Caffeine LoadCache

Since Camel 2.20

Only producer is supported

The Caffeine LoadCache component enables you to perform caching operations using the LoadingCache from Caffeine.

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

<dependency>
    <groupId>org.apache.camel</groupId>
    <artifactId>camel-caffeine</artifactId>
    <version>x.x.x</version>
    <!-- use the same version as your Camel core version -->
</dependency>

URI format

caffeine-loadcache://cacheName[?options]

You can append query options to the URI in the following format: ?option=value&option=#beanRef&…​

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 Caffeine LoadCache component supports 16 options, which are listed below.

Name Description Default Type

action (producer)

To configure the default cache action. If an action is set in the message header, then the operation from the header takes precedence.

Enum values:

  • GET

  • GET_ALL

  • PUT

  • PUT_ALL

  • INVALIDATE

  • INVALIDATE_ALL

  • CLEANUP

  • AS_MAP

String

createCacheIfNotExist (producer)

Automatic create the Caffeine cache if none has been configured or exists in the registry.

true

boolean

evictionType (producer)

Set the eviction Type for this cache.

Enum values:

  • size_based

  • time_based

SIZE_BASED

EvictionType

expireAfterAccessTime (producer)

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, the most recent replacement of its value, or its last read. Access time is reset by all cache read and write operations. The unit is in seconds.

300

int

expireAfterWriteTime (producer)

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, or the most recent replacement of its value. The unit is in seconds.

300

int

initialCapacity (producer)

Sets the minimum total size for the internal data structures. Providing a large enough estimate at construction time avoids the need for expensive resizing operations later, but setting this value unnecessarily high wastes memory.

Integer

key (producer)

To configure the default action key. If a key is set in the message header, then the key from the header takes precedence.

String

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

maximumSize (producer)

Specifies the maximum number of entries the cache may contain. Note that the cache may evict an entry before this limit is exceeded or temporarily exceed the threshold while evicting. As the cache size grows close to the maximum, the cache evicts entries that are less likely to be used again. For example, the cache may evict an entry because it hasn’t been used recently or very often. When size is zero, elements will be evicted immediately after being loaded into the cache. This can be useful in testing or to disable caching temporarily without a code change. As eviction is scheduled on the configured executor, tests may instead prefer to configure the cache to execute tasks directly on the same thread.

Integer

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

cacheLoader (advanced)

To configure a CacheLoader in case of a LoadCache use.

CacheLoader

configuration (advanced)

Sets the global component configuration.

CaffeineConfiguration

removalListener (advanced)

Set a specific removal Listener for the cache.

RemovalListener

statsCounter (advanced)

Set a specific Stats Counter for the cache stats.

StatsCounter

statsEnabled (advanced)

To enable stats on the cache.

false

boolean

valueType (advanced)

The cache value type, default java.lang.Object.

String

Endpoint Options

The Caffeine LoadCache endpoint is configured using URI syntax:

caffeine-loadcache:cacheName

With the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

cacheName (producer)

Required the cache name.

String

Query Parameters (14 parameters)

Name Description Default Type

action (producer)

To configure the default cache action. If an action is set in the message header, then the operation from the header takes precedence.

Enum values:

  • GET

  • GET_ALL

  • PUT

  • PUT_ALL

  • INVALIDATE

  • INVALIDATE_ALL

  • CLEANUP

  • AS_MAP

String

createCacheIfNotExist (producer)

Automatic create the Caffeine cache if none has been configured or exists in the registry.

true

boolean

evictionType (producer)

Set the eviction Type for this cache.

Enum values:

  • size_based

  • time_based

SIZE_BASED

EvictionType

expireAfterAccessTime (producer)

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, the most recent replacement of its value, or its last read. Access time is reset by all cache read and write operations. The unit is in seconds.

300

int

expireAfterWriteTime (producer)

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, or the most recent replacement of its value. The unit is in seconds.

300

int

initialCapacity (producer)

Sets the minimum total size for the internal data structures. Providing a large enough estimate at construction time avoids the need for expensive resizing operations later, but setting this value unnecessarily high wastes memory.

