Refactor retry strategies (#4039)

* Refactor the retry strategies

This change uses a single class to implement the core logic of all the
retries strategies and adds extension points to tailor the behavior
when needed.

* Rename to BaseRetryStrategy and make it abstract

* Remove previous implementations and rename the new ones

build-tools/src/main/java/software/amazon/awssdk/buildtools/findbugs/ToBuilderIsCorrect.java

@@ -212,11 +212,15 @@ public void visit(Method method) {
             }
         } else if (isBuildable && method.getName().equals("toBuilder") && method.getSignature().startsWith("()")) {
             // This is a buildable toBuilder
-            constructorsInvokedFromToBuilder.computeIfAbsent(getDottedClassName(), n -> new HashMap<>());
-            toBuilderModifiedFields.computeIfAbsent(getDottedClassName(), n -> new HashMap<>());
+            String dottedClassName = getDottedClassName();
+            constructorsInvokedFromToBuilder.computeIfAbsent(dottedClassName, n -> new HashMap<>());
+            toBuilderModifiedFields.computeIfAbsent(dottedClassName, n -> new HashMap<>());
             inBuildableToBuilder = true;
             inBuilderConstructor = false;
-
+            if (method.isAbstract()) {
+                // Ignore abstract toBuilder methods, we will still validate the actual implementations.
+                ignoredBuildables.add(dottedClassName);
+            }
             registerIgnoredFields();
         } else {
             inBuildableToBuilder = false;

core/retries/src/it/java/software/amazon/awssdk/retries/internal/AdaptiveRetryStrategyResourceConstrainedTest.java

@@ -51,6 +51,7 @@
  * perceived availability for the clients to be close to 1.0.
  */
 class AdaptiveRetryStrategyResourceConstrainedTest {
+    static final int DEFAULT_EXCEPTION_TOKEN_COST = 5;
 
     @Test
     void seemsToBeCorrectAndThreadSafe() {
@@ -61,12 +62,12 @@ void seemsToBeCorrectAndThreadSafe() {
         int parallelism = serverWorkers + clientWorkers;
         ExecutorService executor = Executors.newFixedThreadPool(parallelism);
         Server server = new Server(serverWorkers, executor);
-        RateLimiterTokenBucketStore store = RateLimiterTokenBucketStore.builder().build();
         AdaptiveRetryStrategy strategy = DefaultAdaptiveRetryStrategy
             .builder()
             // We don't care about how many attempts we allow to, that logic is tested somewhere else.
             // so we give the strategy plenty of room for retries.
             .maxAttempts(20)
+            .tokenBucketExceptionCost(DEFAULT_EXCEPTION_TOKEN_COST)
             .tokenBucketStore(TokenBucketStore.builder().tokenBucketMaxCapacity(10_000).build())
             // Just wait for the rate limiter delays.
             .backoffStrategy(BackoffStrategy.retryImmediately())