Ehcache

Since Camel 2.18

Both producer and consumer are supported

The Ehcache component enables you to perform caching operations using Ehcache 3 as the Cache Implementation.

The Cache consumer is an event based consumer and can be used to listen and respond to specific cache activities.

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

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

URI format

ehcache://cacheName[?options]

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 Ehcache component supports 16 options, which are listed below.

Name Description Default Type

cacheManager (common)

The cache manager.

CacheManager

cacheManagerConfiguration (common)

The cache manager configuration.

Configuration

configurationUri (common)

URI pointing to the Ehcache XML configuration file’s location.

String

createCacheIfNotExist (common)

Configure if a cache need to be created if it does exist or can’t be pre-configured.

true

boolean

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

eventFiring (consumer)

Set the delivery mode (synchronous, asynchronous).

Enum values:

  • ASYNCHRONOUS

  • SYNCHRONOUS

ASYNCHRONOUS

EventFiring

eventOrdering (consumer)

Set the delivery mode (ordered, unordered).

Enum values:

  • UNORDERED

  • ORDERED

ORDERED

EventOrdering

eventTypes (consumer)

Set the type of events to listen for (EVICTED,EXPIRED,REMOVED,CREATED,UPDATED). You can specify multiple entries separated by comma.

Enum values:

  • EVICTED

  • EXPIRED

  • REMOVED

  • CREATED

  • UPDATED

String

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.

String

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.

Object

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

configuration (advanced)

The default cache configuration to be used to create caches.

CacheConfiguration

configurations (advanced)

A map of cache configuration to be used to create caches.

Map

keyType (advanced)

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

String

valueType (advanced)

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

String

Endpoint Options

The Ehcache endpoint is configured using URI syntax:

ehcache:cacheName

With the following path and query parameters:

Path Parameters (1 parameters)

Name Description Default Type

cacheName (common)

Required the cache name.

String

Query Parameters (17 parameters)

Name Description Default Type

cacheManager (common)

The cache manager.

CacheManager

cacheManagerConfiguration (common)

The cache manager configuration.

Configuration

configurationUri (common)

URI pointing to the Ehcache XML configuration file’s location.

String

createCacheIfNotExist (common)

Configure if a cache need to be created if it does exist or can’t be pre-configured.

true

boolean

eventFiring (consumer)

Set the delivery mode (synchronous, asynchronous).

Enum values:

  • ASYNCHRONOUS

  • SYNCHRONOUS

ASYNCHRONOUS

EventFiring

eventOrdering (consumer)

Set the delivery mode (ordered, unordered).

Enum values:

  • UNORDERED

  • ORDERED

ORDERED

EventOrdering

eventTypes (consumer)

Set the type of events to listen for (EVICTED,EXPIRED,REMOVED,CREATED,UPDATED). You can specify multiple entries separated by comma.

Enum values:

  • EVICTED

  • EXPIRED

  • REMOVED

  • CREATED

  • UPDATED

String

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

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.

String

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.

Object

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

configuration (advanced)

The default cache configuration to be used to create caches.

CacheConfiguration

configurations (advanced)

A map of cache configuration to be used to create caches.

Map

keyType (advanced)

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

String

valueType (advanced)

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

String

Message Headers

The Ehcache component supports 8 message header(s), which is/are listed below:

Name Description Default Type

CamelEhcacheAction (common)

Constant: ACTION

The operation to be performed on the cache, valid options are: CLEAR PUT PUT_ALL PUT_IF_ABSENT GET GET_ALL REMOVE REMOVE_ALL REPLACE.

String

CamelEhcacheActionHasResult (common)

Constant: ACTION_HAS_RESULT

Set to true if the action has a result.

Boolean

CamelEhcacheActionSucceeded (common)

Constant: ACTION_SUCCEEDED

Set to true if the action was successful.

Boolean

CamelEhcacheKey (common)

Constant: KEY

The cache key used for an action.

Object

CamelEhcacheKeys (common)

Constant: KEYS

A list of keys, used in PUT_ALL GET_ALL REMOVE_ALL.

Set

CamelEhcacheValue (common)

Constant: VALUE

The value to put in the cache or the result of an operation.

Object

CamelEhcacheOldValue (common)

Constant: OLD_VALUE

The old value associated to a key for actions like PUT_IF_ABSENT or the Object used for comparison for actions like REPLACE.

Object

CamelEhcacheEventType (common)

Constant: EVENT_TYPE

The type of event received.