Integer

key (producer)

To configure the default action key. If a key is set in the message header, then the key from the header takes precedence.

String

maximumSize (producer)

Specifies the maximum number of entries the cache may contain. Note that the cache may evict an entry before this limit is exceeded or temporarily exceed the threshold while evicting. As the cache size grows close to the maximum, the cache evicts entries that are less likely to be used again. For example, the cache may evict an entry because it hasn’t been used recently or very often. When size is zero, elements will be evicted immediately after being loaded into the cache. This can be useful in testing or to disable caching temporarily without a code change. As eviction is scheduled on the configured executor, tests may instead prefer to configure the cache to execute tasks directly on the same thread.

Integer

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

cacheLoader (advanced)

To configure a CacheLoader in case of a LoadCache use.

CacheLoader

removalListener (advanced)

Set a specific removal Listener for the cache.

RemovalListener

statsCounter (advanced)

Set a specific Stats Counter for the cache stats.

StatsCounter

statsEnabled (advanced)

To enable stats on the cache.

false

boolean

valueType (advanced)

The cache value type, default java.lang.Object.

String

Message Headers

The Caffeine LoadCache component supports 7 message header(s), which is/are listed below:

Name Description Default Type

CamelCaffeineAction (producer)

Constant: ACTION

The action to execute. Possible values: CLEANUP PUT PUT_ALL GET GET_ALL INVALIDATE INVALIDATE_ALL AS_MAP.

String

CamelCaffeineActionHasResult (producer)

Constant: ACTION_HAS_RESULT

The flag indicating whether the action has a result or not.

Boolean

CamelCaffeineActionSucceeded (producer)

Constant: ACTION_SUCCEEDED

The flag indicating whether the action was successful or not.

Boolean

CamelCaffeineKey (producer)

Constant: KEY

The key for all actions on a single entry.

CamelCaffeineKeys (producer)

Constant: KEYS

The keys to get (GET_ALL), to invalidate (INVALIDATE_ALL) or existing (AS_MAP) according to the action.

Set

CamelCaffeineValue (producer)

Constant: VALUE

The value of key for all put actions (PUT or PUT_ALL).

CamelCaffeineOldValue (producer)

Constant: OLD_VALUE

The old value returned according to the action.

Spring Boot Auto-Configuration

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

The component supports 34 options, which are listed below.

Name Description Default Type

camel.component.caffeine-cache.action

To configure the default cache action. If an action is set in the message header, then the operation from the header takes precedence.

String

camel.component.caffeine-cache.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.caffeine-cache.cache-loader

To configure a CacheLoader in case of a LoadCache use. The option is a com.github.benmanes.caffeine.cache.CacheLoader type.

CacheLoader

camel.component.caffeine-cache.configuration

Sets the global component configuration. The option is a org.apache.camel.component.caffeine.CaffeineConfiguration type.

CaffeineConfiguration

camel.component.caffeine-cache.create-cache-if-not-exist

Automatic create the Caffeine cache if none has been configured or exists in the registry.

true

Boolean

camel.component.caffeine-cache.enabled

Whether to enable auto configuration of the caffeine-cache component. This is enabled by default.

Boolean

camel.component.caffeine-cache.eviction-type

Set the eviction Type for this cache.

EvictionType

camel.component.caffeine-cache.expire-after-access-time

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, the most recent replacement of its value, or its last read. Access time is reset by all cache read and write operations. The unit is in seconds.

300

Integer

camel.component.caffeine-cache.expire-after-write-time

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, or the most recent replacement of its value. The unit is in seconds.

300

Integer

camel.component.caffeine-cache.initial-capacity

Sets the minimum total size for the internal data structures. Providing a large enough estimate at construction time avoids the need for expensive resizing operations later, but setting this value unnecessarily high wastes memory.

Integer

camel.component.caffeine-cache.key

To configure the default action key. If a key is set in the message header, then the key from the header takes precedence.

