question: private Map checkAndSetTrustedProviders ( String realm , CircleOfTrustDescriptor cotDescriptor ) throws COTException { Set tp = cotDescriptor . getTrustedProviders ( ) ; Map map = null ; if ( ( tp != null ) && ! tp . isEmpty ( ) ) { map = COTUtils . trustedProviderSetToProtocolMap ( tp , realm ) ; retainValidEntityIDs ( map , COTConstants . SAML2 , realm ) ; retainValidEntityIDs ( map , COTConstants . IDFF , realm ) ; retainValidEntityIDs ( map , COTConstants . WS_FED , realm ) ; } return map ; }
target:  This method filters out invalid entities from the trusted provider list.