Stub :: Apache Camel

URI format

stub:someUri

Where someUri can be any URI with any query parameters.

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 Stub component supports 12 options, which are listed below.

Name	Description	Default	Type
shadow (common)	If shadow is enabled then the stub component will register a shadow endpoint with the actual uri that refers to the stub endpoint, meaning you can lookup the endpoint via both stub:kafka:cheese and kafka:cheese.	false	boolean
shadowPattern (common)	If shadow is enabled then this pattern can be used to filter which components to match. Multiple patterns can be separated by comma.		String
bridgeErrorHandler (consumer)	Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.	false	boolean
concurrentConsumers (consumer)	Sets the default number of concurrent threads processing exchanges.	1	int
defaultPollTimeout (consumer (advanced))	The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.	1000	int
defaultBlockWhenFull (producer)	Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.	false	boolean
defaultDiscardWhenFull (producer)	Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.	false	boolean
defaultOfferTimeout (producer)	Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, where a configured timeout can be added to the block case. Using the .offer(timeout) method of the underlining java queue.		long
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
autowiredEnabled (advanced)	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
defaultQueueFactory (advanced)	Sets the default queue factory.		BlockingQueueFactory
queueSize (advanced)	Sets the default maximum capacity of the SEDA queue (i.e., the number of messages it can hold).	1000	int

Name

Description

Default

Type

shadow (common)

If shadow is enabled then the stub component will register a shadow endpoint with the actual uri that refers to the stub endpoint, meaning you can lookup the endpoint via both stub:kafka:cheese and kafka:cheese.

false

boolean

shadowPattern (common)

If shadow is enabled then this pattern can be used to filter which components to match. Multiple patterns can be separated by comma.

String

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

concurrentConsumers (consumer)

Sets the default number of concurrent threads processing exchanges.

1

int

defaultPollTimeout (consumer (advanced))

The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.

1000

int

defaultBlockWhenFull (producer)

Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.

false

boolean

defaultDiscardWhenFull (producer)

Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.

false

boolean

defaultOfferTimeout (producer)

Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, where a configured timeout can be added to the block case. Using the .offer(timeout) method of the underlining java queue.

long

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

autowiredEnabled (advanced)

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

defaultQueueFactory (advanced)

Sets the default queue factory.

BlockingQueueFactory

queueSize (advanced)

Sets the default maximum capacity of the SEDA queue (i.e., the number of messages it can hold).

1000

int

Endpoint Options

The Stub endpoint is configured using URI syntax:

stub:name

With the following path and query parameters:

Path Parameters (1 parameters)

Name	Description	Default	Type
name (common)	Required Name of queue.		String

Name

Description

Default

Type

name (common)

Required Name of queue.

String

Query Parameters (18 parameters)

Name	Description	Default	Type
size (common)	The maximum capacity of the SEDA queue (i.e., the number of messages it can hold). Will by default use the defaultSize set on the SEDA component.	1000	int
concurrentConsumers (consumer)	Number of concurrent threads processing exchanges.	1	int
bridgeErrorHandler (consumer (advanced))	Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.	false	boolean
exceptionHandler (consumer (advanced))	To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.		ExceptionHandler
exchangePattern (consumer (advanced))	Sets the exchange pattern when the consumer creates an exchange. Enum values: InOnly InOut		ExchangePattern
limitConcurrentConsumers (consumer (advanced))	Whether to limit the number of concurrentConsumers to the maximum of 500. By default, an exception will be thrown if an endpoint is configured with a greater number. You can disable that check by turning this option off.	true	boolean
multipleConsumers (consumer (advanced))	Specifies whether multiple consumers are allowed. If enabled, you can use SEDA for Publish-Subscribe messaging. That is, you can send a message to the SEDA queue and have each consumer receive a copy of the message. When enabled, this option should be specified on every consumer endpoint.	false	boolean
pollTimeout (consumer (advanced))	The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.	1000	int
purgeWhenStopping (consumer (advanced))	Whether to purge the task queue when stopping the consumer/route. This allows to stop faster, as any pending messages on the queue is discarded.	false	boolean
blockWhenFull (producer)	Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.	false	boolean
discardIfNoConsumers (producer)	Whether the producer should discard the message (do not add the message to the queue), when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.	false	boolean
discardWhenFull (producer)	Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.	false	boolean
failIfNoConsumers (producer)	Whether the producer should fail by throwing an exception, when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.	false	boolean
offerTimeout (producer)	Offer timeout (in milliseconds) can be added to the block case when queue is full. You can disable timeout by using 0 or a negative value.		long
timeout (producer)	Timeout (in milliseconds) before a SEDA producer will stop waiting for an asynchronous task to complete. You can disable timeout by using 0 or a negative value.	30000	long
waitForTaskToComplete (producer)	Option to specify whether the caller should wait for the async task to complete or not before continuing. The following three options are supported: Always, Never or IfReplyExpected. The first two values are self-explanatory. The last value, IfReplyExpected, will only wait if the message is Request Reply based. The default option is IfReplyExpected. Enum values: Never IfReplyExpected Always	IfReplyExpected	WaitForTaskToComplete
lazyStartProducer (producer (advanced))	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
queue (advanced)	Define the queue instance which will be used by the endpoint.		BlockingQueue

