java.lang.Object
- com.twelvemonkeys.servlet.cache.HTTPCache

```
public class HTTPCache
extends java.lang.Object
```
A "simple" HTTP cache. - Use a mix of parameters and hashcode + lenght with fixed (max) lenght? (Hashcodes of Strings are constant). - Store full filenames in .vary, instead of just extension, and use short filenames? (and only one .vary per dir).

Version:

$Id: HTTPCache.java#4 $

Author:

Harald Kuhr

Field Summary

Fields
Modifier and Type	Field	Description
`protected static java.lang.String`	`FILE_EXT_HEADERS`	The file extension for header files (`".headers"`)
`protected static java.lang.String`	`FILE_EXT_VARY`	The file extension for varation-info files (`".vary"`)
`protected static java.lang.String`	`HEADER_CACHE_CONTROL`	The HTTP header `"Cache-Control"`
`protected static java.lang.String`	`HEADER_CACHED_TIME`	HTTP extension header `"X-Cached-At"`
`protected static java.lang.String`	`HEADER_CONTENT_TYPE`	The HTTP header `"Content-Type"`
`protected static java.lang.String`	`HEADER_DATE`	The HTTP header `"Date"`
`protected static java.lang.String`	`HEADER_ETAG`	The HTTP header `"ETag"`
`protected static java.lang.String`	`HEADER_EXPIRES`	The HTTP header `"Expires"`
`protected static java.lang.String`	`HEADER_IF_MODIFIED_SINCE`	The HTTP header `"If-Modified-Since"`
`protected static java.lang.String`	`HEADER_IF_NONE_MATCH`	The HTTP header `"If-None-Match"`
`protected static java.lang.String`	`HEADER_LAST_MODIFIED`	The HTTP header `"Last-Modified"`
`protected static java.lang.String`	`HEADER_PRAGMA`	The HTTP header `"Pragma"`
`protected static java.lang.String`	`HEADER_VARY`	The HTTP header `"Vary"`
`protected static java.lang.String`	`HEADER_WARNING`	The HTTP header `"Warning"`

Constructor Summary

Constructors
Modifier	Constructor	Description
	`HTTPCache(java.io.File pTempFolder, long pDefaultCacheExpiryTime, int pMaxMemCacheSize, int pMaxCachedEntites, boolean pDeleteCacheOnExit)`	Creates an `HTTPCache`.
`protected`	`HTTPCache(java.io.File pTempFolder, long pDefaultCacheExpiryTime, int pMaxMemCacheSize, int pMaxCachedEntites, boolean pDeleteCacheOnExit, java.util.logging.Logger pLogger)`
	`HTTPCache(java.lang.String pName, javax.servlet.ServletContext pContext, int pDefaultCacheExpiryTime, int pMaxMemCacheSize, int pMaxCachedEntites, boolean pDeleteCacheOnExit)`	Deprecated. Use `HTTPCache(File, long, int, int, boolean)` instead.

Method Summary

All Methods Instance Methods Concrete Methods
Modifier and Type	Method	Description
`void`	`doCached(CacheRequest pRequest, CacheResponse pResponse, ResponseResolver pResolver)`	Looks up the `CachedEntity` for the given request.
`protected java.io.File`	`getRealFile(CacheRequest pRequest)`	Allows a server-side cache mechanism to peek at the real file.
`protected void`	`invalidate(CacheRequest pRequest)`
`java.lang.String`	`toString()`

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

- Field Detail
  - HEADER_CACHE_CONTROL
```
protected static final java.lang.String HEADER_CACHE_CONTROL
```
    The HTTP header "Cache-Control"
    
    See Also:
    
    Constant Field Values
  - HEADER_CONTENT_TYPE
```
protected static final java.lang.String HEADER_CONTENT_TYPE
```
    The HTTP header "Content-Type"
    
    See Also:
    
    Constant Field Values
  - HEADER_DATE
```
protected static final java.lang.String HEADER_DATE
```
    The HTTP header "Date"
    
    See Also:
    
    Constant Field Values
  - HEADER_ETAG
```
protected static final java.lang.String HEADER_ETAG
```
    The HTTP header "ETag"
    
    See Also:
    
    Constant Field Values
  - HEADER_EXPIRES
```
protected static final java.lang.String HEADER_EXPIRES
```
    The HTTP header "Expires"
    
    See Also:
    
    Constant Field Values
  - HEADER_IF_MODIFIED_SINCE
```
protected static final java.lang.String HEADER_IF_MODIFIED_SINCE
```
    The HTTP header "If-Modified-Since"
    
    See Also:
    
    Constant Field Values
  - HEADER_IF_NONE_MATCH
```
protected static final java.lang.String HEADER_IF_NONE_MATCH
```
    The HTTP header "If-None-Match"
    
    See Also:
    
    Constant Field Values
  - HEADER_LAST_MODIFIED
```
protected static final java.lang.String HEADER_LAST_MODIFIED
```
    The HTTP header "Last-Modified"
    
    See Also:
    
    Constant Field Values
  - HEADER_PRAGMA
```
protected static final java.lang.String HEADER_PRAGMA
```
    The HTTP header "Pragma"
    
