org.apache.http.impl.client.cache

Class CachingHttpClient

java.lang.Object

org.apache.http.impl.client.cache.CachingHttpClient

All Implemented Interfaces:

HttpClient

Deprecated.

(4.3) use CachingHttpClientBuilder or CachingHttpClients.

@Deprecated
@ThreadSafe
public class CachingHttpClient
extends Object
implements HttpClient

The CachingHttpClient is meant to be a drop-in replacement for a DefaultHttpClient that transparently adds client-side caching. The current implementation is conditionally compliant with HTTP/1.1 (meaning all the MUST and MUST NOTs are obeyed), although quite a lot, though not all, of the SHOULDs and SHOULD NOTs are obeyed too. Generally speaking, you construct a CachingHttpClient by providing a "backend" HttpClient used for making actual network requests and provide an HttpCacheStorage instance to use for holding onto cached responses. Additional configuration options can be provided by passing in a CacheConfig. Note that all of the usual client related configuration you want to do vis-a-vis timeouts and connection pools should be done on this backend client before constructing a CachingHttpClient from it.

Generally speaking, the CachingHttpClient is implemented as a Decorator of the backend client; for any incoming request it attempts to satisfy it from the cache, but if it can't, or if it needs to revalidate a stale cache entry, it will use the backend client to make an actual request. However, a proper HTTP/1.1 cache won't change the semantics of a request and response; in particular, if you issue an unconditional request you will get a full response (although it may be served to you from the cache, or the cache may make a conditional request on your behalf to the origin). This notion of "semantic transparency" means you should be able to drop a CachingHttpClient into an existing application without breaking anything.

Folks that would like to experiment with alternative storage backends should look at the HttpCacheStorage interface and the related package documentation there. You may also be interested in the provided EhCache and memcached storage backends.

Since:

4.1

Field Summary

Fields

Modifier and Type	Field and Description
static String	CACHE_RESPONSE_STATUS Deprecated. This is the name under which the CacheResponseStatus of a request (for example, whether it resulted in a cache hit) will be recorded if an HttpContext is provided during execution.

Constructor Summary

Constructors

Constructor and Description
CachingHttpClient() Deprecated. Constructs a CachingHttpClient with default caching settings that stores cache entries in memory and uses a vanilla DefaultHttpClient for backend requests.
CachingHttpClient(CacheConfig config) Deprecated. Constructs a CachingHttpClient with the given caching options that stores cache entries in memory and uses a vanilla DefaultHttpClient for backend requests.
CachingHttpClient(HttpClient client) Deprecated. Constructs a CachingHttpClient with default caching settings that stores cache entries in memory and uses the given HttpClient for backend requests.
CachingHttpClient(HttpClient client, CacheConfig config) Deprecated. Constructs a CachingHttpClient with the given caching options that stores cache entries in memory and uses the given HttpClient for backend requests.
CachingHttpClient(HttpClient client, HttpCacheStorage storage, CacheConfig config) Deprecated. Constructs a CachingHttpClient with the given caching options that stores cache entries in the provided storage backend and uses the given HttpClient for backend requests.
CachingHttpClient(HttpClient client, ResourceFactory resourceFactory, HttpCacheStorage storage, CacheConfig config) Deprecated. Constructs a CachingHttpClient with the given caching options that stores cache entries in the provided storage backend and uses the given HttpClient for backend requests.

Method Summary

Methods

Modifier and Type	Method and Description
HttpResponse	execute(HttpHost target, HttpRequest request) Deprecated.
HttpResponse	execute(HttpHost target, HttpRequest originalRequest, HttpContext context) Deprecated.
<T> T	execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler) Deprecated.
<T> T	execute(HttpHost target, HttpRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context) Deprecated.
HttpResponse	execute(HttpUriRequest request) Deprecated.
HttpResponse	execute(HttpUriRequest request, HttpContext context) Deprecated.
<T> T	execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler) Deprecated.
<T> T	execute(HttpUriRequest request, ResponseHandler<? extends T> responseHandler, HttpContext context) Deprecated.
long	getCacheHits() Deprecated. Reports the number of times that the cache successfully responded to an HttpRequest without contacting the origin server.
long	getCacheMisses() Deprecated. Reports the number of times that the cache contacted the origin server because it had no appropriate response cached.
long	getCacheUpdates() Deprecated. Reports the number of times that the cache was able to satisfy a response by revalidating an existing but stale cache entry.
ClientConnectionManager	getConnectionManager() Deprecated.
HttpParams	getParams() Deprecated.
boolean	isSharedCache() Deprecated. Reports whether this CachingHttpClient is configured as a shared (public) or non-shared (private) cache.
boolean	supportsRangeAndContentRangeHeaders() Deprecated. Reports whether this CachingHttpClient implementation supports byte-range requests as specified by the Range and Content-Range headers.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

CACHE_RESPONSE_STATUS

public static final String CACHE_RESPONSE_STATUS

Deprecated.

