JBoss Application Server 4.3 Seam Reference Guide

8.6. Using Hibernate filters

The coolest, and most unique, feature of Hibernate is filters . Filters let you provide a restricted view of the data in the database. You can find out more about filters in the Hibernate documentation. But we thought we'd mention an easy way to incorporate filters into a Seam application, one that works especially well with the Seam Application Framework.

Seam-managed persistence contexts may have a list of filters defined, which will be enabled whenever an EntityManager or Hibernate Session is first created. (Of course, they may only be used when Hibernate is the underlying persistence provider.)

<core:filter name="regionFilter">
    <core:name>region</core:name>
    <core:parameters>
        <key>regionCode</key>
        <value>#{region.code}</value>
    </core:parameters>
</core:filter>

<core:filter name="currentFilter">
    <core:name>current</core:name>
    <core:parameters>
        <key>date</key>
        <value>#{currentDate}</value>
    </core:parameters>
</core:filter>

<core:managed-persistence-context name="personDatabase"
    persistence-unit-jndi-name="java:/EntityManagerFactories/personDatabase">
    <core:filters>
        <value>#{regionFilter}</value>
        <value>#{currentFilter}</value>
    </core:filters>
</core:managed-persistence-context>