Add ConcurrentModel

This commit adds a Model implementation based on ConcurrentHashMap for
use in Spring Web Reactive.

Issue: SPR-14542

spring-context/src/main/java/org/springframework/ui/ConcurrentModel.java

+/*
+ * Copyright 2002-2016 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.ui;
+
+import java.util.Collection;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+
+import org.springframework.core.Conventions;
+import org.springframework.util.Assert;
+
+/**
+ * Implementation of {@link Model} based on a {@link ConcurrentHashMap} for use
+ * in concurrent scenarios. Exposed to handler methods by Spring Web Reactive
+ * typically via a declaration of the {@link Model} interface. There is typically
+ * no need to create it within user code. If necessary a controller method can
+ * return a regular {@code java.util.Map}, or more likely a
+ * {@code java.util.ConcurrentMap}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ */
+@SuppressWarnings("serial")
+public class ConcurrentModel extends ConcurrentHashMap<String, Object> implements Model {
+
+	/**
+	 * Construct a new, empty {@code ConcurrentModel}.
+	 */
+	public ConcurrentModel() {
+	}
+
+	/**
+	 * Construct a new {@code ModelMap} containing the supplied attribute
+	 * under the supplied name.
+	 * @see #addAttribute(String, Object)
+	 */
+	public ConcurrentModel(String attributeName, Object attributeValue) {
+		addAttribute(attributeName, attributeValue);
+	}
+
+	/**
+	 * Construct a new {@code ModelMap} containing the supplied attribute.
+	 * Uses attribute name generation to generate the key for the supplied model
+	 * object.
+	 * @see #addAttribute(Object)
+	 */
+	public ConcurrentModel(Object attributeValue) {
+		addAttribute(attributeValue);
+	}
+
+
+	/**
+	 * Add the supplied attribute under the supplied name.
+	 * @param attributeName the name of the model attribute (never {@code null})
+	 * @param attributeValue the model attribute value (can be {@code null})
+	 */
+	public ConcurrentModel addAttribute(String attributeName, Object attributeValue) {
+		Assert.notNull(attributeName, "Model attribute name must not be null");
+		put(attributeName, attributeValue);
+		return this;
+	}
+
+	/**
+	 * Add the supplied attribute to this {@code Map} using a
+	 * {@link org.springframework.core.Conventions#getVariableName generated name}.
+	 * <p><emphasis>Note: Empty {@link Collection Collections} are not added to
+	 * the model when using this method because we cannot correctly determine
+	 * the true convention name. View code should check for {@code null} rather
+	 * than for empty collections as is already done by JSTL tags.</emphasis>
+	 * @param attributeValue the model attribute value (never {@code null})
+	 */
+	public ConcurrentModel addAttribute(Object attributeValue) {
+		Assert.notNull(attributeValue, "Model object must not be null");
+		if (attributeValue instanceof Collection && ((Collection<?>) attributeValue).isEmpty()) {
+			return this;
+		}
+		return addAttribute(Conventions.getVariableName(attributeValue), attributeValue);
+	}
+
+	/**
+	 * Copy all attributes in the supplied {@code Collection} into this
+	 * {@code Map}, using attribute name generation for each element.
+	 * @see #addAttribute(Object)
+	 */
+	public ConcurrentModel addAllAttributes(Collection<?> attributeValues) {
+		if (attributeValues != null) {
+			for (Object attributeValue : attributeValues) {
+				addAttribute(attributeValue);
+			}
+		}
+		return this;
+	}
+
+	/**
+	 * Copy all attributes in the supplied {@code Map} into this {@code Map}.
+	 * @see #addAttribute(String, Object)
+	 */
+	public ConcurrentModel addAllAttributes(Map<String, ?> attributes) {
+		if (attributes != null) {
+			putAll(attributes);
+		}
+		return this;
+	}
+
+	/**
+	 * Copy all attributes in the supplied {@code Map} into this {@code Map},
+	 * with existing objects of the same name taking precedence (i.e. not getting
+	 * replaced).
+	 */
+	public ConcurrentModel mergeAttributes(Map<String, ?> attributes) {
+		if (attributes != null) {
+			for (Map.Entry<String, ?> entry : attributes.entrySet()) {
+				String key = entry.getKey();
+				if (!containsKey(key)) {
+					put(key, entry.getValue());
+				}
+			}
+		}
+		return this;
+	}
+
+	/**
+	 * Does this model contain an attribute of the given name?
+	 * @param attributeName the name of the model attribute (never {@code null})
+	 * @return whether this model contains a corresponding attribute
+	 */
+	public boolean containsAttribute(String attributeName) {
+		return containsKey(attributeName);
+	}
+
+	@Override
+	public Map<String, Object> asMap() {
+		return this;
+	}
+
+}

spring-context/src/main/java/org/springframework/validation/support/BindingAwareConcurrentModel.java

