Refactor storage driver context to be interface.

Author: cconstable

temporal-sdk/src/main/java/io/temporal/payload/storage/StorageDriverRetrieveContext.java

@@ -2,6 +2,11 @@
 
 import io.temporal.common.Experimental;
 
-/** Context passed to {@link StorageDriver#retrieve}. */
+/**
+ * Context passed to {@link StorageDriver#retrieve}.
+ *
+ * <p>Implemented by the SDK and passed to the driver. Driver authors do not implement this in
+ * production code, only when constructing instances for their own tests.
+ */
 @Experimental
-public final class StorageDriverRetrieveContext {}
+public interface StorageDriverRetrieveContext {}

temporal-sdk/src/main/java/io/temporal/payload/storage/StorageDriverStoreContext.java

@@ -3,17 +3,18 @@
 import io.temporal.common.Experimental;
 import javax.annotation.Nullable;
 
-/** Context passed to {@link StorageDriver#store} and {@link StorageDriverSelector}. */
+/**
+ * Context passed to {@link StorageDriver#store} and {@link StorageDriverSelector}.
+ *
+ * <p>Implemented by the SDK and passed to the driver. Driver authors do not implement this in
+ * production code, only when constructing instances for their own tests.
+ */
 @Experimental
-public final class StorageDriverStoreContext {
-  private final @Nullable StorageDriverTargetInfo target;
-
-  public StorageDriverStoreContext(@Nullable StorageDriverTargetInfo target) {
-    this.target = target;
-  }
-
+public interface StorageDriverStoreContext {
+  /**
+   * Identity of the workflow or activity the payload is being stored for, or {@code null} when it
+   * is not available.
+   */
   @Nullable
-  public StorageDriverTargetInfo getTarget() {
-    return target;
-  }
+  StorageDriverTargetInfo getTarget();
 }

temporal-sdk/src/test/java/io/temporal/payload/storage/ExternalStorageTest.java

@@ -13,6 +13,15 @@
 
 public class ExternalStorageTest {
 
+  private static StorageDriverStoreContext storeContext(StorageDriverTargetInfo target) {
+    return new StorageDriverStoreContext() {
+      @Override
+      public StorageDriverTargetInfo getTarget() {
+        return target;
+      }
+    };
+  }
+
   private static StorageDriver driver(String name) {
     return new StorageDriver() {
       @Override
@@ -46,9 +55,7 @@ public void singleDriverNoSelectorSynthesizesSelector() {
     assertEquals(1, storage.getDrivers().size());
     StorageDriverSelector selector = storage.getDriverSelector();
     assertNotNull(selector);
-    assertSame(
-        a,
-        selector.selectDriver(new StorageDriverStoreContext(null), Payload.getDefaultInstance()));
+    assertSame(a, selector.selectDriver(storeContext(null), Payload.getDefaultInstance()));
   }
 
   @Test