ehcache persist to disk issues

Question

I want to do something with ehcache in Java that I think should be extremely simple, but I've spent enough time frustrating myself with the docs...

1. Write a value to a disk persistent cache. Shut down.

2. Start up again and read that value.

Here is my Java function:

private static void testCacheWrite() {    // create the cache manager from our configuration   URL url = TestBed.class.getClass().getResource("/resource/ehcache.xml");   CacheManager manager = CacheManager.create(url);   // check to see if our cache exits, if it doesn't create it   Cache testCache = null;   if (!manager.cacheExists("test")) {     System.out.println("No cache found. Creating cache...");     int maxElements = 50000;     testCache = new Cache("test", maxElements,       MemoryStoreEvictionPolicy.LFU, true, null, true, 60, 30,       true, Cache.DEFAULT_EXPIRY_THREAD_INTERVAL_SECONDS, null);     manager.addCache(testCache);     // add an element to persist     Element el = new Element("key", "value");     testCache.put(el);     testCache.flush();     System.out.println("Cache to disk. Cache size on disk: " +       testCache.getDiskStoreSize());   } else {     // cache exists so load it     testCache = manager.getCache("test");     Element el = testCache.get("key");     if (null == el) {       System.out.print("Value was null");       return;     }     String value = (String) el.getObjectValue();     System.out.println("Value is: " + value);   }   manager.shutdown(); } 

And here is my cache configuration (ehcache.xml):

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"   xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">   <diskStore path="C:/mycache"/><!-- java.io.tmpdir -->   <defaultCache     maxElementsInMemory="10000"     eternal="true"     timeToIdleSeconds="120"     timeToLiveSeconds="120"     overflowToDisk="true"     maxElementsOnDisk="10000000"     diskPersistent="true"     diskExpiryThreadIntervalSeconds="120"     memoryStoreEvictionPolicy="LRU" /> </ehcache> 

Even though I see test.index and test.data files on disk after the first run, output from this function is always the following (it never seems to load the cache from disk):

No cache found. Creating cache...
Cache to disk. Cache size on disk: 2

I must be doing something dumb here, but I 'm not sure what!

Answer 1

Okay, well what I did to fix this was configure my cache using the configuration file. Here is the updated config:

<ehcache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"           xsi:noNamespaceSchemaLocation="../config/ehcache.xsd">      <diskStore path="C:/mycache" />      <defaultCache         maxElementsInMemory="10000"          eternal="true"         timeToIdleSeconds="120"          timeToLiveSeconds="120"          overflowToDisk="true"         maxElementsOnDisk="10000000"          diskPersistent="true"         diskExpiryThreadIntervalSeconds="120"          memoryStoreEvictionPolicy="LRU" />      <cache          name="test"          maxElementsInMemory="500"          eternal="true"         overflowToDisk="true"          timeToIdleSeconds="300"          timeToLiveSeconds="600"         diskPersistent="true"          diskExpiryThreadIntervalSeconds="1"         memoryStoreEvictionPolicy="LFU" />  </ehcache> 

So basically I didn't use the constructor to define the cache.

I suppose this will work, but I still wonder why programatically defined caches can't persist on disk (especially since they are still written to disk!).

Thanks for the comments guys.