CacheConfig (Apache HttpClient Cache 5.4.1 API)

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

Nested Class Summary

Nested Classes
Modifier and Type Class and Description

static class CacheConfig.Builder

Nested Classes
Modifier and Type	Class and Description
`static class`	`CacheConfig.Builder`

Field Summary

Fields
Modifier and Type	Field and Description
`static CacheConfig`	`DEFAULT`
`static boolean`	`DEFAULT_303_CACHING_ENABLED` Deprecated. No longer applicable. Do not use.
`static int`	`DEFAULT_ASYNCHRONOUS_WORKERS` Default number of worker threads to allow for background revalidations resulting from the stale-while-revalidate directive.
`static boolean`	`DEFAULT_HEURISTIC_CACHING_ENABLED` Default setting for heuristic caching
`static float`	`DEFAULT_HEURISTIC_COEFFICIENT` Default coefficient used to heuristically determine freshness lifetime from the Last-Modified time of a cache entry.
`static org.apache.hc.core5.util.TimeValue`	`DEFAULT_HEURISTIC_LIFETIME` Default lifetime to be assumed when we cannot calculate freshness heuristically.
`static int`	`DEFAULT_MAX_CACHE_ENTRIES` Default setting for the maximum number of cache entries that will be retained.
`static int`	`DEFAULT_MAX_OBJECT_SIZE_BYTES` Default setting for the maximum object size that will be cached, in bytes.
`static int`	`DEFAULT_MAX_UPDATE_RETRIES` Default setting for the number of retries on a failed cache processChallenge
`static boolean`	`DEFAULT_WEAK_ETAG_ON_PUTDELETE_ALLOWED` Deprecated. No longer applicable. Do not use.

Method Summary

All Methods Static Methods Instance Methods Concrete Methods Deprecated Methods
Modifier and Type	Method and Description
`protected CacheConfig`	`clone()`
`static CacheConfig.Builder`	`copy(CacheConfig config)`
`static CacheConfig.Builder`	`custom()`
`int`	`getAsynchronousWorkers()` Returns the maximum number of threads to allow for background revalidations due to the `stale-while-revalidate` directive.
`float`	`getHeuristicCoefficient()` Returns lifetime coefficient used in heuristic freshness caching.
`org.apache.hc.core5.util.TimeValue`	`getHeuristicDefaultLifetime()` Get the default lifetime to be used if heuristic freshness calculation is not possible.
`int`	`getMaxCacheEntries()` Returns the maximum number of cache entries the cache will retain.
`long`	`getMaxObjectSize()` Returns the current maximum response body size that will be cached.
`int`	`getMaxUpdateRetries()` Returns the number of times to retry a cache processChallenge on failure
`boolean`	`is303CachingEnabled()` Deprecated. No longer applicable. Do not use.
`boolean`	`isFreshnessCheckEnabled()` Returns whether the cache will perform an extra cache entry freshness check upon cache update in case of a cache miss
`boolean`	`isHeuristicCachingEnabled()` Returns whether heuristic caching is enabled.
`boolean`	`isNeverCacheHTTP10ResponsesWithQuery()` Returns whether the cache will never cache HTTP 1.0 responses with a query string or not.
`boolean`	`isNeverCacheHTTP11ResponsesWithQuery()` Determines whether HTTP/1.1 responses with query strings should never be cached by the client.
`boolean`	`isSharedCache()` Returns whether the cache will behave as a shared cache or not.
`boolean`	`isStaleIfErrorEnabled()` Returns a boolean value indicating whether the stale-if-error cache directive is enabled.
`boolean`	`isWeakETagOnPutDeleteAllowed()` Deprecated. Do not use.
`String`	`toString()`

Methods inherited from class java.lang.Object
equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

- Field Detail
  - 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:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - DEFAULT_303_CACHING_ENABLED
```
@Deprecated
public static final boolean DEFAULT_303_CACHING_ENABLED
```
    Deprecated. No longer applicable. Do not use.
    
    See Also:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - DEFAULT_HEURISTIC_CACHING_ENABLED
```
public static final boolean DEFAULT_HEURISTIC_CACHING_ENABLED
```
    Default setting for heuristic caching
    
    See Also:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - 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:
    
    Constant Field Values
  - DEFAULT
```
public static final CacheConfig DEFAULT
```
- Method Detail
  - 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

Class CacheConfig

Nested Class Summary

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

DEFAULT_MAX_OBJECT_SIZE_BYTES

DEFAULT_MAX_CACHE_ENTRIES

DEFAULT_MAX_UPDATE_RETRIES

DEFAULT_303_CACHING_ENABLED

DEFAULT_WEAK_ETAG_ON_PUTDELETE_ALLOWED

DEFAULT_HEURISTIC_CACHING_ENABLED

DEFAULT_HEURISTIC_COEFFICIENT

DEFAULT_HEURISTIC_LIFETIME

DEFAULT_ASYNCHRONOUS_WORKERS

DEFAULT

Method Detail

getMaxObjectSize

isNeverCacheHTTP10ResponsesWithQuery

isNeverCacheHTTP11ResponsesWithQuery

isStaleIfErrorEnabled

getMaxCacheEntries

getMaxUpdateRetries

is303CachingEnabled

isWeakETagOnPutDeleteAllowed

isHeuristicCachingEnabled

getHeuristicCoefficient

getHeuristicDefaultLifetime

isSharedCache

isFreshnessCheckEnabled

getAsynchronousWorkers

clone

custom

copy

toString