Question

I’m trying to do a simple test with ehcache – put an element into the cache, flush and shutdown the cache. Then reload all the beans with spring (also initializes cachemanager). Do a cache.get and retrieve previously written values.

EhCache Element’s value is a some serializable class called DOM which comprises a field ConcurrentHasMap

I create 3 DOM instances: d1, d2, d3
d1 (has a map with 3 values: t1, t2, t3)
d2 (has a map with 2 values: x1, x2)
d3 (has a map with 2 values: s1, s2)

I call:

cachemanager and cache are created with spring
cache.put(new Element(1,d1))
cache.put(new Element(2,d2))
cache.put(new Element(3,d3))
cache.flush();
cacheManager.shutdown();
cache = null
cacheManager = null

I call to load spring application context (which creates cacheManager and cache)

I call:

actualD1 = cache.get(1)
actualD2 = cache.get(2)
actualD3 = cache.get(3)

I receive the DOM objects into the actualD1, actualD2 and actualD3 variables
But the problem is that now each of them has only one value

actualD1 (has a map with 1 value: t1)
actualD2 (has a map with 1 value: x1)
actualD3 (has a map with 1 value: s1)

What could be the problem!???

Here is my ehcache.xml file:

<defaultCache
       maxElementsInMemory="1000000"
       eternal="false"
       diskSpoolBufferSizeMB="100"
       overflowToDisk="true"
       clearOnFlush="false"
       copyOnRead="false"
       copyOnWrite="false"
       diskExpiryThreadIntervalSeconds="300"
       diskPersistent="true">
</defaultCache>

Here is how I create a cacheManager (this method is called in startup from spring)

protected def checkAndCreateCacheManagerIfNeeded() =
{
    if (cacheManager == null)
    {
        synchronized
        {
            if (cacheManager == null)
            {
                cacheManager = CacheManager.create(ehCacheConfigFile);
            }
        }
    };
};

The following code creates the cache:

protected def getOrCreateCache(cacheName : String) =
{
    checkAndCreateCacheManagerIfNeeded();
    var cache = cacheManager.getEhcache(cacheName);
    if (cache == null)
    {
        cacheManager.synchronized
        {
            cache = cacheManager.getEhcache(cacheName);
            if (cache == null)
            {
                cache = cacheManager.addCacheIfAbsent(cacheName);
            }
        }
    };
    cache;
};

Answer 1

The problem was adding t1, t2, t3 to d1 without putting the updated d1 to the cache. After each addition of the value to map. One must add the call:

cache.put(d1Element)