Using Scala trait to consume OSGi services via DS

/*
 * Scala trait to hold Configuration Admin
 */
package com.yours.app

import org.osgi.service.cm.ConfigurationAdmin

trait ConfigAdminHolder {
    protected var configAdmin: Option[ConfigurationAdmin] = None

    def bindConfigAdmin(ca: ConfigurationAdmin): Unit = configAdmin = Some(ca)
    def unbindConfigAdmin(ca: ConfigurationAdmin): Unit = configAdmin = None
}

/*
 * OSGi component
 */
class Component extends ConfigAdminHolder {
  def someMethod { /* make use of configAdmin */ }
}

/*
 * OSGi component XML
 */
<?xml version="1.0" encoding="UTF-8"?>
<component name="My component">
    <implementation class="com.yours.app.Component"/>
    <reference
        name="ConfigAdmin Service"
        interface="org.osgi.service.cm.ConfigurationAdmin"
        bind="bindConfigAdmin"
        unbind="unbindConfigAdmin"
        cardinality="1..1"
        policy="dynamic"/>
</component>