第18章 Cache

<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>

cache://cacheName[?options]

from("cache://MyApplicationCache" +
          "?maxElementsInMemory=1000" +
          "&memoryStoreEvictionPolicy=" +
              "MemoryStoreEvictionPolicy.LFU" +
          "&overflowToDisk=true" +
          "&eternal=true" +
          "&timeToLiveSeconds=300" +
          "&timeToIdleSeconds=true" +
          "&diskPersistent=true" +
          "&diskExpiryThreadIntervalSeconds=300")

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")
   }
};

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")
   }
};

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")
   }
};

RouteBuilder builder = new RouteBuilder() {
    public void configure() {
     from("direct:start")
     .setHeader(CacheConstants.CACHE_OPERATION, constant(CacheConstants.CACHE_DELETEALL))
     .to("cache://TestCache1");
    }
};

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
        }
     })
   }
};

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");
   }
};

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");

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();

<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>

ManagementService.registerMBeans(CacheManager.getInstance(), mbeanServer, true, true, true, true);