/**
* Creates a security filter. Initialization parameters are found in facebook.security.properties file that must be placed
* in the same package as the FacebookDefaultSecurityFilter
*/
public FacebookDefaultSecurityFilter(){
factory = new FacebookClientFactory();
userFbId = new HashMap<String, String>();
userAccessToken = new HashMap<String, String>();
ownerAttributeName = new LinkedList<String>();
cache = new LinkedHashMap<String, IFacebookRESTClient>(50, 0.75f, true);