Declare BodySource a sealed interface

http-client/src/main/java/com/proofpoint/http/client/BodySource.java

@@ -15,7 +15,8 @@
  */
 package com.proofpoint.http.client;
 
-public interface BodySource
+public sealed interface BodySource
+    permits DynamicBodySource, InputStreamBodySource, StaticBodyGenerator
 {
     /**
      * @return the content length, if known, or -1 if the content length is unknown

http-client/src/main/java/com/proofpoint/http/client/DynamicBodySource.java

@@ -17,7 +17,8 @@
 
 import java.io.OutputStream;
 
-public interface DynamicBodySource extends BodySource
+public non-sealed interface DynamicBodySource
+        extends BodySource
 {
     /**
      * Start writing the request body.

http-client/src/main/java/com/proofpoint/http/client/InputStreamBodySource.java

@@ -21,7 +21,7 @@
 
 import static com.google.common.base.Preconditions.checkState;
 
-public class InputStreamBodySource
+public non-sealed class InputStreamBodySource
     implements BodySource, LimitedRetryable
 {
     private final InputStream inputStream;

http-client/src/main/java/com/proofpoint/http/client/StaticBodyGenerator.java

@@ -19,7 +19,7 @@
 
 import java.nio.charset.Charset;
 
-public class StaticBodyGenerator implements BodySource
+public non-sealed class StaticBodyGenerator implements BodySource
 {
     public static StaticBodyGenerator createStaticBodyGenerator(String body, Charset charset)
     {

http-client/src/test/java/com/proofpoint/http/client/TestRequest.java

@@ -19,6 +19,7 @@
 import com.google.common.collect.ListMultimap;
 import org.testng.annotations.Test;
 
+import java.io.OutputStream;
 import java.net.URI;
 
 import static com.proofpoint.http.client.Request.Builder.prepareGet;
@@ -115,8 +116,13 @@ private static ListMultimap<String, String> createHeadersB()
 
     public static BodySource createBodySource()
     {
-        return new BodySource()
+        return new DynamicBodySource()
         {
+            @Override
+            public Writer start(OutputStream out) throws Exception
+            {
+                throw new UnsupportedOperationException();
+            }
         };
     }
 }

http-client/src/test/java/com/proofpoint/http/client/TestRequestBuilder.java

@@ -18,6 +18,7 @@
 import com.google.common.collect.ImmutableListMultimap;
 import org.testng.annotations.Test;
 
+import java.io.OutputStream;
 import java.net.URI;
 
 import static com.proofpoint.http.client.Request.Builder.fromRequest;
@@ -30,8 +31,8 @@
 
 public class TestRequestBuilder
 {
-    public static final BodySource NULL_BODY_SOURCE = new BodySource()
-    {
+    public static final BodySource NULL_BODY_SOURCE = (DynamicBodySource) out -> {
+        throw new UnsupportedOperationException();
     };
 
     @Test

http-client/src/test/java/com/proofpoint/http/client/balancing/AbstractTestBalancingHttpClient.java

@@ -16,6 +16,7 @@
 package com.proofpoint.http.client.balancing;
 
 import com.proofpoint.http.client.BodySource;
+import com.proofpoint.http.client.DynamicBodySource;
 import com.proofpoint.http.client.HttpClient;
 import com.proofpoint.http.client.LimitedRetryable;
 import com.proofpoint.http.client.Request;
@@ -108,7 +109,7 @@ protected void setUp()
                 .setMinBackoff(new Duration(1, TimeUnit.MILLISECONDS))
                 .setMaxBackoff(new Duration(2, TimeUnit.MILLISECONDS));
         balancingHttpClient = createBalancingHttpClient();
-        bodySource = mock(BodySource.class);
+        bodySource = mock(DynamicBodySource.class);
         request = preparePut().setUri(URI.create("v1/service")).setBodySource(bodySource).build();
         requestArgumentCaptor = ArgumentCaptor.forClass(Request.class);
         response = mock(Response.class);

http-client/src/test/java/com/proofpoint/http/client/balancing/TestBalancingHttpClient.java

@@ -100,7 +100,7 @@ class TestingHttpClient
         private String method;
         private List<URI> uris = new ArrayList<>();
         private List<Object> responses = new ArrayList<>();
-        private boolean skipBodyGenerator = false;
+        private boolean skipBodySource = false;
 
         TestingHttpClient(String method)
         {
@@ -130,7 +130,7 @@ private TestingHttpClient expectCall(URI uri, Object response)
         @Override
         public  TestingClient firstCallNoBodyGenerator()
         {
-            skipBodyGenerator = true;
+            skipBodySource = true;
             return this;
         }
 
@@ -155,8 +155,8 @@ public <T, E extends Exception> T execute(Request request, ResponseHandler<T, E>
             assertEquals(request.getUri(), uris.remove(0), "request uri");
             assertEquals(request.getBodySource(), bodySource, "request body generator");
 
-            if (skipBodyGenerator) {
-                skipBodyGenerator = false;
+            if (skipBodySource) {
+                skipBodySource = false;
             }
             else if (bodySource instanceof LimitedRetryable) {
                 try {