Polish FilterComparator

Extracts STEP incrementing into a separate helper class

config/src/main/java/org/springframework/security/config/annotation/web/builders/FilterComparator.java

@@ -56,83 +56,53 @@ import org.springframework.web.filter.CorsFilter;
 
 @SuppressWarnings("serial")
 final class FilterComparator implements Comparator<Filter>, Serializable {
-	private static final int STEP = 100;
-	private Map<String, Integer> filterToOrder = new HashMap<>();
+	private static final int INITIAL_ORDER = 100;
+	private static final int ORDER_STEP = 100;
+	private final Map<String, Integer> filterToOrder = new HashMap<>();
 
 	FilterComparator() {
-		int order = 100;
-		put(ChannelProcessingFilter.class, order);
-		order += STEP;
-		put(ConcurrentSessionFilter.class, order);
-		order += STEP;
-		put(WebAsyncManagerIntegrationFilter.class, order);
-		order += STEP;
-		put(SecurityContextPersistenceFilter.class, order);
-		order += STEP;
-		put(HeaderWriterFilter.class, order);
-		order += STEP;
-		put(CorsFilter.class, order);
-		order += STEP;
-		put(CsrfFilter.class, order);
-		order += STEP;
-		put(LogoutFilter.class, order);
-		order += STEP;
+		Step order = new Step(INITIAL_ORDER, ORDER_STEP);
+		put(ChannelProcessingFilter.class, order.next());
+		put(ConcurrentSessionFilter.class, order.next());
+		put(WebAsyncManagerIntegrationFilter.class, order.next());
+		put(SecurityContextPersistenceFilter.class, order.next());
+		put(HeaderWriterFilter.class, order.next());
+		put(CorsFilter.class, order.next());
+		put(CsrfFilter.class, order.next());
+		put(LogoutFilter.class, order.next());
 		filterToOrder.put(
 			"org.springframework.security.oauth2.client.web.OAuth2AuthorizationRequestRedirectFilter",
-			order);
-		order += STEP;
-		put(X509AuthenticationFilter.class, order);
-		order += STEP;
-		put(AbstractPreAuthenticatedProcessingFilter.class, order);
-		order += STEP;
+				order.next());
+		put(X509AuthenticationFilter.class, order.next());
+		put(AbstractPreAuthenticatedProcessingFilter.class, order.next());
 		filterToOrder.put("org.springframework.security.cas.web.CasAuthenticationFilter",
-				order);
-		order += STEP;
+				order.next());
 		filterToOrder.put(
 			"org.springframework.security.oauth2.client.web.OAuth2LoginAuthenticationFilter",
-			order);
-		order += STEP;
-		put(UsernamePasswordAuthenticationFilter.class, order);
-		order += STEP;
-		put(ConcurrentSessionFilter.class, order);
-		order += STEP;
+				order.next());
+		put(UsernamePasswordAuthenticationFilter.class, order.next());
+		put(ConcurrentSessionFilter.class, order.next());
 		filterToOrder.put(
-				"org.springframework.security.openid.OpenIDAuthenticationFilter", order);
-		order += STEP;
-		put(DefaultLoginPageGeneratingFilter.class, order);
-		order += STEP;
-		put(DefaultLogoutPageGeneratingFilter.class, order);
-		order += STEP;
-		put(ConcurrentSessionFilter.class, order);
-		order += STEP;
-		put(DigestAuthenticationFilter.class, order);
-		order += STEP;
+				"org.springframework.security.openid.OpenIDAuthenticationFilter", order.next());
+		put(DefaultLoginPageGeneratingFilter.class, order.next());
+		put(DefaultLogoutPageGeneratingFilter.class, order.next());
+		put(ConcurrentSessionFilter.class, order.next());
+		put(DigestAuthenticationFilter.class, order.next());
 		filterToOrder.put(
-				"org.springframework.security.oauth2.server.resource.web.BearerTokenAuthenticationFilter", order);
-		order += STEP;
-		put(BasicAuthenticationFilter.class, order);
-		order += STEP;
-		put(RequestCacheAwareFilter.class, order);
-		order += STEP;
-		put(SecurityContextHolderAwareRequestFilter.class, order);
-		order += STEP;
-		put(JaasApiIntegrationFilter.class, order);
-		order += STEP;
-		put(RememberMeAuthenticationFilter.class, order);
-		order += STEP;
-		put(AnonymousAuthenticationFilter.class, order);
-		order += STEP;
+				"org.springframework.security.oauth2.server.resource.web.BearerTokenAuthenticationFilter", order.next());
+		put(BasicAuthenticationFilter.class, order.next());
+		put(RequestCacheAwareFilter.class, order.next());
+		put(SecurityContextHolderAwareRequestFilter.class, order.next());
+		put(JaasApiIntegrationFilter.class, order.next());
+		put(RememberMeAuthenticationFilter.class, order.next());
+		put(AnonymousAuthenticationFilter.class, order.next());
 		filterToOrder.put(
 			"org.springframework.security.oauth2.client.web.OAuth2AuthorizationCodeGrantFilter",
-			order);
-		order += STEP;
-		put(SessionManagementFilter.class, order);
-		order += STEP;
-		put(ExceptionTranslationFilter.class, order);
-		order += STEP;
-		put(FilterSecurityInterceptor.class, order);
-		order += STEP;
-		put(SwitchUserFilter.class, order);
+				order.next());
+		put(SessionManagementFilter.class, order.next());
+		put(ExceptionTranslationFilter.class, order.next());
+		put(FilterSecurityInterceptor.class, order.next());
+		put(SwitchUserFilter.class, order.next());
 	}
 
 	public int compare(Filter lhs, Filter rhs) {
@@ -226,4 +196,23 @@ final class FilterComparator implements Comparator<Filter>, Serializable {
 		}
 		return null;
 	}
+
+	private static class Step {
+
+		private int value;
+		private final int stepSize;
+
+		Step(int initialValue, int stepSize) {
+			this.value = initialValue;
+			this.stepSize = stepSize;
+		}
+
+		int next() {
+			int value = this.value;
+			this.value += this.stepSize;
+			return value;
+		}
+
+	}
+
 }