Package org.apache.hc.client5.http.impl.cache.memcached

Class MemcachedHttpAsyncCacheStorage

java.lang.Object
org.apache.hc.client5.http.impl.cache.AbstractSerializingAsyncCacheStorage<byte[],CAS>
org.apache.hc.client5.http.impl.cache.AbstractBinaryAsyncCacheStorage<net.spy.memcached.CASValue<Object>>
org.apache.hc.client5.http.impl.cache.memcached.MemcachedHttpAsyncCacheStorage
All Implemented Interfaces:
HttpAsyncCacheStorage
public class MemcachedHttpAsyncCacheStorage extends AbstractBinaryAsyncCacheStorage<net.spy.memcached.CASValue<Object>>

This class is a storage backend that uses an external memcached for storing cached origin responses. This storage option provides a couple of interesting advantages over the default in-memory storage backend:

  1. in-memory cached objects can survive an application restart since they are held in a separate process
  2. it becomes possible for several cooperating applications to share a large memcached farm together

Note that in a shared memcached pool setting you may wish to make use of the Ketama consistent hashing algorithm to reduce the number of cache misses that might result if one of the memcached cluster members fails (see the KetamaConnectionFactory).

Because memcached places limits on the size of its keys, we need to introduce a key hashing scheme to map the annotated URLs the higher-level caching HTTP client wants to use as keys onto ones that are suitable for use with memcached. Please see KeyHashingScheme if you would like to use something other than the provided SHA256KeyHashingScheme.

Please refer to the memcached documentation and in particular to the documentation for the spymemcached documentation for details about how to set up and configure memcached and the Java client used here, respectively.

Since:
5.0

  • Field Details

    • client

      private final net.spy.memcached.MemcachedClient client

    • keyHashingScheme

      private final KeyHashingScheme keyHashingScheme

  • Constructor Details

    • MemcachedHttpAsyncCacheStorage

      public MemcachedHttpAsyncCacheStorage(InetSocketAddress address) throws IOException
      Create a storage backend talking to a memcached instance listening on the specified host and port. This is useful if you just have a single local memcached instance running on the same machine as your application, for example.
      Parameters:
      address - where the memcached daemon is running
      Throws:
      IOException - in case of an error

    • MemcachedHttpAsyncCacheStorage

      public MemcachedHttpAsyncCacheStorage(net.spy.memcached.MemcachedClient cache)
      Create a storage backend using the pre-configured given memcached client.
      Parameters:
      cache - client to use for communicating with memcached

    • MemcachedHttpAsyncCacheStorage

      public MemcachedHttpAsyncCacheStorage(net.spy.memcached.MemcachedClient client, CacheConfig config, HttpCacheEntrySerializer<byte[]> serializer, KeyHashingScheme keyHashingScheme)
      Create a storage backend using the given memcached client and applying the given cache configuration, serialization, and hashing mechanisms.
      Parameters:
      client - how to talk to memcached
      config - apply HTTP cache-related options
      serializer - alternative serialization mechanism
      keyHashingScheme - how to map higher-level logical "storage keys" onto "cache keys" suitable for use with memcached

  • Method Details