org.wandora.modules.cache

Interface CacheService

All Superinterfaces:

Module

All Known Implementing Classes:

DiskCacheModule

public interface CacheService
extends Module

An interface for caching services. Pages, which can be any content really, can be stored in the cache using cache keys. The key is just any string that identifies the cached page. The pages are then retrieved using the same keys. In addition, timestamps in milliseconds can be used so that cached pages older than a specified value are not reused.

It is vital that the InputStreams and OutputStreams returned by getPage and storePage be properly closed in all cases, even if exceptions are encountered. Failing to do so may cause the cache to remain in a locked state and other threads be unable to use it.

See CachedAction for an abstract action that can take advantage of caching services.

Author:

olli

Method Summary

Modifier and Type	Method and Description
java.io.InputStream	getPage(java.lang.String key, long modifyTime) Gets a cached version of a page if one exists in the cache.
java.io.OutputStream	storePage(java.lang.String key, long modifyTime) Stores a cached version of a page with the given time stamp.

Methods inherited from interface org.wandora.modules.Module

getDependencies, init, isInitialized, isRunning, start, stop

Method Detail

getPage

java.io.InputStream getPage(java.lang.String key,
                            long modifyTime)

Gets a cached version of a page if one exists in the cache. If modifyTime parameter is greater than 0, the page must be never than the time indicated by the parameter. If a cached version doesn't exist, or it is too old, returns null.

Parameters:

key - The key of the cached page.

modifyTime - The minimum caching time of the page, or 0 if no such limit is used.

Returns:

An input stream from which the stored page can be read. The stream must be properly closed afterwards.

storePage

java.io.OutputStream storePage(java.lang.String key,
                               long modifyTime)

Stores a cached version of a page with the given time stamp.

Parameters:

key - The key of the cached page.

modifyTime - A timestamp for the cached version.

Returns:

An output stream into which the cached version is written. The stream must be properly closed afterwards.