Name

Description

Default

Type

size (common)

The maximum capacity of the SEDA queue (i.e., the number of messages it can hold). Will by default use the defaultSize set on the SEDA component.

1000

int

concurrentConsumers (consumer)

Number of concurrent threads processing exchanges.

1

int

bridgeErrorHandler (consumer (advanced))

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

boolean

exceptionHandler (consumer (advanced))

To let the consumer use a custom ExceptionHandler. Notice if the option bridgeErrorHandler is enabled then this option is not in use. By default the consumer will deal with exceptions, that will be logged at WARN or ERROR level and ignored.

ExceptionHandler

exchangePattern (consumer (advanced))

Sets the exchange pattern when the consumer creates an exchange.

Enum values:

InOnly
InOut

ExchangePattern

limitConcurrentConsumers (consumer (advanced))

Whether to limit the number of concurrentConsumers to the maximum of 500. By default, an exception will be thrown if an endpoint is configured with a greater number. You can disable that check by turning this option off.

true

boolean

multipleConsumers (consumer (advanced))

Specifies whether multiple consumers are allowed. If enabled, you can use SEDA for Publish-Subscribe messaging. That is, you can send a message to the SEDA queue and have each consumer receive a copy of the message. When enabled, this option should be specified on every consumer endpoint.

false

boolean

pollTimeout (consumer (advanced))

The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.

1000

int

purgeWhenStopping (consumer (advanced))

Whether to purge the task queue when stopping the consumer/route. This allows to stop faster, as any pending messages on the queue is discarded.

false

boolean

blockWhenFull (producer)

Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.

false

boolean

discardIfNoConsumers (producer)

Whether the producer should discard the message (do not add the message to the queue), when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.

false

boolean

discardWhenFull (producer)

Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.

false

boolean

failIfNoConsumers (producer)

Whether the producer should fail by throwing an exception, when sending to a queue with no active consumers. Only one of the options discardIfNoConsumers and failIfNoConsumers can be enabled at the same time.

false

boolean

offerTimeout (producer)

Offer timeout (in milliseconds) can be added to the block case when queue is full. You can disable timeout by using 0 or a negative value.

long

timeout (producer)

Timeout (in milliseconds) before a SEDA producer will stop waiting for an asynchronous task to complete. You can disable timeout by using 0 or a negative value.

30000

long

waitForTaskToComplete (producer)

Option to specify whether the caller should wait for the async task to complete or not before continuing. The following three options are supported: Always, Never or IfReplyExpected. The first two values are self-explanatory. The last value, IfReplyExpected, will only wait if the message is Request Reply based. The default option is IfReplyExpected.

Enum values:

Never
IfReplyExpected
Always

IfReplyExpected

WaitForTaskToComplete

lazyStartProducer (producer (advanced))

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

queue (advanced)

Define the queue instance which will be used by the endpoint.

BlockingQueue

Usage

Internally, the Stub component creates Seda endpoints. The main difference between Stub and Seda is that Seda will validate the URI and parameters you give it, so putting seda: in front of a typical URI with query arguments will usually fail. Stub won’t, though, as it basically ignores all query parameters to let you quickly stub out one or more endpoints in your route temporarily.

