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Each <dlm:fragment> element can contain from zero to many <dlm:audience> elements. Each audience element defines a group of users who will receive that fragment. If a fragment has more than one audience element then the set of users that get that fragment is the union of all nested audience elements.

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Define audiences using:

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GuestUserEvaluatorFactory
AllUsersEvaluatorFactory
PersonEvaluatorFactory
GroupMembershipEvaluatorFactory

The 'evaluatorFactory' Attribute

The <dlm:audience> element has a single required attribute, evaluatorFactory. This attribute should have the fully qualified path name of a class which implements the org.jasig.portal.layout.dlm.EvaluatorFactory interface for aquiring an evaluator. The factory implementation should have a zero argument constructor and implement the only method in the interface:

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The following evaluator factories are provided. All are found in the org.jasig.portal.layout.dlm.providers package.

The GuestUserEvaluatorFactory

This factory produces an evaluator that returns the value of IPerson.isGuest(). As such it does not use any configuration information within the audience element that declares it so the element can be empty. This factory is used in the version of dlm.xml included in the portal to push the Guest fragment to the guest user so that it shows on the log-in page.

<dlm:fragment name='Guests' ownerID='guest-lo' precedence='10'>
    <dlm:audience evaluatorFactory='org.jasig.portal.layout.dlm.providers.GuestUserEvaluatorFactory'/>
</dlm:fragment>

The AllUsersEvaluatorFactory

This factory produces and evaluator that always returns true. This can be used to push a fragment to all portal users including the guest user. Like GuestUserEvaluatorFactory it requires no content within the audience element and hence the element can be empty.

The PersonEvaluatorFactory

This factory produces an evaluator configured as defined by required content nested within its declaring audience element. It supports a configuration syntax from which arbitrarily complex grants of the fragment can be made based on attributes found in the passed-in IPerson object. Specifically, it obtains attributes from the IPerson object using the getAttribute call. The following syntax elements are supported.<paren> ELEMENT

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<dlm:fragment name='Entertainment' ownerID='ent-lo' precedence='100'>
  <dlm:audience evaluatorFactory='org.jasig.portal.layout.dlm.providers.PersonEvaluatorFactory'>
    <paren mode="NOT">
      <attribute name="username" mode='equals' value='guest'/>
    </paren>
  </dlm:audience>
</dlm:fragment>

The GroupMembershipEvaluatorFactory

This factory returns an evaluator that can evaluate group memberships. Specifically, the returned class inherits from the evaluator provided by PersonEvaluatorFactory. This means that its syntax semantics are identical except for the <attribute> element. Its semantics are overwritten to support 2 modes: memberOf and deepMemberOf. memberOf will test for membership of the named group only, whereas deepMemberOf will also test for membership in groups contained by the named group. The name attribute should contain the name of the group with matching case. The value attribute is not used. The News fragment in the default dlm.xml file in the portal uses this factory to push the news fragment to members of the Students group who are not also members of the Faculty group.

<dlm:fragment name='News' ownerID='news-lo' precedence='80'>
  <dlm:audience evaluatorFactory='org.jasig.portal.layout.dlm.providers.GroupMembershipEvaluatorFactory'>
    <paren mode="AND">
      <attribute mode='memberOf' name='Students'/>
      <paren mode="NOT">
        <attribute mode='memberOf' name='Faculty'/>
      </paren>
    </paren>
  </dlm:audience>
</dlm:fragment>