Class CacheConfig

java.lang.Object
org.apache.hc.client5.http.impl.cache.CacheConfig
All Implemented Interfaces:
Cloneable
public class CacheConfig extends Object implements Cloneable

Configuration for HTTP caches

Cache configuration can be grouped into the following categories:

Protocol options. I some cases the HTTP protocol allows for conditional behaviors or optional protocol extensions. Such conditional protocol behaviors or extensions can be turned on or off here. See isNeverCacheHTTP10ResponsesWithQuery(), isNeverCacheHTTP11ResponsesWithQuery(), isStaleIfErrorEnabled()

Cache size. If the backend storage supports these limits, one can specify the maximum number of cache entries as well as the getMaxObjectSize() maximum cacheable response body size}.

Public/private caching. By default, the caching module considers itself to be a shared (public) cache, and will not, for example, cache responses to requests with Authorization headers or responses marked with Cache-Control: private. If, however, the cache is only going to be used by one logical "user" (behaving similarly to a browser cache), then one may want to isSharedCache() turn off the shared cache setting}.

Heuristic caching. Per HTTP caching specification, a cache may cache certain cache entries even if no explicit cache control headers are set by the origin. This behavior is off by default, but you may want to turn this on if you are working with an origin that doesn't set proper headers but where one may still want to cache the responses. Use isHeuristicCachingEnabled() to enable heuristic caching}, then specify either a default freshness lifetime and/or a fraction of the time since the resource was last modified.

Background validation. The cache module supports the stale-while-revalidate directive, which allows certain cache entry revalidations to happen in the background. Asynchronous validation is enabled by default but it could be disabled by setting the number of re-validation workers to 0 with getAsynchronousWorkers() parameter

  • Field Details

    • DEFAULT_MAX_OBJECT_SIZE_BYTES

      public static final int DEFAULT_MAX_OBJECT_SIZE_BYTES
      Default setting for the maximum object size that will be cached, in bytes.
      See Also:

    • DEFAULT_MAX_CACHE_ENTRIES

      public static final int DEFAULT_MAX_CACHE_ENTRIES
      Default setting for the maximum number of cache entries that will be retained.
      See Also:

    • DEFAULT_MAX_UPDATE_RETRIES

      public static final int DEFAULT_MAX_UPDATE_RETRIES
      Default setting for the number of retries on a failed cache processChallenge
      See Also:

    • DEFAULT_303_CACHING_ENABLED

      @Deprecated public static final boolean DEFAULT_303_CACHING_ENABLED
      Deprecated.
      No longer applicable. Do not use.
      See Also:

    • DEFAULT_WEAK_ETAG_ON_PUTDELETE_ALLOWED

      @Deprecated public static final boolean DEFAULT_WEAK_ETAG_ON_PUTDELETE_ALLOWED
      Deprecated.
      No longer applicable. Do not use.
      See Also:

    • DEFAULT_HEURISTIC_CACHING_ENABLED

      public static final boolean DEFAULT_HEURISTIC_CACHING_ENABLED
      Default setting for heuristic caching
      See Also:

    • DEFAULT_HEURISTIC_COEFFICIENT

      public static final float DEFAULT_HEURISTIC_COEFFICIENT
      Default coefficient used to heuristically determine freshness lifetime from the Last-Modified time of a cache entry.
      See Also:

    • DEFAULT_HEURISTIC_LIFETIME

      public static final org.apache.hc.core5.util.TimeValue DEFAULT_HEURISTIC_LIFETIME
      Default lifetime to be assumed when we cannot calculate freshness heuristically.

    • DEFAULT_ASYNCHRONOUS_WORKERS

      public static final int DEFAULT_ASYNCHRONOUS_WORKERS
      Default number of worker threads to allow for background revalidations resulting from the stale-while-revalidate directive.
      See Also:

    • DEFAULT

      public static final CacheConfig DEFAULT

    • maxObjectSize

      private final long maxObjectSize

    • maxCacheEntries

      private final int maxCacheEntries

    • maxUpdateRetries

      private final int maxUpdateRetries

    • heuristicCachingEnabled

      private final boolean heuristicCachingEnabled

    • heuristicCoefficient

      private final float heuristicCoefficient

    • heuristicDefaultLifetime

      private final org.apache.hc.core5.util.TimeValue heuristicDefaultLifetime

    • sharedCache

      private final boolean sharedCache

    • freshnessCheckEnabled

      private final boolean freshnessCheckEnabled

    • asynchronousWorkers

      private final int asynchronousWorkers

    • neverCacheHTTP10ResponsesWithQuery

      private final boolean neverCacheHTTP10ResponsesWithQuery

    • staleIfErrorEnabled

      private final boolean staleIfErrorEnabled

    • neverCacheHTTP11ResponsesWithQuery

      private final boolean neverCacheHTTP11ResponsesWithQuery
      A constant indicating whether HTTP/1.1 responses with a query string should never be cached.

