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Difference between revisions of "EclipseLink/UserGuide/JPA/Basic JPA Development/Caching/Expiration"
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| − | =Cache Expiration= | + | =Cache Expiration and Invalidation= |
| − | By default, objects remain in the | + | By default, objects remain in the shared cache until they are explicitly deleted or garbage collected. |
| − | + | You can configure any object with a <tt>expiry</tt> that lets you specify, either the number of milliseconds after which an object should expire from the cache, or a time of day that all objects should expire from the cache. Expiry is set on the <tt>@Cache</tt> annotation or <tt><cache></tt> XML element, and can be configured in two ways: | |
| − | + | * <tt>expiry</tt> - The number of milliseconds to expiry an object in the cache after it has been read. | |
| + | * <tt>expiryTimeOfDay</tt> - The <tt>@TimeOfDay</tt> represent the 24h time of day to expiry all objects in the cache. | ||
| − | + | When an object expires, it is only invalidated in the cache. It is not removed from the cache, but when next accessed it will be refreshed from the database as part of the query that was used to access it. | |
| − | + | ||
| − | + | ||
| − | + | It is also possible to define your own expiry or invalidation policy by defining your own <tt>CacheInvalidationPolicy</tt> and setting it in your entity's descriptor using a <tt>DescriptorCustomizer</tt>. | |
| − | + | The application can also explicitly invalidate objects in the cache using the JPA <tt>Cache</tt> API, or the EclipseLink <tt>JpaCache</tt> API (see [[#Cache API|Cache API]]). | |
| − | + | ||
| − | + | ||
| − | + | Expiry can also be used in the query results cache (see [[#Query Results Cache|Query Results Cache]]). | |
| − | + | Invalidation can also be used in a cluster through cache coordination (see [[#Cache Coordination|Cache Coordination]]), or from database events using database event notification (see [[#Database Events Notification|Database Events Notification]]). | |
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|next=[[EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching/Coordination|Cache Coordination]] | |next=[[EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching/Coordination|Cache Coordination]] | ||
|up=[[EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching|Caching]] | |up=[[EclipseLink/UserGuide/JPA/Basic_JPA_Development/Caching|Caching]] | ||
| − | |version=2. | + | |version=2.4 DRAFT}} |
Revision as of 15:08, 10 May 2012
EclipseLink JPA
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Examples
Cache Expiration and Invalidation
By default, objects remain in the shared cache until they are explicitly deleted or garbage collected.
You can configure any object with a expiry that lets you specify, either the number of milliseconds after which an object should expire from the cache, or a time of day that all objects should expire from the cache. Expiry is set on the @Cache annotation or <cache> XML element, and can be configured in two ways:
- expiry - The number of milliseconds to expiry an object in the cache after it has been read.
- expiryTimeOfDay - The @TimeOfDay represent the 24h time of day to expiry all objects in the cache.
When an object expires, it is only invalidated in the cache. It is not removed from the cache, but when next accessed it will be refreshed from the database as part of the query that was used to access it.
It is also possible to define your own expiry or invalidation policy by defining your own CacheInvalidationPolicy and setting it in your entity's descriptor using a DescriptorCustomizer.
The application can also explicitly invalidate objects in the cache using the JPA Cache API, or the EclipseLink JpaCache API (see Cache API).
Expiry can also be used in the query results cache (see Query Results Cache).
Invalidation can also be used in a cluster through cache coordination (see Cache Coordination), or from database events using database event notification (see Database Events Notification).