    See Also:
    
    Constant Field Values
  - HEADER_VARY
```
protected static final java.lang.String HEADER_VARY
```
    The HTTP header "Vary"
    
    See Also:
    
    Constant Field Values
  - HEADER_WARNING
```
protected static final java.lang.String HEADER_WARNING
```
    The HTTP header "Warning"
    
    See Also:
    
    Constant Field Values
  - HEADER_CACHED_TIME
```
protected static final java.lang.String HEADER_CACHED_TIME
```
    HTTP extension header "X-Cached-At"
    
    See Also:
    
    Constant Field Values
  - FILE_EXT_HEADERS
```
protected static final java.lang.String FILE_EXT_HEADERS
```
    The file extension for header files (".headers")
    
    See Also:
    
    Constant Field Values
  - FILE_EXT_VARY
```
protected static final java.lang.String FILE_EXT_VARY
```
    The file extension for varation-info files (".vary")
    
    See Also:
    
    Constant Field Values
- Constructor Detail
  - HTTPCache
```
protected HTTPCache(java.io.File pTempFolder,
                    long pDefaultCacheExpiryTime,
                    int pMaxMemCacheSize,
                    int pMaxCachedEntites,
                    boolean pDeleteCacheOnExit,
                    java.util.logging.Logger pLogger)
```
  - HTTPCache
```
public HTTPCache(java.io.File pTempFolder,
                 long pDefaultCacheExpiryTime,
                 int pMaxMemCacheSize,
                 int pMaxCachedEntites,
                 boolean pDeleteCacheOnExit)
```
    Creates an HTTPCache.
    
    Parameters:
    
    pTempFolder - the temp folder for this cache.
    
    pDefaultCacheExpiryTime - Default expiry time for cached entities, >= 0
    
    pMaxMemCacheSize - Maximum size of in-memory cache for content in bytes, >= 0 (0 means no in-memory cache)
    
    pMaxCachedEntites - Maximum number of entities in cache
    
    pDeleteCacheOnExit - specifies wether the file cache should be deleted when the application or VM shuts down
    
    Throws:
    
    java.lang.IllegalArgumentException - if pName or pContext is null or if any of pDefaultCacheExpiryTime, pMaxMemCacheSize or pMaxCachedEntites are negative, or if the directory as given in the context attribute "javax.servlet.context.tempdir" does not exist, and cannot be created.
  - HTTPCache
```
public HTTPCache(java.lang.String pName,
                 javax.servlet.ServletContext pContext,
                 int pDefaultCacheExpiryTime,
                 int pMaxMemCacheSize,
                 int pMaxCachedEntites,
                 boolean pDeleteCacheOnExit)
```
    Deprecated.
    Use HTTPCache(File, long, int, int, boolean) instead.
    
    Creates an HTTPCache.
    
    Parameters:
    
    pName - Name of this cache (should be unique per application). Used for temp folder
    
    pContext - Servlet context for the application.
    
    pDefaultCacheExpiryTime - Default expiry time for cached entities, >= 0
    
    pMaxMemCacheSize - Maximum size of in-memory cache for content in bytes, >= 0 (0 means no in-memory cache)
    
    pMaxCachedEntites - Maximum number of entities in cache
    
    pDeleteCacheOnExit - specifies wether the file cache should be deleted when the application or VM shuts down
    
    Throws:
    
    java.lang.IllegalArgumentException - if pName or pContext is null or if any of pDefaultCacheExpiryTime, pMaxMemCacheSize or pMaxCachedEntites are negative, or if the directory as given in the context attribute "javax.servlet.context.tempdir" does not exist, and cannot be created.
- Method Detail
  - toString
```
public java.lang.String toString()
```
    Overrides:
    
    toString in class java.lang.Object
  - doCached
```
public void doCached(CacheRequest pRequest,
                     CacheResponse pResponse,
                     ResponseResolver pResolver)
              throws java.io.IOException,
                     CacheException
```
    Looks up the CachedEntity for the given request.
    
    Parameters:
    
    pRequest - the request
    
    pResponse - the response
    
    pResolver - the resolver
    
    Throws:
    
    java.io.IOException - if an I/O error occurs
    
    CacheException - if the cached entity can't be resolved for some reason
  - invalidate
```
protected void invalidate(CacheRequest pRequest)
```
  - getRealFile
```
protected java.io.File getRealFile(CacheRequest pRequest)
```
    Allows a server-side cache mechanism to peek at the real file. Default implementation return null.
    
    Parameters:
    
    pRequest - the request
    
    Returns:
    
    null, always

Class HTTPCache

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

HEADER_CACHE_CONTROL

HEADER_CONTENT_TYPE

HEADER_DATE

HEADER_ETAG

HEADER_EXPIRES

HEADER_IF_MODIFIED_SINCE

HEADER_IF_NONE_MATCH

HEADER_LAST_MODIFIED

HEADER_PRAGMA

HEADER_VARY

HEADER_WARNING

HEADER_CACHED_TIME

FILE_EXT_HEADERS

FILE_EXT_VARY

Constructor Detail

HTTPCache

HTTPCache

HTTPCache

Method Detail

toString

doCached

invalidate

getRealFile