Refactor BindingContext initialization

In preparation for SPR-15132.

Turn the BindingContextFactory into ModelInitializer (both package
private) since creating BindingContext itself is quite simple.

The ModelInitializer also has only one field and no need to be aware
of fields the RequestMappingHandlerAdapter.

spring-webflux/src/test/java/org/springframework/web/reactive/result/method/annotation/ModelInitializerTests.java

@@ -17,14 +17,17 @@
 package org.springframework.web.reactive.result.method.annotation;
 
 import java.util.Collections;
+import java.util.List;
 import java.util.Map;
+import java.util.stream.Collectors;
 
 import org.junit.Before;
 import org.junit.Test;
 import reactor.core.publisher.Mono;
 import rx.Single;
 
-import org.springframework.context.support.StaticApplicationContext;
+import org.springframework.core.MethodIntrospector;
+import org.springframework.core.ReactiveAdapterRegistry;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
 import org.springframework.ui.Model;
@@ -34,35 +37,35 @@ import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.InitBinder;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.support.ConfigurableWebBindingInitializer;
+import org.springframework.web.bind.support.WebBindingInitializer;
 import org.springframework.web.bind.support.WebExchangeDataBinder;
-import org.springframework.web.method.HandlerMethod;
 import org.springframework.web.reactive.BindingContext;
-import org.springframework.web.reactive.config.WebFluxConfigurationSupport;
-import org.springframework.web.reactive.result.ResolvableMethod;
+import org.springframework.web.reactive.result.method.InvocableHandlerMethod;
+import org.springframework.web.reactive.result.method.SyncInvocableHandlerMethod;
 import org.springframework.web.server.ServerWebExchange;
 import org.springframework.web.server.adapter.DefaultServerWebExchange;
 
 import static org.junit.Assert.assertEquals;
 import static org.mockito.Mockito.mock;
+import static org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.INIT_BINDER_METHODS;
+import static org.springframework.web.reactive.result.method.annotation.RequestMappingHandlerAdapter.MODEL_ATTRIBUTE_METHODS;
 
 /**
- * Unit tests for {@link BindingContextFactory}.
+ * Unit tests for {@link ModelInitializer}.
  * @author Rossen Stoyanchev
  */
-public class BindingContextFactoryTests {
+public class ModelInitializerTests {
 
-	private BindingContextFactory contextFactory;
+	private ModelInitializer modelInitializer;
 
 	private ServerWebExchange exchange;
 
 
 	@Before
 	public void setup() throws Exception {
-		WebFluxConfigurationSupport configurationSupport = new WebFluxConfigurationSupport();
-		configurationSupport.setApplicationContext(new StaticApplicationContext());
-		RequestMappingHandlerAdapter adapter = configurationSupport.requestMappingHandlerAdapter();
-		adapter.afterPropertiesSet();
-		this.contextFactory = new BindingContextFactory(adapter);
+
+		this.modelInitializer = new ModelInitializer(new ReactiveAdapterRegistry());
 
 		MockServerHttpRequest request = MockServerHttpRequest.get("/path").build();
 		MockServerHttpResponse response = new MockServerHttpResponse();
@@ -74,15 +77,15 @@ public class BindingContextFactoryTests {
 	@Test
 	public void basic() throws Exception {
 		Validator validator = mock(Validator.class);
-		TestController controller = new TestController(validator);
+		Object controller = new TestController(validator);
 
-		HandlerMethod handlerMethod = ResolvableMethod.on(controller)
-				.annotated(RequestMapping.class)
-				.resolveHandlerMethod();
+		List<SyncInvocableHandlerMethod> binderMethods = getBinderMethods(controller);
+		List<InvocableHandlerMethod> attributeMethods = getAttributeMethods(controller);
 
-		BindingContext bindingContext =
-				this.contextFactory.createBindingContext(handlerMethod, this.exchange)
-						.blockMillis(5000);
+		WebBindingInitializer bindingInitializer = new ConfigurableWebBindingInitializer();
+		BindingContext bindingContext = new InitBinderBindingContext(bindingInitializer, binderMethods);
+
+		this.modelInitializer.initModel(bindingContext, attributeMethods, this.exchange).blockMillis(5000);
 
 		WebExchangeDataBinder binder = bindingContext.createDataBinder(this.exchange, "name");
 		assertEquals(Collections.singletonList(validator), binder.getValidators());
@@ -106,6 +109,24 @@ public class BindingContextFactoryTests {
 		assertEquals("Void Mono Method Bean", ((TestBean) value).getName());
 	}
 
+	private List<SyncInvocableHandlerMethod> getBinderMethods(Object controller) {
+		return MethodIntrospector
+				.selectMethods(controller.getClass(), INIT_BINDER_METHODS).stream()
+				.map(method -> new SyncInvocableHandlerMethod(controller, method))
+				.collect(Collectors.toList());
+	}
+
+	private List<InvocableHandlerMethod> getAttributeMethods(Object controller) {
+		return MethodIntrospector
+				.selectMethods(controller.getClass(), MODEL_ATTRIBUTE_METHODS).stream()
+				.map(method -> {
+					InvocableHandlerMethod invocable = new InvocableHandlerMethod(controller, method);
+					invocable.setArgumentResolvers(Collections.singletonList(new ModelArgumentResolver()));
+					return invocable;
+				})
+				.collect(Collectors.toList());
+	}
+
 
 	@SuppressWarnings("unused")
 	private static class TestController {