Class ResponseCache
- java.lang.Object
-
- java.net.ResponseCache
public abstract class ResponseCache extends Object
Represents implementations of URLConnection caches. An instance of such a class can be registered with the system by doing ResponseCache.setDefault(ResponseCache), and the system will call this object in order to:
- store resource data which has been retrieved from an external source into the cache
- try to fetch a requested resource that may have been stored in the cache
- Since:
- 1.5
Constructor Summary
Constructor | Description |
---|---|
ResponseCache() |
Method Summary
Modifier and Type | Method | Description |
---|---|---|
abstract CacheResponse | get(URI uri,
String rqstMethod,
Map<String,List<String>> rqstHeaders) | Retrieve the cached response based on the requesting uri, request method and request headers. |
static ResponseCache | getDefault() | Gets the system-wide response cache. |
abstract CacheRequest | put(URI uri,
URLConnection conn) | The protocol handler calls this method after a resource has been retrieved, and the ResponseCache must decide whether or not to store the resource in its cache. |
static void | setDefault(ResponseCache responseCache) | Sets (or unsets) the system-wide cache. |
Methods declared in class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
Constructor Detail
ResponseCache
public ResponseCache()
Method Detail
getDefault
public static ResponseCache getDefault()
Gets the system-wide response cache.
- Returns:
- the system-wide
ResponseCache
- Throws:
-
SecurityException
- If a security manager has been installed and it deniesNetPermission
("getResponseCache")
- Since:
- 1.5
- See Also:
setDefault(ResponseCache)
setDefault
public static void setDefault(ResponseCache responseCache)
Sets (or unsets) the system-wide cache. Note: non-standard procotol handlers may ignore this setting.
- Parameters:
-
responseCache
- The response cache, ornull
to unset the cache. - Throws:
-
SecurityException
- If a security manager has been installed and it deniesNetPermission
("setResponseCache")
- Since:
- 1.5
- See Also:
getDefault()
get
public abstract CacheResponse get(URI uri, String rqstMethod, Map<String,List<String>> rqstHeaders) throws IOException
Retrieve the cached response based on the requesting uri, request method and request headers. Typically this method is called by the protocol handler before it sends out the request to get the network resource. If a cached response is returned, that resource is used instead.
- Parameters:
-
uri
- aURI
used to reference the requested network resource -
rqstMethod
- aString
representing the request method -
rqstHeaders
- - a Map from request header field names to lists of field values representing the current request headers - Returns:
- a
CacheResponse
instance if available from cache, or null otherwise - Throws:
-
IOException
- if an I/O error occurs -
IllegalArgumentException
- if any one of the arguments is null - See Also:
-
URLConnection.setUseCaches(boolean)
,URLConnection.getUseCaches()
,URLConnection.setDefaultUseCaches(boolean)
,URLConnection.getDefaultUseCaches()
put
public abstract CacheRequest put(URI uri, URLConnection conn) throws IOException
The protocol handler calls this method after a resource has been retrieved, and the ResponseCache must decide whether or not to store the resource in its cache. If the resource is to be cached, then put() must return a CacheRequest object which contains an OutputStream that the protocol handler will use to write the resource into the cache. If the resource is not to be cached, then put must return null.
- Parameters:
-
uri
- aURI
used to reference the requested network resource -
conn
- - a URLConnection instance that is used to fetch the response to be cached - Returns:
- a
CacheRequest
for recording the response to be cached. Null return indicates that the caller does not intend to cache the response. - Throws:
-
IOException
- if an I/O error occurs -
IllegalArgumentException
- if any one of the arguments is null