org.riotfamily.cachius
Interface CacheHandler

All Known Implementing Classes:

ControllerCacheHandler, ResponseCapturingHandler, ServletWriterHandler, SessionIdCacheHandler, ZippedResponseHandler

public interface CacheHandler

Callback interface that can be passed to CacheService.handle(CacheHandler).

Since:

8.0

Author:

Felix Gnass [fgnass at neteye dot de]

Field Summary

static long

CACHE_ETERNALLY

Method Summary

String	getCacheKey() Returns the key that is used to look up a previously cached version.
long	getLastModified() Returns the date (as timestamp) when the content was modified for the last time.
long	getTimeToLive() Returns the time in milliseconds that has to be elapsed since the last up-to-date check before another check is performed.
void	handleUncached() Callback method that is invoked when no CacheItem could be created.
boolean	updateCacheItem(CacheItem cacheItem) Callback method that is invoked when no cached version exists or the cached content is not up-to-date.
void	writeCacheItem(CacheItem cacheItem) Callback method that is invoked when an up-to-date CacheItem exists.

Field Detail

CACHE_ETERNALLY

static final long CACHE_ETERNALLY

See Also:

Constant Field Values

Method Detail

getCacheKey

String getCacheKey()

Returns the key that is used to look up a previously cached version. The key must include all values that govern the output. The key itself is not interpreted in any way and thus can have an arbitrary format.

getTimeToLive

long getTimeToLive()

Returns the time in milliseconds that has to be elapsed since the last up-to-date check before another check is performed. Implementors may return CACHE_ETERNALLY to indicate that the content should be cached eternally.

getLastModified

long getLastModified()
                     throws Exception

Returns the date (as timestamp) when the content was modified for the last time. The updateCacheItem(CacheItem) method will not be called unless this date is newer than the timestamp of the cached version.

Throws:

Exception

handleUncached

void handleUncached()
                    throws Exception

Callback method that is invoked when no CacheItem could be created. This can be the case when either getCacheKey() returns null, the cache is disabled or an unexpected error occurred.

Throws:

Exception

updateCacheItem

boolean updateCacheItem(CacheItem cacheItem)
                        throws Exception

Callback method that is invoked when no cached version exists or the cached content is not up-to-date. Implementors must obtain a Writer or an OutputStram by calling CacheItem.getWriter() or CacheItem.getOutputStream() and write their content into it.

Returns:

true if the CacheItem should be updated or false if it should be discarded.

Throws:

Exception

writeCacheItem

void writeCacheItem(CacheItem cacheItem)
                    throws IOException

Callback method that is invoked when an up-to-date CacheItem exists. Implementors must invoke one of the CacheItem.writeTo(...) to write the cached content to its destination.

Throws:

IOException