public class

MemcachedHttpCacheStorage

extends Object
implements HttpCacheStorage
java.lang.Object
   ↳ org.apache.http.impl.client.cache.memcached.MemcachedHttpCacheStorage

Class Overview

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, effectively providing cache peering of a sort
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).

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.

Summary

Public Constructors
MemcachedHttpCacheStorage(InetSocketAddress address)
Create a storage backend talking to a memcached instance listening on the specified host and port.
MemcachedHttpCacheStorage(MemcachedClientIF cache)
Create a storage backend using the pre-configured given memcached client.
MemcachedHttpCacheStorage(MemcachedClientIF client, CacheConfig config, HttpCacheEntrySerializer serializer)
Create a storage backend using the given memcached client and applying the given cache configuration and cache entry serialization mechanism.
Public Methods
HttpCacheEntry getEntry(String url)
Retrieves the cache entry stored under the given key or null if no entry exists under that key.
void putEntry(String url, HttpCacheEntry entry)
Store a given cache entry under the given key.
void removeEntry(String url)
Deletes/invalidates/removes any cache entries currently stored under the given key.
void updateEntry(String url, HttpCacheUpdateCallback callback)
Atomically applies the given callback to update an existing cache entry under a given key.
[Expand]
Inherited Methods
From class java.lang.Object
From interface org.apache.http.client.cache.HttpCacheStorage

Public Constructors

public MemcachedHttpCacheStorage (InetSocketAddress address)

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

public MemcachedHttpCacheStorage (MemcachedClientIF cache)

Create a storage backend using the pre-configured given memcached client.

Parameters
cache client to use for communicating with memcached

public MemcachedHttpCacheStorage (MemcachedClientIF client, CacheConfig config, HttpCacheEntrySerializer serializer)

Create a storage backend using the given memcached client and applying the given cache configuration and cache entry serialization mechanism.

Parameters
client how to talk to memcached
config apply HTTP cache-related options
serializer how to serialize the cache entries before writing them out to memcached. The provided DefaultHttpCacheEntrySerializer is a fine serialization mechanism to use here.

Public Methods

public HttpCacheEntry getEntry (String url)

Retrieves the cache entry stored under the given key or null if no entry exists under that key.

Parameters
url cache key
Returns
Throws
IOException

public void putEntry (String url, HttpCacheEntry entry)

Store a given cache entry under the given key.

Parameters
url where in the cache to store the entry
entry cached response to store
Throws
IOException

public void removeEntry (String url)

Deletes/invalidates/removes any cache entries currently stored under the given key.

Throws
IOException

public void updateEntry (String url, HttpCacheUpdateCallback callback)

Atomically applies the given callback to update an existing cache entry under a given key.

Parameters
url indicates which entry to modify
callback performs the update; see HttpCacheUpdateCallback for details, but roughly the callback expects to be handed the current entry and will return the new value for the entry.
Throws
HttpCacheUpdateException
IOException