examples/spellcheckbinder/src/main/resources/metadata.xml

<?xml version="1.0" encoding="UTF-8"?>
<bundle>
  <!--
     This metadata file instructs the Apache Felix Service Binder to
     create one instance of "SpellCheckServiceImpl". It also
     tells the generic activator that this instance implements the
     "SpellCheckService" service interface and that it has an
     aggregate dependency on "DictionaryService" services. Since
     the service dependency on dictionary services has a lower
     cardinality of one, the generic activator will create the instance
     and offer its spell check service only when there is at least
     one dictionary service available. The service dependency is
     "dynamic", which means that dictionary service availability
     will be monitored dynamically at runtime and it also tells the
     generic activator which methods to call when adding and removing
     dictionary services.
    -->
  <instance class="org.apache.felix.examples.spellcheckbinder.SpellCheckServiceImpl">
    <service interface="org.apache.felix.examples.spellcheckservice.SpellCheckService"/>
    <requires
      service="org.apache.felix.examples.dictionaryservice.DictionaryService"
      filter="(Language=*)"
      cardinality="1..n"
      policy="dynamic"
      bind-method="addDictionary"
      unbind-method="removeDictionary"
    />
  </instance>
</bundle>