Package org.apache.http.impl.client.cache

Class CachingExec

java.lang.Object

org.apache.http.impl.client.cache.CachingExec

All Implemented Interfaces:

ClientExecChain

@Contract(threading=SAFE_CONDITIONAL)
public class CachingExec
extends java.lang.Object
implements ClientExecChain

Request executor in the request execution chain that is responsible for transparent 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.

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.

Further responsibilities such as communication with the opposite endpoint is delegated to the next executor in the request execution chain.

Since:

4.3

Constructor Summary

Constructors

Constructor	Description
CachingExec(ClientExecChain backend)
CachingExec(ClientExecChain backend, ResourceFactory resourceFactory, HttpCacheStorage storage, CacheConfig config)
CachingExec(ClientExecChain backend, org.apache.http.impl.client.cache.HttpCache cache, CacheConfig config)
CachingExec(ClientExecChain backend, org.apache.http.impl.client.cache.HttpCache cache, CacheConfig config, org.apache.http.impl.client.cache.AsynchronousValidator asynchRevalidator)

Method Summary

Modifier and Type	Method	Description
CloseableHttpResponse	execute(HttpRoute route, HttpRequestWrapper request)
CloseableHttpResponse	execute(HttpRoute route, HttpRequestWrapper request, HttpClientContext context)
CloseableHttpResponse	execute(HttpRoute route, HttpRequestWrapper request, HttpClientContext context, HttpExecutionAware execAware)	Executes th request either by transmitting it to the target server or by passing it onto the next executor in the request execution chain.
long	getCacheHits()	Reports the number of times that the cache successfully responded to an HttpRequest without contacting the origin server.
long	getCacheMisses()	Reports the number of times that the cache contacted the origin server because it had no appropriate response cached.
long	getCacheUpdates()	Reports the number of times that the cache was able to satisfy a response by revalidating an existing but stale cache entry.
boolean	supportsRangeAndContentRangeHeaders()	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

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

Constructor Detail

CachingExec

public CachingExec(ClientExecChain backend,
                   org.apache.http.impl.client.cache.HttpCache cache,
                   CacheConfig config)

CachingExec

public CachingExec(ClientExecChain backend,
                   org.apache.http.impl.client.cache.HttpCache cache,
                   CacheConfig config,
                   org.apache.http.impl.client.cache.AsynchronousValidator asynchRevalidator)

CachingExec

public CachingExec(ClientExecChain backend,
                   ResourceFactory resourceFactory,
                   HttpCacheStorage storage,
                   CacheConfig config)

CachingExec

public CachingExec(ClientExecChain backend)

Method Detail

getCacheHits

public long getCacheHits()

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()

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()

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 CloseableHttpResponse execute(HttpRoute route,
                                     HttpRequestWrapper request)
                              throws java.io.IOException,
                                     HttpException

Throws:

java.io.IOException

HttpException

execute

public CloseableHttpResponse execute(HttpRoute route,
                                     HttpRequestWrapper request,
                                     HttpClientContext context)
                              throws java.io.IOException,
                                     HttpException

Throws:

java.io.IOException

HttpException

execute

public CloseableHttpResponse execute(HttpRoute route,
                                     HttpRequestWrapper request,
                                     HttpClientContext context,
                                     HttpExecutionAware execAware)
                              throws java.io.IOException,
                                     HttpException

Description copied from interface: ClientExecChain

Executes th request either by transmitting it to the target server or by passing it onto the next executor in the request execution chain.

Specified by:

execute in interface ClientExecChain

Parameters:

route - connection route.

request - current request.

context - current HTTP context.

execAware - receiver of notifications of blocking I/O operations.

Returns:

HTTP response either received from the opposite endpoint or generated locally.

Throws:

java.io.IOException - in case of a I/O error. (this type of exceptions are potentially recoverable).

HttpException - in case of an HTTP protocol error (usually this type of exceptions are non-recoverable).

supportsRangeAndContentRangeHeaders

public boolean supportsRangeAndContentRangeHeaders()

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