public Collection<Object> values() {
        return CollectionUtils.isEmpty(this.combinedPrincipals) ? Collections.emptySet()
                : Collections.unmodifiableCollection(this.combinedPrincipals.values());
    }
Default implementation of the {@link PrincipalMap} interface.
<p>
*EXPERIMENTAL for Shiro 1.2 - DO NOT USE YET*

@since 1.2
core/src/main/java/org/apache/shiro/subject/SimplePrincipalMap.java