[infinispan-issues] [JBoss JIRA] Commented: (ISPN-312) Ability to group data entries

[Pete Muir (JIRA)]

    [ https://issues.jboss.org/browse/ISPN-312?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12599310#comment-12599310 ] 

Pete Muir commented on ISPN-312:
--------------------------------

I propose two APIs for controlling this. The first, where you have control of the key class you can annotate the key class directly, either providing a static group:

{code}
@Group("com.acme.hr") class Employee { ... }
{code}

or a dynamic group

{code}
@Group class Employee { 

   String group;

   ...
 
   @Group
   String getGroup() {
      return group;
   }

 }
{code}

If an annotation is used at class level with the value attribute provided, then this will be used as the group id. If no value attribute is specified, then there must be a method annotated @Group with no attribute, there must be no arguments to the method and the return type of the method must be String. Whenever the group of the key needs identifying then this method will be called. The impl will cache the annotation information in order to not incur large amounts of runtime overhead on annotation inspection.

In the case where the key class cannot be modified, then a group generator can be registered using Infinispan Configuration, which should implement the GroupGenerator interface:

{code}
interface GroupGenerator<T> {

   String generateGroup(T key);

}{code}

For example, a group generator for String keys which encode the group info in their namespace might look like:

{code}
class StringGroupGenerator implements GroupGenerator<String> {

   Pattern namespacePattern;

   // Initialize the pattern e.g. match com.acme.hr from any key com.acme.hr.<personName>

   String generate(String key) {
      return namespacePattern.split(key)[0];
   }

}
{code}

Obviously the code above is not very safe, but serves as a basic example for now ;-)

> Ability to group data entries
> -----------------------------
>
>                 Key: ISPN-312
>                 URL: https://issues.jboss.org/browse/ISPN-312
>             Project: Infinispan
>          Issue Type: Feature Request
>          Components: Core API, Distributed Cache, Eviction, Locking and Concurrency
>    Affects Versions: 4.0.0.Final, 4.1.0.Final
>            Reporter: Mindaugas Žakšauskas
>            Assignee: Pete Muir
>            Priority: Minor
>              Labels: cache, colocation, group, grouping
>             Fix For: 5.1.0.BETA1
>
>
> This is a spin-off from http://lists.jboss.org/pipermail/infinispan-dev/2009-December/001968.html.
> The requested feature would allow distinct entries to be assigned to custom arbitrary groups. Later in time those groups could be flushed on demand without any knowledge of entry keys.
> This feature exists in other open source cache library, see: http://www.opensymphony.com/oscache/api/com/opensymphony/oscache/base/Cache.html

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