EventType

Examples

Ehcache based idempotent repository example:

CacheManager manager = CacheManagerBuilder.newCacheManager(new XmlConfiguration("ehcache.xml"));
EhcacheIdempotentRepository repo = new EhcacheIdempotentRepository(manager, "idempotent-cache");

from("direct:in")
    .idempotentConsumer(header("messageId"), idempotentRepo)
    .to("mock:out");

Ehcache based aggregation repository example:

public class EhcacheAggregationRepositoryRoutesTest extends CamelTestSupport {
    private static final String ENDPOINT_MOCK = "mock:result";
    private static final String ENDPOINT_DIRECT = "direct:one";
    private static final int[] VALUES = generateRandomArrayOfInt(10, 0, 30);
    private static final int SUM = IntStream.of(VALUES).reduce(0, (a, b) -> a + b);
    private static final String CORRELATOR = "CORRELATOR";

    @EndpointInject(ENDPOINT_MOCK)
    private MockEndpoint mock;

    @Produce(uri = ENDPOINT_DIRECT)
    private ProducerTemplate producer;

    @Test
    public void checkAggregationFromOneRoute() throws Exception {
        mock.expectedMessageCount(VALUES.length);
        mock.expectedBodiesReceived(SUM);

        IntStream.of(VALUES).forEach(
            i -> producer.sendBodyAndHeader(i, CORRELATOR, CORRELATOR)
        );

        mock.assertIsSatisfied();
    }

    private Exchange aggregate(Exchange oldExchange, Exchange newExchange) {
        if (oldExchange == null) {
            return newExchange;
        } else {
            Integer n = newExchange.getIn().getBody(Integer.class);
            Integer o = oldExchange.getIn().getBody(Integer.class);
            Integer v = (o == null ? 0 : o) + (n == null ? 0 : n);

            oldExchange.getIn().setBody(v, Integer.class);

            return oldExchange;
        }
    }

    @Override
    protected RoutesBuilder createRouteBuilder() throws Exception {
        return new RouteBuilder() {
            @Override
            public void configure() throws Exception {
                from(ENDPOINT_DIRECT)
                    .routeId("AggregatingRouteOne")
                    .aggregate(header(CORRELATOR))
                    .aggregationRepository(createAggregateRepository())
                    .aggregationStrategy(EhcacheAggregationRepositoryRoutesTest.this::aggregate)
                    .completionSize(VALUES.length)
                        .to("log:org.apache.camel.component.ehcache.processor.aggregate.level=INFO&showAll=true&mulltiline=true")
                        .to(ENDPOINT_MOCK);
            }
        };
    }

    protected EhcacheAggregationRepository createAggregateRepository() throws Exception {
        CacheManager cacheManager = CacheManagerBuilder.newCacheManager(new XmlConfiguration("ehcache.xml"));
        cacheManager.init();

        EhcacheAggregationRepository repository = new EhcacheAggregationRepository();
        repository.setCacheManager(cacheManager);
        repository.setCacheName("aggregate");

        return repository;
    }
}

Spring Boot Auto-Configuration

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

The component supports 20 options, which are listed below.

Name Description Default Type

camel.component.ehcache.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.ehcache.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.ehcache.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.ehcache.cache-manager

The cache manager. The option is a org.ehcache.CacheManager type.

CacheManager

camel.component.ehcache.cache-manager-configuration

The cache manager configuration. The option is a org.ehcache.config.Configuration type.

Configuration

camel.component.ehcache.configuration

The default cache configuration to be used to create caches. The option is a org.ehcache.config.CacheConfiguration type.

CacheConfiguration

camel.component.ehcache.configuration-uri

URI pointing to the Ehcache XML configuration file’s location.

String

camel.component.ehcache.configurations

A map of cache configuration to be used to create caches.

Map

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

Configure if a cache need to be created if it does exist or can’t be pre-configured.

true

Boolean

camel.component.ehcache.customizer.cache-configuration.enabled

Enable or disable the cache-configuration customizer.

true

Boolean

camel.component.ehcache.customizer.cache-configuration.mode

Configure if the cache configurations have be added or they have to replace those already configured on the component.

append

CacheConfigurationCustomizerConfiguration$Mode

camel.component.ehcache.customizer.cache-manager.enabled

Enable or disable the cache-manager customizer.

true

Boolean

camel.component.ehcache.customizer.cache-manager.override

Configure if the cache manager eventually set on the component should be overridden by the customizer.

false

Boolean

camel.component.ehcache.enabled

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

Boolean

camel.component.ehcache.event-firing

Set the delivery mode (synchronous, asynchronous).

asynchronous

EventFiring

camel.component.ehcache.event-ordering

Set the delivery mode (ordered, unordered).

ordered

EventOrdering

camel.component.ehcache.event-types

Set the type of events to listen for (EVICTED,EXPIRED,REMOVED,CREATED,UPDATED). You can specify multiple entries separated by comma.

String

camel.component.ehcache.key-type

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

String

camel.component.ehcache.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.ehcache.value-type

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

String
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