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

The component level is the highest level which holds general and common configurations that are inherited by the endpoints. 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.

Configuring components can be done with the Component DSL, in a configuration file (application.properties|yaml), or directly with Java code.

Configuring Endpoint Options

Where you find yourself configuring the most is on endpoints, as endpoints often have many options, which allows you to configure what you need the endpoint to do. The options are also categorized into whether the endpoint is used as consumer (from) or as a producer (to), or used for both.

Configuring endpoints is most often done directly in the endpoint URI as path and query parameters. You can also use the Endpoint DSL as a type safe way of configuring endpoints.

A good practice when configuring options is to use Property Placeholders, which allows to not hardcode urls, port numbers, sensitive information, and other settings. In other words placeholders allows to externalize the configuration from your code, and gives more flexibility and reuse.

The following two sections lists 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.

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.

boolean

eventFiring (consumer)

Set the delivery mode (synchronous, asynchronous).

Enum values:

  • ASYNCHRONOUS

  • SYNCHRONOUS

EventFiring

eventOrdering (consumer)

Set the delivery mode (ordered, unordered).

Enum values:

  • UNORDERED

  • 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.

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.

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.

boolean

bridgeErrorHandler (consumer)

Allows for bridging the consumer to the Camel routing Error Handler, which mean any exceptions occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.

boolean

eventFiring (consumer)

Set the delivery mode (synchronous, asynchronous).

Enum values:

  • ASYNCHRONOUS

  • SYNCHRONOUS

EventFiring

eventOrdering (consumer)

Set the delivery mode (ordered, unordered).

Enum values:

  • UNORDERED

  • 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

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

  • InOptionalOut

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)

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.

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 Camel

Header Type Description

CamelEhcacheAction

String

The operation to be perfomed on the cache, valid options are:

* CLEAR * PUT * PUT_ALL * PUT_IF_ABSENT * GET * GET_ALL * REMOVE * REMOVE_ALL * REPLACE

CamelEhcacheActionHasResult

Boolean

Set to true if the action has a result

CamelEhcacheActionSucceeded

Boolean

Set to true if the actionsuccedded

CamelEhcacheKey

Object

The cache key used for an action

CamelEhcacheKeys

Set<Object>

A list of keys, used in

* PUT_ALL * GET_ALL * REMOVE_ALL

CamelEhcacheValue

Object

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

CamelEhcacheOldValue

Object

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

CamelEhcacheEventType

EventType

The type of event received

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 21 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 occurred while the consumer is trying to pickup incoming messages, or the likes, will now be processed as a message and handled by the routing Error Handler. 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.

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).

EventFiring

camel.component.ehcache.event-ordering

Set the delivery mode (ordered, unordered).

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

To configure the default action key. If a key is set in the message header, then the key from the header takes precedence. The option is a java.lang.Object type.

Object

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