  • Constructor Details

    • CacheConfig

      CacheConfig(long maxObjectSize, int maxCacheEntries, int maxUpdateRetries, boolean heuristicCachingEnabled, float heuristicCoefficient, org.apache.hc.core5.util.TimeValue heuristicDefaultLifetime, boolean sharedCache, boolean freshnessCheckEnabled, int asynchronousWorkers, boolean neverCacheHTTP10ResponsesWithQuery, boolean neverCacheHTTP11ResponsesWithQuery, boolean staleIfErrorEnabled)

  • Method Details

    • getMaxObjectSize

      public long getMaxObjectSize()
      Returns the current maximum response body size that will be cached.
      Returns:
      size in bytes
      Since:
      4.2

    • isNeverCacheHTTP10ResponsesWithQuery

      public boolean isNeverCacheHTTP10ResponsesWithQuery()
      Returns whether the cache will never cache HTTP 1.0 responses with a query string or not.
      Returns:
      true to not cache query string responses, false to cache if explicit cache headers are found

    • isNeverCacheHTTP11ResponsesWithQuery

      public boolean isNeverCacheHTTP11ResponsesWithQuery()
      Determines whether HTTP/1.1 responses with query strings should never be cached by the client. By default, caching of such responses is allowed. Enabling this option may improve security by preventing responses with sensitive information from being cached.

      Note that this option only applies to HTTP/1.1.

      Returns:
      true if HTTP/1.1 responses with query strings should never be cached; false otherwise.
      Since:
      5.4

    • isStaleIfErrorEnabled

      public boolean isStaleIfErrorEnabled()
      Returns a boolean value indicating whether the stale-if-error cache directive is enabled. If this option is enabled, cached responses that have become stale due to an error (such as a server error or a network failure) will be returned instead of generating a new request. This can help to reduce the load on the origin server and improve performance.
      Returns:
      true if the stale-if-error directive is enabled, or false otherwise.

    • getMaxCacheEntries

      public int getMaxCacheEntries()
      Returns the maximum number of cache entries the cache will retain.

    • getMaxUpdateRetries

      public int getMaxUpdateRetries()
      Returns the number of times to retry a cache processChallenge on failure

    • is303CachingEnabled

      @Deprecated public boolean is303CachingEnabled()
      Deprecated.
      No longer applicable. Do not use.

    • isWeakETagOnPutDeleteAllowed

      @Deprecated public boolean isWeakETagOnPutDeleteAllowed()
      Deprecated.
      Do not use.
      Returns whether weak etags is allowed with PUT/DELETE methods.
      Returns:
      true if it is allowed.

    • isHeuristicCachingEnabled

      public boolean isHeuristicCachingEnabled()
      Returns whether heuristic caching is enabled.
      Returns:
      true if it is enabled.

    • getHeuristicCoefficient

      public float getHeuristicCoefficient()
      Returns lifetime coefficient used in heuristic freshness caching.

    • getHeuristicDefaultLifetime

      public org.apache.hc.core5.util.TimeValue getHeuristicDefaultLifetime()
      Get the default lifetime to be used if heuristic freshness calculation is not possible.

    • isSharedCache

      public boolean isSharedCache()
      Returns whether the cache will behave as a shared cache or not.
      Returns:
      true for a shared cache, false for a non- shared (private) cache

    • isFreshnessCheckEnabled

      public boolean isFreshnessCheckEnabled()
      Returns whether the cache will perform an extra cache entry freshness check upon cache update in case of a cache miss
      Since:
      5.0

    • getAsynchronousWorkers

      public int getAsynchronousWorkers()
      Returns the maximum number of threads to allow for background revalidations due to the stale-while-revalidate directive. A value of 0 means background revalidations are disabled.

    • clone

      protected CacheConfig clone() throws CloneNotSupportedException
      Overrides:
      clone in class Object
      Throws:
      CloneNotSupportedException

    • custom

      public static CacheConfig.Builder custom()

    • copy

      public static CacheConfig.Builder copy(CacheConfig config)

    • toString

      public String toString()
      Overrides:
      toString in class Object