feat: add FunctionalInterface annotation (#1515)

JoeWang1127 · web-flow · commit c460331cab6b · 2023-04-11T13:50:14.000-04:00
* feat: add `FunctionalInterface` annotation

* exclude internal api

* revise according to code review

* remove annotation on beta api

* remove annotation

* remove annotation
diff --git a/sdk-platform-java/api-common-java/src/main/java/com/google/api/core/ApiAsyncFunction.java b/sdk-platform-java/api-common-java/src/main/java/com/google/api/core/ApiAsyncFunction.java
@@ -34,6 +34,7 @@
  *
  * <p>It is similar to Guava's {@code AsyncFunction}, redeclared so that Guava can be shaded.
  */
+@FunctionalInterface
 public interface ApiAsyncFunction<I, O> {
   /**
    * Returns an output Future to use in place of the given input. The output Future need not be
diff --git a/sdk-platform-java/api-common-java/src/main/java/com/google/api/core/ApiFunction.java b/sdk-platform-java/api-common-java/src/main/java/com/google/api/core/ApiFunction.java
@@ -34,6 +34,7 @@
  *
  * <p>It is similar to Guava's {@code Function}, redeclared so that Guava can be shaded.
  */
+@FunctionalInterface
 public interface ApiFunction<F, T> {
   T apply(F input);
 }
diff --git a/sdk-platform-java/api-common-java/src/main/java/com/google/api/pathtemplate/ValidationException.java b/sdk-platform-java/api-common-java/src/main/java/com/google/api/pathtemplate/ValidationException.java
@@ -39,6 +39,7 @@
  */
 public class ValidationException extends IllegalArgumentException {
 
+  @FunctionalInterface
   public interface Supplier<T> {
     T get();
   }
diff --git a/sdk-platform-java/gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/FieldsExtractor.java b/sdk-platform-java/gax-java/gax-httpjson/src/main/java/com/google/api/gax/httpjson/FieldsExtractor.java
@@ -33,6 +33,7 @@
  * A functional interface to be implemented for each request message to extract specific fields from
  * it. For advanced usage only.
  */
+@FunctionalInterface
 public interface FieldsExtractor<RequestT, ParamsT> {
   ParamsT extract(RequestT request);
 }
diff --git a/sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/BidiStreamingCallable.java b/sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/BidiStreamingCallable.java
@@ -100,15 +100,7 @@ public void call(final BidiStreamObserver<RequestT, ResponseT> bidiObserver) {
   /** Listens to server responses and send requests when the network is free. */
   public void call(
       final BidiStreamObserver<RequestT, ResponseT> bidiObserver, ApiCallContext context) {
-    internalCall(
-        bidiObserver,
-        new ClientStreamReadyObserver<RequestT>() {
-          @Override
-          public void onReady(ClientStream<RequestT> stream) {
-            bidiObserver.onReady(stream);
-          }
-        },
-        context);
+    internalCall(bidiObserver, bidiObserver, context);
   }
 
   /**
@@ -183,11 +175,8 @@ public ClientStream<RequestT> splitCall(
       ResponseObserver<ResponseT> responseObserver, ApiCallContext context) {
     return internalCall(
         responseObserver,
-        new ClientStreamReadyObserver<RequestT>() {
-          @Override
-          public void onReady(ClientStream<RequestT> stream) {
-            // no op
-          }
+        stream -> {
+          // no op
         },
         context);
   }
diff --git a/sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ClientStreamReadyObserver.java b/sdk-platform-java/gax-java/gax/src/main/java/com/google/api/gax/rpc/ClientStreamReadyObserver.java
@@ -30,6 +30,7 @@
 package com.google.api.gax.rpc;
 
 /** A callback used to report that the {@link ClientStream} is ready to send more messages. */
+@FunctionalInterface
 public interface ClientStreamReadyObserver<V> {
   void onReady(ClientStream<V> stream);
 }

Original file line number	Diff line number	Diff line change
`@@ -34,6 +34,7 @@`
`34`	`34`	`*`
`35`	`35`	`* <p>It is similar to Guava's {@code AsyncFunction}, redeclared so that Guava can be shaded.`
`36`	`36`	`*/`
	`37`	`+@FunctionalInterface`
`37`	`38`	`public interface ApiAsyncFunction<I, O> {`
`38`	`39`	`/**`
`39`	`40`	`* Returns an output Future to use in place of the given input. The output Future need not be`
Original file line number	Diff line number	Diff line change
`@@ -39,6 +39,7 @@`
`39`	`39`	`*/`
`40`	`40`	`public class ValidationException extends IllegalArgumentException {`
`41`	`41`
	`42`	`+ @FunctionalInterface`
`42`	`43`	`public interface Supplier<T> {`
`43`	`44`	`T get();`
`44`	`45`	`}`
Original file line number	Diff line number	Diff line change
`@@ -33,6 +33,7 @@`
`33`	`33`	`* A functional interface to be implemented for each request message to extract specific fields from`
`34`	`34`	`* it. For advanced usage only.`
`35`	`35`	`*/`
	`36`	`+@FunctionalInterface`
`36`	`37`	`public interface FieldsExtractor<RequestT, ParamsT> {`
`37`	`38`	`ParamsT extract(RequestT request);`
`38`	`39`	`}`
Original file line number	Diff line number	Diff line change
`@@ -30,6 +30,7 @@`
`30`	`30`	`package com.google.api.gax.rpc;`
`31`	`31`
`32`	`32`	`/** A callback used to report that the {@link ClientStream} is ready to send more messages. */`
	`33`	`+@FunctionalInterface`
`33`	`34`	`public interface ClientStreamReadyObserver<V> {`
`34`	`35`	`void onReady(ClientStream<V> stream);`
`35`	`36`	`}`