

If you are using pure Java code (both template and creating local bean), then you can create the local bean using Java lambda style as previously documented.

Configuring the type of the created bean

The type must be set to define what FQN class the created bean.

In the following route template we want to tell Camel that the bean is a software.amazon.awssdk.services.s3.S3Client type.

Java
XML
YAML

In Java DSL you can refer to the type via its class (ie S3Client.java which is a type safe way:

routeTemplate("s3template")
    .templateParameter("region")
    .templateParameter("bucket")
    .templateBean("myClient", S3Client.class, "bean", "com.foo.MyAwsHelper?method=createS3Client")
    .from("direct:s3-store")
     // must refer to the bean with {{myClient}}
    .to("aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}")

  <routeTemplate id="s3template">
    <templateParameter name="region"/>
    <templateParameter name="bucket"/>
    <templateBean name="myClient" scriptLanguage="bean"
                  type="software.amazon.awssdk.services.s3.S3Client">
        <script>com.foo.MyAwsHelper?method=createS3Client</script>
    </templateBean>
    <route>
      <from uri="direct:s3-store"/>
      <to uri="aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"/>
    </route>
  </routeTemplate>

- routeTemplate:
    id: "s3template"
    parameters:
      - name: "region"
      - name: "bucket"
    beans:
      - name: "myClient"
        scriptLanguage: "bean"
        type: "software.amazon.awssdk.services.s3.S3Client"
        script: "com.foo.MyAwsHelper?method=createS3Client"
    from:
      uri: direct:s3-store
      steps:
        - to:
            uri: "aws2-s3:{{bucket}}?amazonS3Client=#{{myClient}}"

Configuring route templates when creating route (advanced)

There may be some special situations where you want to be able to do some custom configuration/code when a route is about to be created from a route template.

This is only available in Java DSL

To support this you can use the configure in the route template DSL where you can specify the code to execute as show:

routeTemplate("myTemplate")
    .templateParameter("myTopic")
    .configure((RouteTemplateContext rtc) ->
        // do some custom code here
    )
    .from("direct:to-topic")
    .to("kafka:{{myTopic}}");

JMX management

The route templates can be dumped as XML from the ManagedCamelContextMBean MBean via the dumpRouteTemplatesAsXml operation.

Creating routes from a properties file

When using camel-main you can specify the parameters for route templates in application.properties file.

For example, given the route template below (from a RouteBuilder class):

routeTemplate("mytemplate")
    .templateParameter("input")
    .templateParameter("result")
    .from("direct:{{input}}")
        .to("mock:{{result}}");

Then we can create two routes from this template by configuring the values in the application.properties file:

camel.route-template[0].template-id=mytemplate
camel.route-template[0].input=foo
camel.route-template[0].result=cheese

camel.route-template[1].template-id=mytemplate
camel.route-template[1].input=bar
camel.route-template[1].result=cheese

Creating routes from custom sources of template parameters

The SPI interface org.apache.camel.spi.RouteTemplateParameterSource can be used to implement custom sources that are used during startup of Camel to create routes via the templates with parameters from the custom source(s).

For example, a custom source can be implemented to read parameters from a shared database that Camel uses during startup to create routes. This allows externalizing these parameters and as well to easily add more routes with varying parameters.

To let Camel discover custom sources, then register the source into the Camel registry.

Route Template

Defining route templates in the DSL

Template parameters

Special Property Placeholders

Creating a route from a route template

Using template parameters with Java DSL Simple builder

Using hardcoded node IDs in route templates

Binding beans to route template (advanced)

Binding beans to route templates from template builder

Binding beans to route templates using bean types

Binding beans to route templates using scripting languages (advanced)

Configuring the type of the created bean

Configuring route templates when creating route (advanced)

JMX management

Creating routes from a properties file

Creating routes from custom sources of template parameters

See Also