| <?xml version="1.0"?> |
| |
| <document> |
| <properties> |
| <title>Element Attribute Configuration</title> |
| <author email="ASmuts@apache.org">Aaron Smuts</author> |
| </properties> |
| |
| <body> |
| <section name="Element Attribute Configuration"> |
| <p> |
| The following document describes the various |
| configuration options available for cache elements. |
| Each element put into the cache can be configured |
| independently. You can define element behavior in |
| three ways: as a default setting, as a region setting, |
| or at the element level. |
| </p> |
| |
| <subsection name="Setting the defaults"> |
| <p> |
| The configuration below can be put in the cache.ccf |
| configuration file. It establishes the default behavior |
| for all regions. A region can override these defaults and |
| an individual element can overide these defaults and |
| the region settings. |
| </p> |
| <source><![CDATA[ |
| # DEFAULT CACHE REGION |
| |
| jcs.default=DC |
| jcs.default.cacheattributes= |
| org.apache.jcs.engine.CompositeCacheAttributes |
| jcs.default.cacheattributes.MaxObjects=1000 |
| jcs.default.cacheattributes.MemoryCacheName= |
| org.apache.jcs.engine.memory.lru.LRUMemoryCache |
| jcs.default.cacheattributes.UseMemoryShrinker=true |
| jcs.default.cacheattributes.MaxMemoryIdleTimeSeconds=3600 |
| jcs.default.cacheattributes.ShrinkerIntervalSeconds=60 |
| jcs.default.elementattributes=org.apache.jcs.engine.ElementAttributes |
| jcs.default.elementattributes.IsEternal=false |
| jcs.default.elementattributes.MaxLifeSeconds=700 |
| jcs.default.elementattributes.IdleTime=1800 |
| jcs.default.elementattributes.IsSpool=true |
| jcs.default.elementattributes.IsRemote=true |
| jcs.default.elementattributes.IsLateral=true |
| ]]></source> |
| <p> |
| The default and region configuration settings have three |
| components. They define what auxiliaries are available, |
| how the cache should control the memory, and how the elements |
| should behave. This configuration tells all regions to use |
| an auxiliary called DC by default. It also establishes |
| several settings for memory management (see <a |
| href="BasicJCSConfiguration.html">Basic JCS Configuration</a> |
| for more information on the cacheattribute settings). In addition, |
| by default all regions will take these element configuration |
| settings. |
| </p> |
| <p> |
| These settings specify that elements are not eternal, i.e. they |
| can expire. By default elements are considered eternal. |
| </p> |
| <p> |
| You can define the maximum life of an item by setting the |
| <code>MaxLifeSeconds</code> parameter. If an item has been in |
| the cache for longer than the set number of seconds it will |
| not be retrieved on a get request. If you use the memory shrinker |
| the item will be actively removed from memory. Currently there is |
| no background disk shrinker, but the disk cache does allow for |
| a maximum number of keys (see <a |
| href="IndexedDiskAuxCache.html">Indexed Disk Cache</a> |
| for more information on the disk cache settings). |
| </p> |
| <p> |
| You can define the maximum time an item can live without being accessed |
| by setting the <code>IdleTime</code> parameter. This is different than |
| the <code>MaxMemoryIdleTimeSeconds</code> parameter, which just specifies |
| how long an object can be in memory before it is subjected to removal or |
| being spooled to a disk cache if it is available. Note: the <code>IdleTime</code> |
| parameter may not function properly for items retrieved from disk, |
| if you have a memory size of 0. |
| </p> |
| </subsection> |
| <p> |
| <code>IsSpool</code> determines whether or not the element can go to disk, |
| if a disk cache is configured for the region. |
| </p> |
| <p> |
| <code>IsRemote</code> determines whether or not the element can be sent |
| to a remote server, if one is configured for the region. |
| </p> |
| <p> |
| <code>IsLateral</code> determines whether or not the element can be laterally |
| distributed, if a lateral auxiliary is configured for the region. |
| </p> |
| </section> |
| </body> |
| </document> |
