Flatten RetryParams by removing BackoffParams layer.

src/main/java/com/google/api/gax/core/RetryParams.java

@@ -43,12 +43,18 @@
  */
 @AutoValue
 public abstract class RetryParams {
-  public abstract BackoffParams getRetryBackoff();
 
-  public abstract BackoffParams getTimeoutBackoff();
 
   public abstract Duration getTotalTimeout();
 
+  public abstract Duration getInitialRetryDelay();
+  public abstract double getRetryDelayMultiplier();
+  public abstract Duration getMaxRetryDelay();
+
+  public abstract Duration getInitialRpcTimeout();
+  public abstract double getRpcTimeoutMultiplier();
+  public abstract Duration getMaxRpcTimeout();
+
   public static Builder newBuilder() {
     return new AutoValue_RetryParams.Builder();
   }
@@ -59,9 +65,14 @@ public Builder toBuilder() {
 
   @AutoValue.Builder
   public abstract static class Builder {
-    public abstract Builder setRetryBackoff(BackoffParams retryBackoff);
 
-    public abstract Builder setTimeoutBackoff(BackoffParams timeoutBackoff);
+    public abstract Builder setInitialRetryDelay(Duration initialDelay);
+    public abstract Builder setRetryDelayMultiplier(double multiplier);
+    public abstract Builder setMaxRetryDelay(Duration maxDelay);
+
+    public abstract Builder setInitialRpcTimeout(Duration initialTimeout);
+    public abstract Builder setRpcTimeoutMultiplier(double multiplier);
+    public abstract Builder setMaxRpcTimeout(Duration maxTimeout);
 
     public abstract Builder setTotalTimeout(Duration totalTimeout);
 
@@ -72,6 +83,21 @@ public RetryParams build() {
       if (params.getTotalTimeout().getMillis() < 0) {
         throw new IllegalStateException("total timeout must not be negative");
       }
+      if (params.getInitialRetryDelay().getMillis() < 0) {
+        throw new IllegalStateException("initial retry delay must not be negative");
+      }
+      if (params.getInitialRpcTimeout().getMillis() < 0) {
+        throw new IllegalStateException("initial rpc timeout must not be negative");
+      }
+      if (params.getRetryDelayMultiplier() < 1.0 || params.getRpcTimeoutMultiplier() < 1.0) {
+        throw new IllegalStateException("multiplier must be at least 1");
+      }
+      if (params.getMaxRetryDelay().compareTo(params.getInitialRetryDelay()) < 0) {
+        throw new IllegalStateException("max retry delay must not be shorter than initial delay");
+      }
+      if (params.getMaxRpcTimeout().compareTo(params.getInitialRpcTimeout()) < 0) {
+        throw new IllegalStateException("max rpc timeout must not be shorter than initial timeout");
+      }
       return params;
     }
   }

src/main/java/com/google/api/gax/grpc/RetryingCallable.java

@@ -75,8 +75,8 @@ public ListenableFuture<ResponseT> futureCall(CallContext<RequestT> context) {
         new Retryer(
             context,
             result,
-            retryParams.getRetryBackoff().getInitialDelay(),
-            retryParams.getTimeoutBackoff().getInitialDelay(),
+            retryParams.getInitialRetryDelay(),
+            retryParams.getInitialRpcTimeout(),
             null);
     retryer.run();
     return result;
@@ -138,17 +138,17 @@ public void onFailure(Throwable throwable) {
               }
               long newRetryDelay =
                   (long) (retryDelay.getMillis() *
-                      retryParams.getRetryBackoff().getDelayMultiplier());
+                      retryParams.getRetryDelayMultiplier());
               newRetryDelay =
                   Math.min(newRetryDelay,
-                      retryParams.getRetryBackoff().getMaxDelay().getMillis());
+                      retryParams.getMaxRetryDelay().getMillis());
 
               long newRpcTimeout =
                   (long) (rpcTimeout.getMillis() *
-                      retryParams.getTimeoutBackoff().getDelayMultiplier());
+                      retryParams.getRpcTimeoutMultiplier());
               newRpcTimeout =
                   Math.min(newRpcTimeout,
-                      retryParams.getTimeoutBackoff().getMaxDelay().getMillis());
+                      retryParams.getMaxRpcTimeout().getMillis());
 
               long randomRetryDelay = ThreadLocalRandom.current().nextLong(retryDelay.getMillis());
               Retryer retryer = new Retryer(context, result,

src/test/java/com/google/api/gax/grpc/ApiCallableTest.java

@@ -31,7 +31,6 @@
 
 package com.google.api.gax.grpc;
 
-import com.google.api.gax.core.BackoffParams;
 import com.google.api.gax.core.RetryParams;
 import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
@@ -61,6 +60,7 @@
 import java.util.concurrent.ExecutionException;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+
 /**
  * Tests for {@link ApiCallable}.
  */
@@ -71,17 +71,15 @@ public class ApiCallableTest {
   private static final RetryParams testRetryParams;
 
   static {
-    BackoffParams backoff =
-        BackoffParams.newBuilder()
-            .setInitialDelay(Duration.millis(2L))
-            .setDelayMultiplier(1)
-            .setMaxDelay(Duration.millis(2L))
-            .build();
     testRetryParams =
         RetryParams.newBuilder()
-            .setRetryBackoff(backoff)
-            .setTimeoutBackoff(backoff)
-            .setTotalTimeout(Duration.millis(100L))
+            .setInitialRetryDelay(Duration.millis(2L))
+            .setRetryDelayMultiplier(1)
+            .setMaxRetryDelay(Duration.millis(2L))
+            .setInitialRpcTimeout(Duration.millis(2L))
+            .setRpcTimeoutMultiplier(1)
+            .setMaxRpcTimeout(Duration.millis(2L))
+            .setTotalTimeout(Duration.millis(10L))
             .build();
   }