Home
User documentation

General topics: - Caching Terms - Caching Concepts - Caching Patterns

Resources
Ehcache 3.1 added clustering support but this is not yet compatible with cache-through.

Write-Through Cache

CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder().build(true);

final Cache<Long, String> writeThroughCache = cacheManager.createCache("writeThroughCache",
    CacheConfigurationBuilder.newCacheConfigurationBuilder(Long.class, String.class, ResourcePoolsBuilder.heap(10))
        .withLoaderWriter(new SampleLoaderWriter<Long, String>(singletonMap(41L, "zero"))) (1)
        .build());

assertThat(writeThroughCache.get(41L), is("zero"));
writeThroughCache.put(42L, "one");
assertThat(writeThroughCache.get(42L), equalTo("one"));

cacheManager.close();
1 If you wish to use a cache in read-through/write-through caching pattern, you’ll have to implement a CacheLoaderWriter and configure it.

Write-Behind Cache

CacheManager cacheManager = CacheManagerBuilder.newCacheManagerBuilder().build(true);

final Cache<Long, String> writeBehindCache = cacheManager.createCache("writeBehindCache",
    CacheConfigurationBuilder.newCacheConfigurationBuilder(Long.class, String.class, ResourcePoolsBuilder.heap(10))
        .withLoaderWriter(new SampleLoaderWriter<Long, String>(singletonMap(41L, "zero"))) (1)
        .add(WriteBehindConfigurationBuilder (2)
            .newBatchedWriteBehindConfiguration(1, TimeUnit.SECONDS, 3)(3)
            .queueSize(3)(4)
            .concurrencyLevel(1) (5)
            .enableCoalescing()) (6)
        .build());

assertThat(writeBehindCache.get(41L), is("zero"));
writeBehindCache.put(42L, "one");
writeBehindCache.put(43L, "two");
writeBehindCache.put(42L, "This goes for the record");
assertThat(writeBehindCache.get(42L), equalTo("This goes for the record"));

cacheManager.close();
1 A Cache can be used in write-behind pattern as well. You will have to implement a CacheLoaderWriter and configure it.
2 Additionally, register a WriteBehindConfiguration on the Cache by using the WriteBehindConfigurationBuilder.
3 Here we configure write behind with a batch size of 3 and a max wait time of 1 second.
4 We also set the maximum size of the writebehind queue.
5 Define the concurrency level of writebehind queue, at a time these many writer threads will update the underlying resource asynchronously.
6 Enable the write coalescing behavior, which ensures that only one update per key per batch hits the underlying resource.