revoke API change

RateLimiter: keep api as stable as possible.

java/org/apache/catalina/filters/RateLimitFilter.java

@@ -17,7 +17,6 @@
 package org.apache.catalina.filters;
 
 import java.io.IOException;
-import java.util.concurrent.ScheduledExecutorService;
 
 import jakarta.servlet.FilterChain;
 import jakarta.servlet.FilterConfig;
@@ -30,7 +29,6 @@
 import org.apache.juli.logging.Log;
 import org.apache.juli.logging.LogFactory;
 import org.apache.tomcat.util.res.StringManager;
-import org.apache.tomcat.util.threads.ScheduledThreadPoolExecutor;
 
 /**
  * <p>
@@ -202,30 +200,23 @@ protected boolean isConfigProblemFatal() {
     public void init(FilterConfig filterConfig) throws ServletException {
         super.init(filterConfig);
 
-        ScheduledExecutorService utilityExecutor = (ScheduledExecutorService) filterConfig.getServletContext()
-                .getAttribute(ScheduledThreadPoolExecutor.class.getName());
-        if (utilityExecutor == null) {
-            if (newExecutorService == null) {
-                newExecutorService = new java.util.concurrent.ScheduledThreadPoolExecutor(1);
-            }
-            utilityExecutor = newExecutorService;
-        }
-
         try {
             rateLimiter = (RateLimiter) Class.forName(rateLimitClassName).getConstructor().newInstance();
         } catch (ReflectiveOperationException e) {
             throw new ServletException(e);
         }
 
+        rateLimiter.setDuration(bucketDuration);
+        rateLimiter.setRequests(bucketRequests);
+        rateLimiter.setFilterConfig(filterConfig);
+
         if (policyName != null) {
             String trimmedName = policyName.trim();
             if (!trimmedName.isEmpty()) {
                 rateLimiter.setPolicyName(trimmedName);
             }
         }
 
-        rateLimiter.initialize(utilityExecutor, bucketDuration, bucketRequests);
-
         filterName = filterConfig.getFilterName();
 
         log.info(sm.getString("rateLimitFilter.initialized", filterName, Integer.valueOf(bucketRequests),
@@ -262,18 +253,9 @@ public void doFilter(ServletRequest request, ServletResponse response, FilterCha
         chain.doFilter(request, response);
     }
 
-    private ScheduledExecutorService newExecutorService = null;
-
     @Override
     public void destroy() {
         rateLimiter.destroy();
-        if (newExecutorService != null) {
-            try {
-                newExecutorService.shutdown();
-            } catch (SecurityException e) {
-                // ignore
-            }
-        }
         super.destroy();
     }
 

java/org/apache/catalina/util/FastRateLimiter.java

@@ -33,4 +33,9 @@ protected String getDefaultPolicyName() {
     protected TimeBucketCounterBase newCounterInstance(ScheduledExecutorService executorService, int duration) {
         return new TimeBucketCounter(executorService, duration);
     }
+
+    @Override
+    public TimeBucketCounter getBucketCounter() {
+        return (TimeBucketCounter)bucketCounter;
+    }
 }

java/org/apache/catalina/util/RateLimiter.java

@@ -17,7 +17,7 @@
 
 package org.apache.catalina.util;
 
-import java.util.concurrent.ScheduledExecutorService;
+import jakarta.servlet.FilterConfig;
 
 public interface RateLimiter {
 
@@ -26,11 +26,25 @@ public interface RateLimiter {
      */
     int getDuration();
 
+    /**
+     * Sets the configured duration value in seconds.
+     *
+     * @param duration The duration of the time window in seconds
+     */
+    void setDuration(int duration);
+
     /**
      * @return the maximum number of requests allowed per time window
      */
     int getRequests();
 
+    /**
+     * Sets the configured number of requests allowed per time window.
+     *
+     * @param requests The number of requests per time window
+     */
+    void setRequests(int requests);
+
     /**
      * Increments the number of requests by the given identifier in the current time window.
      *
@@ -46,13 +60,11 @@ public interface RateLimiter {
     void destroy();
 
