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.

Author: sugmanue

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
+        AdaptiveRetryStrategy strategy = DefaultAdaptiveRetryStrategy2
             .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())

core/retries/src/main/java/software/amazon/awssdk/retries/AdaptiveRetryStrategy.java

@@ -21,7 +21,7 @@
 import software.amazon.awssdk.retries.api.AcquireInitialTokenRequest;
 import software.amazon.awssdk.retries.api.BackoffStrategy;
 import software.amazon.awssdk.retries.api.RetryStrategy;
-import software.amazon.awssdk.retries.internal.DefaultAdaptiveRetryStrategy;
+import software.amazon.awssdk.retries.internal.DefaultAdaptiveRetryStrategy2;
 import software.amazon.awssdk.retries.internal.circuitbreaker.TokenBucketStore;
 import software.amazon.awssdk.retries.internal.ratelimiter.RateLimiterTokenBucketStore;
 
@@ -63,7 +63,7 @@ public interface AdaptiveRetryStrategy extends RetryStrategy<AdaptiveRetryStrate
      * </pre>
      */
     static AdaptiveRetryStrategy.Builder builder() {
-        return DefaultAdaptiveRetryStrategy
+        return DefaultAdaptiveRetryStrategy2
             .builder()
             .maxAttempts(DefaultRetryStrategy.Adaptive.MAX_ATTEMPTS)
             .tokenBucketStore(TokenBucketStore.builder()

core/retries/src/main/java/software/amazon/awssdk/retries/LegacyRetryStrategy.java

@@ -20,7 +20,7 @@
 import software.amazon.awssdk.annotations.ThreadSafe;
 import software.amazon.awssdk.retries.api.BackoffStrategy;
 import software.amazon.awssdk.retries.api.RetryStrategy;
-import software.amazon.awssdk.retries.internal.DefaultLegacyRetryStrategy;
+import software.amazon.awssdk.retries.internal.DefaultLegacyRetryStrategy2;
 import software.amazon.awssdk.retries.internal.circuitbreaker.TokenBucketStore;
 
 /**
@@ -59,7 +59,7 @@ public interface LegacyRetryStrategy extends RetryStrategy<LegacyRetryStrategy.B
      * </pre>
      */
     static Builder builder() {
-        return DefaultLegacyRetryStrategy
+        return DefaultLegacyRetryStrategy2
             .builder()
             .maxAttempts(DefaultRetryStrategy.Legacy.MAX_ATTEMPTS)
             .tokenBucketStore(TokenBucketStore

core/retries/src/main/java/software/amazon/awssdk/retries/StandardRetryStrategy.java

@@ -19,7 +19,7 @@
 import software.amazon.awssdk.annotations.ThreadSafe;
 import software.amazon.awssdk.retries.api.BackoffStrategy;
 import software.amazon.awssdk.retries.api.RetryStrategy;
-import software.amazon.awssdk.retries.internal.DefaultStandardRetryStrategy;
+import software.amazon.awssdk.retries.internal.DefaultStandardRetryStrategy2;
 import software.amazon.awssdk.retries.internal.circuitbreaker.TokenBucketStore;
 
 /**
@@ -56,7 +56,7 @@ public interface StandardRetryStrategy extends RetryStrategy<StandardRetryStrate
      * </pre>
      */
     static Builder builder() {
-        return DefaultStandardRetryStrategy
+        return DefaultStandardRetryStrategy2
             .builder()
             .maxAttempts(DefaultRetryStrategy.Standard.MAX_ATTEMPTS)
             .tokenBucketStore(TokenBucketStore