Examples

Here are a few samples of stubbing endpoint uris

stub:smtp://somehost.foo.com?user=whatnot&something=else
stub:http://somehost.bar.com/something

Spring Boot Auto-Configuration

When using stub 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-stub-starter</artifactId>
  <version>x.x.x</version>
  <!-- use the same version as your Camel core version -->
</dependency>

The component supports 13 options, which are listed below.

Name	Description	Default	Type
camel.component.stub.autowired-enabled	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
camel.component.stub.bridge-error-handler	Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.	false	Boolean
camel.component.stub.concurrent-consumers	Sets the default number of concurrent threads processing exchanges.	1	Integer
camel.component.stub.default-block-when-full	Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.	false	Boolean
camel.component.stub.default-discard-when-full	Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.	false	Boolean
camel.component.stub.default-offer-timeout	Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, where a configured timeout can be added to the block case. Using the .offer(timeout) method of the underlining java queue.		Long
camel.component.stub.default-poll-timeout	The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.	1000	Integer
camel.component.stub.default-queue-factory	Sets the default queue factory. The option is a org.apache.camel.component.seda.BlockingQueueFactory<org.apache.camel.Exchange> type.		BlockingQueueFactory
camel.component.stub.enabled	Whether to enable auto configuration of the stub component. This is enabled by default.		Boolean
camel.component.stub.lazy-start-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
camel.component.stub.queue-size	Sets the default maximum capacity of the SEDA queue (i.e., the number of messages it can hold).	1000	Integer
camel.component.stub.shadow	If shadow is enabled then the stub component will register a shadow endpoint with the actual uri that refers to the stub endpoint, meaning you can lookup the endpoint via both stub:kafka:cheese and kafka:cheese.	false	Boolean
camel.component.stub.shadow-pattern	If shadow is enabled then this pattern can be used to filter which components to match. Multiple patterns can be separated by comma.		String

Name

Description

Default

Type

camel.component.stub.autowired-enabled

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

camel.component.stub.bridge-error-handler

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions (if possible) occurred while the Camel consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. Important: This is only possible if the 3rd party component allows Camel to be alerted if an exception was thrown. Some components handle this internally only, and therefore bridgeErrorHandler is not possible. In other situations we may improve the Camel component to hook into the 3rd party component and make this possible for future releases. By default the consumer will use the org.apache.camel.spi.ExceptionHandler to deal with exceptions, that will be logged at WARN or ERROR level and ignored.

false

Boolean

camel.component.stub.concurrent-consumers

Sets the default number of concurrent threads processing exchanges.

1

Integer

camel.component.stub.default-block-when-full

Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will instead block and wait until the message can be accepted.

false

Boolean

camel.component.stub.default-discard-when-full

Whether a thread that sends messages to a full SEDA queue will be discarded. By default, an exception will be thrown stating that the queue is full. By enabling this option, the calling thread will give up sending and continue, meaning that the message was not sent to the SEDA queue.

false

Boolean

camel.component.stub.default-offer-timeout

Whether a thread that sends messages to a full SEDA queue will block until the queue’s capacity is no longer exhausted. By default, an exception will be thrown stating that the queue is full. By enabling this option, where a configured timeout can be added to the block case. Using the .offer(timeout) method of the underlining java queue.

Long

camel.component.stub.default-poll-timeout

The timeout (in milliseconds) used when polling. When a timeout occurs, the consumer can check whether it is allowed to continue running. Setting a lower value allows the consumer to react more quickly upon shutdown.

1000

Integer

camel.component.stub.default-queue-factory

Sets the default queue factory. The option is a org.apache.camel.component.seda.BlockingQueueFactory<org.apache.camel.Exchange> type.

BlockingQueueFactory

camel.component.stub.enabled

Whether to enable auto configuration of the stub component. This is enabled by default.

Boolean

camel.component.stub.lazy-start-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

camel.component.stub.queue-size

Sets the default maximum capacity of the SEDA queue (i.e., the number of messages it can hold).

1000

Integer

camel.component.stub.shadow

If shadow is enabled then the stub component will register a shadow endpoint with the actual uri that refers to the stub endpoint, meaning you can lookup the endpoint via both stub:kafka:cheese and kafka:cheese.

false

Boolean

camel.component.stub.shadow-pattern

If shadow is enabled then this pattern can be used to filter which components to match. Multiple patterns can be separated by comma.

String