question: public void beginDisplay ( DisplayEvent event ) throws ModelControlException { IdentitySubjectModel subjectModel = getSubjectModel ( ) ; PolicyModel model = ( PolicyModel ) getModel ( ) ; super . beginDisplay ( event ) ; CCDropDownMenu menu = ( CCDropDownMenu ) getChild ( FILTER_TYPE ) ; Map supportedEntityTypes = model . getSupportedEntityTypes ( realmName ) ; OptionList entityTypes = createOptionList ( supportedEntityTypes ) ; entityTypes . add ( 0 , "policy.subject.select.identity.type" , "" ) ; menu . setOptions ( entityTypes ) ; menu . setValue ( "" ) ; CCAddRemove child = ( CCAddRemove ) getChild ( VALUES_MULTIPLE_CHOICE_VALUE ) ; child . restoreStateData ( ) ; OptionList selected = addRemoveModel . getSelectedOptionList ( ) ; OptionList possible = helper . createOptionList ( model . getUserSSOToken ( ) , model . getUserLocale ( ) , this , getPossibleValues ( subjectModel , realmName ) ) ; child . resetStateData ( ) ; addRemoveModel . setAvailableOptionList ( possible ) ; }
target:  Sets the values to UI model.