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Maven users will need to add the following dependency to their pom.xml for this component:
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<dependency>
<groupId>org.apache.camel</groupId>
<artifactId>camel-cache</artifactId>
<version>x.x.x</version>
<!-- use the same version as your Camel core version -->
</dependency>
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URI format
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cache://cacheName[?options]
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You can append query options to the URI in the following format, ?option=value&option=#beanRef&...
Options
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{div:class=confluenceTableSmall}
|| Name || Default Value || Description ||
| {{maxElementsInMemory}} | {{1000}} | The number of elements that may be stored in the defined cache |
| {{memoryStoreEvictionPolicy}} | {{MemoryStoreEvictionPolicy.LFU}} | The number of elements that may be stored in the defined cache. Options include
- MemoryStoreEvictionPolicy.LFU - Least frequently used
- MemoryStoreEvictionPolicy.LRU - Least recently used
- MemoryStoreEvictionPolicy.FIFO - first in first out, the oldest element by creation time |
| {{overflowToDisk}} | {{true}} | Specifies whether cache may overflow to disk |
| {{eternal}} | {{false}} | Sets whether elements are eternal. If eternal, timeouts are ignored and the\\
element never expires. |
| {{timeToLiveSeconds}} | {{300}} | The maximum time between creation time and when an element expires.\\
Is used only if the element is not eternal |
| {{timeToIdleSeconds}} | {{300}} | The maximum amount of time between accesses before an element expires |
| {{diskPersistent}} | {{false}} | Whether the disk store persists between restarts of the Virtual Machine. |
| {{diskExpiryThreadIntervalSeconds}} | {{120}} | The number of seconds between runs of the disk expiry thread. |
| {{cacheManagerFactory}} | {{null}} | *Camel 2.8:* If you want to use a custom factory which instantiates and creates the EHCache {{net.sf.ehcache.CacheManager}}. \\ \\ _Type:_ abstract org.apache.camel.component.cache.CacheManagerFactory |
| {{eventListenerRegistry}} | {{null}} | *Camel 2.8:* Sets a list of EHCache {{net.sf.ehcache.event.CacheEventListener}} for all new caches\- no need to define it per cache in EHCache xml config anymore. \\ \\ _Type:_ org.apache.camel.component.cache.CacheEventListenerRegistry |
| {{cacheLoaderRegistry}} | {{null}} | *Camel 2.8:* Sets a list of {{org.apache.camel.component.cache.CacheLoaderWrapper}} that extends EHCache {{net.sf.ehcache.loader.CacheLoader}} for all new caches\- no need to define it per cache in EHCache xml config anymore. \\ \\ _Type:_ org.apache.camel.component.cache.CacheLoaderRegistry |
| {{key}} | {{null}} | *Camel 2.10:* To configure using a cache key by default. If a key is provided in the message header, then the key from the header takes precedence. |
| {{operation}} | {{null}} | *Camel 2.10:* To configure using an cache operation by default. If an operation in the message header, then the operation by default. If an operation in the message header, then the operation from the header takes precedence. |
{div} from the header takes precedence. | |
Cache Component options
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|| Name || Default Value || Description ||
| {{configuration}} | | To use a custom {{org.apache.camel.component.cache.CacheConfiguration}} configuration. |
| {{cacheManagerFactory}} | | To use a custom {{org.apache.camel.component.cache.CacheManagerFactory}}. |
| {{configurationFile}} | | *Camel 2.13/2.12.3:* To configure the location of the {{ehcache.xml}} file to use, such as {{classpath:com/foo/mycache.xml}} to load from classpath. By default the configuration is loaded from {{classpath:ehcache.xml}}. | |
Sending/Receiving Messages to/from the cache
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Example 1: Configuring the cache
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from("cache://MyApplicationCache" +
"?maxElementsInMemory=1000" +
"&memoryStoreEvictionPolicy=" +
"MemoryStoreEvictionPolicy.LFU" +
"&overflowToDisk=true" +
"&eternal=true" +
"&timeToLiveSeconds=300" +
"&timeToIdleSeconds=true" +
"&diskPersistent=true" +
"&diskExpiryThreadIntervalSeconds=300")
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Example 2: Adding keys to the cache
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start")
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_ADD))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))
.to("cache://TestCache1")
}
};
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Example 2: Updating existing keys in a cache
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start")