This is the name under which the CacheResponseStatus of a request (for example, whether it resulted in a cache hit) will be recorded if an HttpContext is provided during execution.

See Also:

Constant Field Values

Constructor Detail

CachingHttpClient

public CachingHttpClient()

Deprecated.

Constructs a CachingHttpClient with default caching settings that stores cache entries in memory and uses a vanilla DefaultHttpClient for backend requests.

CachingHttpClient

public CachingHttpClient(CacheConfig config)

Deprecated.

Constructs a CachingHttpClient with the given caching options that stores cache entries in memory and uses a vanilla DefaultHttpClient for backend requests.

Parameters:

config - cache module options

CachingHttpClient

public CachingHttpClient(HttpClient client)

Deprecated.

Constructs a CachingHttpClient with default caching settings that stores cache entries in memory and uses the given HttpClient for backend requests.

Parameters:

client - used to make origin requests

CachingHttpClient

public CachingHttpClient(HttpClient client,
                 CacheConfig config)

Deprecated.

Constructs a CachingHttpClient with the given caching options that stores cache entries in memory and uses the given HttpClient for backend requests.

Parameters:

config - cache module options

client - used to make origin requests

CachingHttpClient

public CachingHttpClient(HttpClient client,
                 ResourceFactory resourceFactory,
                 HttpCacheStorage storage,
                 CacheConfig config)

Deprecated.

Constructs a CachingHttpClient with the given caching options that stores cache entries in the provided storage backend and uses the given HttpClient for backend requests. However, cached response bodies are managed using the given ResourceFactory.

Parameters:

client - used to make origin requests

resourceFactory - how to manage cached response bodies

storage - where to store cache entries

config - cache module options

CachingHttpClient

public CachingHttpClient(HttpClient client,
                 HttpCacheStorage storage,
                 CacheConfig config)

Deprecated.

Constructs a CachingHttpClient with the given caching options that stores cache entries in the provided storage backend and uses the given HttpClient for backend requests.

Parameters:

client - used to make origin requests

storage - where to store cache entries

config - cache module options

Method Detail

getCacheHits

public long getCacheHits()

Deprecated.

Reports the number of times that the cache successfully responded to an HttpRequest without contacting the origin server.

Returns:

the number of cache hits

getCacheMisses

public long getCacheMisses()

Deprecated.

Reports the number of times that the cache contacted the origin server because it had no appropriate response cached.

Returns:

the number of cache misses

getCacheUpdates

public long getCacheUpdates()

Deprecated.

Reports the number of times that the cache was able to satisfy a response by revalidating an existing but stale cache entry.

Returns:

the number of cache revalidations

execute

public HttpResponse execute(HttpHost target,
                   HttpRequest request)
                     throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public <T> T execute(HttpHost target,
            HttpRequest request,
            ResponseHandler<? extends T> responseHandler)
          throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public <T> T execute(HttpHost target,
            HttpRequest request,
            ResponseHandler<? extends T> responseHandler,
            HttpContext context)
          throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public HttpResponse execute(HttpUriRequest request)
                     throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public HttpResponse execute(HttpUriRequest request,
                   HttpContext context)
                     throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public <T> T execute(HttpUriRequest request,
            ResponseHandler<? extends T> responseHandler)
          throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

execute

public <T> T execute(HttpUriRequest request,
            ResponseHandler<? extends T> responseHandler,
            HttpContext context)
          throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

getConnectionManager

public ClientConnectionManager getConnectionManager()

Deprecated.

Specified by:

getConnectionManager in interface HttpClient

getParams

public HttpParams getParams()

Deprecated.

Specified by:

getParams in interface HttpClient

execute

public HttpResponse execute(HttpHost target,
                   HttpRequest originalRequest,
                   HttpContext context)
                     throws IOException

Deprecated.

Specified by:

execute in interface HttpClient

Throws:

IOException

supportsRangeAndContentRangeHeaders

public boolean supportsRangeAndContentRangeHeaders()

Deprecated.

Reports whether this CachingHttpClient implementation supports byte-range requests as specified by the Range and Content-Range headers.

Returns:

true if byte-range requests are supported

isSharedCache

public boolean isSharedCache()

Deprecated.

Reports whether this CachingHttpClient is configured as a shared (public) or non-shared (private) cache. See CacheConfig.setSharedCache(boolean).

Returns:

true if we are behaving as a shared (public) cache