chore: expose user set executor on TransportProvider

This allows service clients to reuse that executor for other transport related things in addition to gax

Author: igorbernstein2

java-bigtable/google-cloud-bigtable/src/main/java/com/google/cloud/bigtable/gaxx/grpc/BigtableTransportChannelProvider.java

@@ -74,6 +74,12 @@ public boolean needsExecutor() {
     return delegate.needsExecutor();
   }
 
+  @Nullable
+  @Override
+  public Executor getExecutor() {
+    return delegate.getExecutor();
+  }
+
   @Override
   @Deprecated
   public BigtableTransportChannelProvider withExecutor(ScheduledExecutorService executor) {

sdk-platform-java/gax-java/gax-grpc/src/main/java/com/google/api/gax/grpc/InstantiatingGrpcChannelProvider.java

@@ -264,6 +264,12 @@ public boolean needsExecutor() {
     return executor == null;
   }
 
+  @Nullable
+  @Override
+  public Executor getExecutor() {
+    return executor;
+  }
+
   @Deprecated
   @Override
   public TransportChannelProvider withExecutor(ScheduledExecutorService executor) {

sdk-platform-java/gax-java/gax-grpc/src/test/java/com/google/api/gax/grpc/testing/LocalChannelProvider.java

@@ -53,6 +53,7 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.regex.Pattern;
+import javax.annotation.Nullable;
 
 /** LocalChannelProvider creates channels for in-memory gRPC services. */
 @BetaApi
@@ -80,6 +81,12 @@ public boolean needsExecutor() {
     return false;
   }
 
+  @Nullable
+  @Override
+  public Executor getExecutor() {
+    return null;
+  }
+
   @Deprecated
   @Override
   public TransportChannelProvider withExecutor(ScheduledExecutorService executor) {

sdk-platform-java/gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/InstantiatingHttpJsonChannelProvider.java

@@ -105,6 +105,12 @@ public boolean needsExecutor() {
     return executor == null;
   }
 
+  @Nullable
+  @Override
+  public Executor getExecutor() {
+    return executor;
+  }
+
   @Deprecated
   @Override
   public TransportChannelProvider withExecutor(ScheduledExecutorService executor) {

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/FixedTransportChannelProvider.java

@@ -36,6 +36,7 @@
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
+import javax.annotation.Nullable;
 
 /** An instance of TransportChannelProvider that always provides the same TransportChannel. */
 @InternalExtensionOnly
@@ -57,6 +58,12 @@ public boolean needsExecutor() {
     return false;
   }
 
+  @Nullable
+  @Override
+  public Executor getExecutor() {
+    return null;
+  }
+
   @Override
   public FixedTransportChannelProvider withExecutor(ScheduledExecutorService executor) {
     return withExecutor((Executor) executor);

sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/TransportChannelProvider.java

@@ -36,6 +36,7 @@
 import java.util.Map;
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
+import javax.annotation.Nullable;
 
 /**
  * Provides an interface to either build a TransportChannel or provide a fixed TransportChannel that
@@ -70,6 +71,13 @@ public interface TransportChannelProvider {
   @Deprecated
   boolean needsExecutor();
 
+  /**
+   * @return the user provided executor. This can be null if the user didn't override the executor
+   *     and the TransportProvider is using its internal executor.
+   */
+  @Nullable
+  Executor getExecutor();
+
   /** Sets the executor to use when constructing a new {@link TransportChannel}. */
   TransportChannelProvider withExecutor(Executor executor);
 

sdk-platform-java/gax-java/gax/src/test/java/com/google/api/gax/rpc/ClientContextTest.java

@@ -70,6 +70,7 @@
 import java.util.concurrent.Executor;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.ScheduledThreadPoolExecutor;
+import javax.annotation.Nullable;
 import org.junit.jupiter.api.Test;
 import org.mockito.Mockito;
 
@@ -147,6 +148,12 @@ public boolean needsExecutor() {
       return executor == null;
     }
 
+    @Nullable
+    @Override
+    public Executor getExecutor() {
+      return executor;
+    }
+
     @Override
     public TransportChannelProvider withExecutor(ScheduledExecutorService executor) {
       return withExecutor((Executor) executor);