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_UPDATE))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))
.to("cache://TestCache1")
}
};
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Example 3: Deleting existing keys in a cache
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start")
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_DELETE))
.setHeader(CacheConstants.CACHE_KEY", constant("Ralph_Waldo_Emerson"))
.to("cache://TestCache1")
}
};
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Example 4: Deleting all existing keys in a cache
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("direct:start")
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_DELETEALL))
.to("cache://TestCache1");
}
};
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Example 5: Notifying any changes registering in a Cache to Processors and other Producers
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
from("cache://TestCache1")
.process(new Processor() {
public void process(Exchange exchange)
throws Exception {
String operation = (String) exchange.getIn().getHeader(CacheConstants.CACHE_OPERATION);
String key = (String) exchange.getIn().getHeader(CacheConstants.CACHE_KEY);
Object body = exchange.getIn().getBody();
// Do something
}
})
}
};
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Example 6: Using Processors to selectively replace payload with cache values
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RouteBuilder builder = new RouteBuilder() {
public void configure() {
//Message Body Replacer
from("cache://TestCache1")
.filter(header(CacheConstants.CACHE_KEY).isEqualTo("greeting"))
.process(new CacheBasedMessageBodyReplacer("cache://TestCache1","farewell"))
.to("direct:next");
//Message Token replacer
from("cache://TestCache1")
.filter(header(CacheConstants.CACHE_KEY).isEqualTo("quote"))
.process(new CacheBasedTokenReplacer("cache://TestCache1","novel","#novel#"))
.process(new CacheBasedTokenReplacer("cache://TestCache1","author","#author#"))
.process(new CacheBasedTokenReplacer("cache://TestCache1","number","#number#"))
.to("direct:next");
//Message XPath replacer
from("cache://TestCache1").
.filter(header(CacheConstants.CACHE_KEY).isEqualTo("XML_FRAGMENT"))
.process(new CacheBasedXPathReplacer("cache://TestCache1","book1","/books/book1"))
.process (new CacheBasedXPathReplacer("cache://TestCache1","book2","/books/book2"))
.to("direct:next");
}
};
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Example 7: Getting an entry from the Cache
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from("direct:start")
// Prepare headers
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_GET))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson")).
.to("cache://TestCache1").
// Check if entry was not found
.choice().when(header(CacheConstants.CACHE_ELEMENT_WAS_FOUND).isNull()).
// If not found, get the payload and put it to cache
.to("cxf:bean:someHeavyweightOperation").
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_ADD))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))
.to("cache://TestCache1")
.end()
.to("direct:nextPhase");
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Note: The CHECK command tests existence of an entry in the cache but doesn't place a message in the body.
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from("direct:start")
// Prepare headers
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_CHECK))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson")).
.to("cache://TestCache1").
// Check if entry was not found
.choice().when(header(CacheConstants.CACHE_ELEMENT_WAS_FOUND).isNull()).
// If not found, get the payload and put it to cache
.to("cxf:bean:someHeavyweightOperation").
.setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_OPERATION_ADD))
.setHeader(CacheConstants.CACHE_KEY, constant("Ralph_Waldo_Emerson"))
.to("cache://TestCache1")
.end();
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Here's a snippet on how to expose them via JMX in a Spring application context:
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<bean id="ehCacheManagementService" class="net.sf.ehcache.management.ManagementService" init-method="init" lazy-init="false">
<constructor-arg>
<bean class="net.sf.ehcache.CacheManager" factory-method="getInstance"/>
</constructor-arg>
<constructor-arg>
<bean class="org.springframework.jmx.support.JmxUtils" factory-method="locateMBeanServer"/>
</constructor-arg>
<constructor-arg value="true"/>
<constructor-arg value="true"/>
<constructor-arg value="true"/>
<constructor-arg value="true"/>
</bean>
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Of course you can do the same thing in straight Java:
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ManagementService.registerMBeans(CacheManager.getInstance(), mbeanServer, true, true, true, true);
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