cache (Sun Java System Application Server Platform Edition 8.1 2005Q2 Update 2 Developer's Guide)

Sun Java System Application Server Platform Edition 8.1 2005Q2 Update 2 Developer's Guide

cache

Configures caching for web application components.

sun-web-app (sun-web.xml)

The following table describes subelements for the cache element.

Table A–9 cache Subelements


Element	Required	Description
cache-helper	zero or more	Specifies a custom class that implements the `CacheHelper` interface.
default-helper	zero or one	Allows you to change the properties of the default, built-in cache-helper class.
property (with attributes)	zero or more	Specifies a cache property, which has a name and a value.
cache-mapping	zero or more	Maps a URL pattern or a servlet name to its cacheability constraints.

The following table describes attributes for the cache element.

Table A–10 cache Attributes


Attribute	Default	Description
`max-entries`	`4096`	(optional) Specifies the maximum number of entries the cache can contain. Must be a positive integer.
`timeout-in-seconds`	`30`	(optional) Specifies the maximum amount of time in seconds that an entry can remain in the cache after it is created or refreshed. Can be overridden by a timeout element.
`enabled`	`true`	(optional) Determines whether servlet and JSP caching is enabled.

The following table describes properties for the cache element.

Table A–11 cache Properties


Property	Default	Description
`cacheClassName`	`com.sun.appserv.web.cache.LruCache`	Specifies the fully qualified name of the class that implements the cache functionality. See Cache Class Names for possible values.
`MultiLRUSegmentSize`	`4096`	Specifies the number of entries in a segment of the cache table that should have its own LRU (least recently used) list. Applicable only if `cacheClassName` is set to `com.sun.appserv.web.cache.MultiLruCache`.
`MaxSize`	unlimited; `Long.MAX_VALUE`	Specifies an upper bound on the cache memory size in bytes (KB or MB units). Example values are `32 KB` or `2 MB`. Applicable only if `cacheClassName` is set to `com.sun.appserv.web.cache.BoundedMultiLruCache`.

The following table lists possible values of the cacheClassName property.

Table A–12 cacheClassName Values


Value	Description
`com.sun.appserv.web.cache.LruCache`	A bounded cache with an LRU (least recently used) cache replacement policy.
`com.sun.appserv.web.cache.BaseCache`	An unbounded cache suitable if the maximum number of entries is known.
`com.sun.appserv.web.cache.MultiLruCache`	A cache suitable for a large number of entries (>4096). Uses the `MultiLRUSegmentSize` property.
`com.sun.appserv.web.cache.BoundedMultiLruCache`	A cache suitable for limiting the cache size by memory rather than number of entries. Uses the `MaxSize` property.