What's difference between ROLE_ANONYMOUS and IS_AUTHENTICATED_ANONYMOUSLY

[tony9427]

In acegi security sample tutorial, configuration is

<bean id="filterInvocationInterceptor" class="org.acegisecurity.intercept.web.FilterSecurityInterceptor">
		<property name="authenticationManager" ref="authenticationManager"/>
		<property name="accessDecisionManager">
			<bean class="org.acegisecurity.vote.AffirmativeBased">
				<property name="allowIfAllAbstainDecisions" value="false"/>
				<property name="decisionVoters">
					<list>
						<bean class="org.acegisecurity.vote.RoleVoter"/>
						<bean class="org.acegisecurity.vote.AuthenticatedVoter"/>
					</list>
				</property>
			</bean>
		</property>
		<property name="objectDefinitionSource">
			<value>
				CONVERT_URL_TO_LOWERCASE_BEFORE_COMPARISON
				PATTERN_TYPE_APACHE_ANT
				/secure/extreme/**=ROLE_SUPERVISOR
				/secure/**=IS_AUTHENTICATED_REMEMBERED
				/**=IS_AUTHENTICATED_ANONYMOUSLY
			</value>
		</property>
	</bean>

While in acegi-security-sample-contacts-filter, configuration is:

<property name="objectDefinitionSource">
         <value>
			    CONVERT_URL_TO_LOWERCASE_BEFORE_COMPARISON
			    PATTERN_TYPE_APACHE_ANT
			    /index.jsp=ROLE_ANONYMOUS,ROLE_USER
			    /hello.htm=ROLE_ANONYMOUS,ROLE_USER
			    /logoff.jsp=ROLE_ANONYMOUS,ROLE_USER
			    /switchuser.jsp=ROLE_SUPERVISOR
			    /j_acegi_switch_user=ROLE_SUPERVISOR
			    /acegilogin.jsp*=ROLE_ANONYMOUS,ROLE_USER
				/**=ROLE_USER
         </value>
      </property>

What's the difference for ROLE_ANONYMOUS and IS_AUTHENTICATED_ANONYMOUSLY? Where is attribute like IS_AUTHENTICATED_ANONYMOUSLY and PATTERN_TYPE_APACHE_ANT
from?

Thanks in advance!