     /**
-     * Initialize with parameters, start {@link TimeBucketCounterBase}.
+     * Pass the FilterConfig to configure the filter.
      *
-     * @param executorService the executor
-     * @param duration        the duration of the time window in seconds
-     * @param requests        the configured number of requests allowed per time window
+     * @param filterConfig The FilterConfig used to configure the associated filter
      */
-    void initialize(ScheduledExecutorService executorService, int duration, int requests);
+    void setFilterConfig(FilterConfig filterConfig);
 
     /**
      * @return name of RateLimit policy
@@ -80,7 +92,7 @@ default String getPolicy() {
     /**
      * Provide the quota header for this rate limit for a given request count within the current time window.
      *
-     * @param requestCount The request count within the current time window
+     * @param requestCount  The request count within the current time window
      *
      * @return the quota header for the given value of request count
      *

java/org/apache/catalina/util/RateLimiterBase.java

@@ -18,8 +18,11 @@
 
 import java.util.Objects;
 import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.ScheduledThreadPoolExecutor;
 import java.util.concurrent.atomic.AtomicInteger;
 
+import jakarta.servlet.FilterConfig;
+
 /**
  * Basic implementation of {@link RateLimiter}, provides runtime data maintenance mechanism monitor.
  */
@@ -29,8 +32,10 @@ public abstract class RateLimiterBase implements RateLimiter {
 
     TimeBucketCounterBase bucketCounter;
 
+    int requests;
     int actualRequests;
 
+    int duration;
     int actualDuration;
 
     // Initial policy name can be rewritten by setPolicyName()
@@ -63,11 +68,21 @@ public int getDuration() {
         return actualDuration;
     }
 
+    @Override
+    public void setDuration(int duration) {
+        this.duration=duration;
+    }
+
     @Override
     public int getRequests() {
         return actualRequests;
     }
 
+    @Override
+    public void setRequests(int requests) {
+        this.requests=requests;
+    }
+
     @Override
     public int increment(String identifier) {
         return bucketCounter.increment(identifier);
@@ -76,6 +91,13 @@ public int increment(String identifier) {
     @Override
     public void destroy() {
         bucketCounter.destroy();
+        if (newExecutorService != null) {
+            try {
+                newExecutorService.shutdown();
+            } catch (SecurityException e) {
+                // ignore
+            }
+        }
     }
 
     /**
@@ -90,17 +112,20 @@ public void destroy() {
     protected abstract TimeBucketCounterBase newCounterInstance(ScheduledExecutorService utilityExecutor, int duration);
 
     @Override
-    public void initialize(ScheduledExecutorService utilityExecutor, int duration, int requests) {
-        if (bucketCounter != null) {
-            bucketCounter.destroy();
-        }
+    public void setFilterConfig(FilterConfig filterConfig) {
+
+        ScheduledExecutorService executorService = (ScheduledExecutorService) filterConfig.getServletContext()
+                .getAttribute(ScheduledThreadPoolExecutor.class.getName());
 
-        bucketCounter = newCounterInstance(utilityExecutor, duration);
+        if (executorService == null) {
+            newExecutorService = new java.util.concurrent.ScheduledThreadPoolExecutor(1);
+            executorService = newExecutorService;
+        }
 
+        bucketCounter = newCounterInstance(executorService, duration);
         actualDuration = bucketCounter.getBucketDuration();
         actualRequests = (int) Math.round(bucketCounter.getRatio() * requests);
     }
-
     /**
      * Returns the internal instance of {@link TimeBucketCounterBase}
      *
@@ -109,4 +134,10 @@ public void initialize(ScheduledExecutorService utilityExecutor, int duration, i
     public TimeBucketCounterBase getBucketCounter() {
         return bucketCounter;
     }
+
+    /**
+     * The self-owned utility executor, will be instantiated only when ScheduledThreadPoolExecutor is absent during
+     * filter configure phase.
+     */
+    private ScheduledThreadPoolExecutor newExecutorService = null;
 }