String

camel.component.caffeine-cache.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.caffeine-cache.maximum-size

Specifies the maximum number of entries the cache may contain. Note that the cache may evict an entry before this limit is exceeded or temporarily exceed the threshold while evicting. As the cache size grows close to the maximum, the cache evicts entries that are less likely to be used again. For example, the cache may evict an entry because it hasn’t been used recently or very often. When size is zero, elements will be evicted immediately after being loaded into the cache. This can be useful in testing or to disable caching temporarily without a code change. As eviction is scheduled on the configured executor, tests may instead prefer to configure the cache to execute tasks directly on the same thread.

Integer

camel.component.caffeine-cache.removal-listener

Set a specific removal Listener for the cache. The option is a com.github.benmanes.caffeine.cache.RemovalListener type.

RemovalListener

camel.component.caffeine-cache.stats-counter

Set a specific Stats Counter for the cache stats. The option is a com.github.benmanes.caffeine.cache.stats.StatsCounter type.

StatsCounter

camel.component.caffeine-cache.stats-enabled

To enable stats on the cache.

false

Boolean

camel.component.caffeine-cache.value-type

The cache value type, default java.lang.Object.

String

camel.component.caffeine-loadcache.action

To configure the default cache action. If an action is set in the message header, then the operation from the header takes precedence.

String

camel.component.caffeine-loadcache.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.caffeine-loadcache.cache-loader

To configure a CacheLoader in case of a LoadCache use. The option is a com.github.benmanes.caffeine.cache.CacheLoader type.

CacheLoader

camel.component.caffeine-loadcache.configuration

Sets the global component configuration. The option is a org.apache.camel.component.caffeine.CaffeineConfiguration type.

CaffeineConfiguration

camel.component.caffeine-loadcache.create-cache-if-not-exist

Automatic create the Caffeine cache if none has been configured or exists in the registry.

true

Boolean

camel.component.caffeine-loadcache.enabled

Whether to enable auto configuration of the caffeine-loadcache component. This is enabled by default.

Boolean

camel.component.caffeine-loadcache.eviction-type

Set the eviction Type for this cache.

EvictionType

camel.component.caffeine-loadcache.expire-after-access-time

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, the most recent replacement of its value, or its last read. Access time is reset by all cache read and write operations. The unit is in seconds.

300

Integer

camel.component.caffeine-loadcache.expire-after-write-time

Specifies that each entry should be automatically removed from the cache once a fixed duration has elapsed after the entry’s creation, or the most recent replacement of its value. The unit is in seconds.

300

Integer

camel.component.caffeine-loadcache.initial-capacity

Sets the minimum total size for the internal data structures. Providing a large enough estimate at construction time avoids the need for expensive resizing operations later, but setting this value unnecessarily high wastes memory.

Integer

camel.component.caffeine-loadcache.key

To configure the default action key. If a key is set in the message header, then the key from the header takes precedence.

String

camel.component.caffeine-loadcache.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.caffeine-loadcache.maximum-size

Specifies the maximum number of entries the cache may contain. Note that the cache may evict an entry before this limit is exceeded or temporarily exceed the threshold while evicting. As the cache size grows close to the maximum, the cache evicts entries that are less likely to be used again. For example, the cache may evict an entry because it hasn’t been used recently or very often. When size is zero, elements will be evicted immediately after being loaded into the cache. This can be useful in testing or to disable caching temporarily without a code change. As eviction is scheduled on the configured executor, tests may instead prefer to configure the cache to execute tasks directly on the same thread.

Integer

camel.component.caffeine-loadcache.removal-listener

Set a specific removal Listener for the cache. The option is a com.github.benmanes.caffeine.cache.RemovalListener type.

RemovalListener

camel.component.caffeine-loadcache.stats-counter

Set a specific Stats Counter for the cache stats. The option is a com.github.benmanes.caffeine.cache.stats.StatsCounter type.

StatsCounter

camel.component.caffeine-loadcache.stats-enabled

To enable stats on the cache.

false

Boolean

camel.component.caffeine-loadcache.value-type

The cache value type, default java.lang.Object.

String
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