+/*
+ * Copyright 2002-2015 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.validation.support;
+
+import java.util.Map;
+
+import org.springframework.ui.ConcurrentModel;
+import org.springframework.validation.BindingResult;
+
+/**
+ * Sub-class of {@link ConcurrentModel} that automatically removes
+ * the {@link BindingResult} object when its corresponding
+ * target attribute is replaced through regular {@link Map} operations.
+ *
+ * <p>This is the class exposed to controller methods by Spring Web Reactive,
+ * typically consumed through a declaration of the
+ * {@link org.springframework.ui.Model} interface. There is typically
+ * no need to create it within user code. If necessary a controller method can
+ * return a regular {@code java.util.Map}, or more likely a
+ * {@code java.util.ConcurrentMap}.
+ *
+ * @author Rossen Stoyanchev
+ * @since 5.0
+ * @see BindingResult
+ */
+@SuppressWarnings("serial")
+public class BindingAwareConcurrentModel extends ConcurrentModel {
+
+	@Override
+	public Object put(String key, Object value) {
+		removeBindingResultIfNecessary(key, value);
+		return super.put(key, value);
+	}
+
+	@Override
+	public void putAll(Map<? extends String, ?> map) {
+		map.entrySet().forEach(e -> removeBindingResultIfNecessary(e.getKey(), e.getValue()));
+		super.putAll(map);
+	}
+
+	private void removeBindingResultIfNecessary(String key, Object value) {
+		if (!key.startsWith(BindingResult.MODEL_KEY_PREFIX)) {
+			String bindingResultKey = BindingResult.MODEL_KEY_PREFIX + key;
+			BindingResult bindingResult = (BindingResult) get(bindingResultKey);
+			if (bindingResult != null && bindingResult.getTarget() != value) {
+				remove(bindingResultKey);
+			}
+		}
+	}
+
+}

spring-web-reactive/src/main/java/org/springframework/web/reactive/HandlerResult.java

@@ -23,8 +23,8 @@ import reactor.core.publisher.Mono;
 
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ResolvableType;
-import org.springframework.ui.ExtendedModelMap;
-import org.springframework.ui.ModelMap;
+import org.springframework.ui.ConcurrentModel;
+import org.springframework.ui.Model;
 import org.springframework.util.Assert;
 
 /**
@@ -42,7 +42,7 @@ public class HandlerResult {
 
 	private final ResolvableType returnType;
 
-	private final ModelMap model;
+	private final Model model;
 
 	private Function<Throwable, Mono<HandlerResult>> exceptionHandler;
 
@@ -64,13 +64,13 @@ public class HandlerResult {
 	 * @param returnType the return value type
 	 * @param model the model used for request handling
 	 */
-	public HandlerResult(Object handler, Object returnValue, MethodParameter returnType, ModelMap model) {
+	public HandlerResult(Object handler, Object returnValue, MethodParameter returnType, Model model) {
 		Assert.notNull(handler, "'handler' is required");
 		Assert.notNull(returnType, "'returnType' is required");
 		this.handler = handler;
 		this.returnValue = Optional.ofNullable(returnValue);
 		this.returnType = ResolvableType.forMethodParameter(returnType);
-		this.model = (model != null ? model : new ExtendedModelMap());
+		this.model = (model != null ? model : new ConcurrentModel());
 	}
 
 
@@ -107,7 +107,7 @@ public class HandlerResult {
 	 * Return the model used during request handling with attributes that may be
 	 * used to render HTML templates with.
 	 */
-	public ModelMap getModel() {
+	public Model getModel() {
 		return this.model;
 	}
 

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/BindingContext.java

@@ -15,9 +15,8 @@
  */
 package org.springframework.web.reactive.result.method;
 
-import org.springframework.beans.TypeConverter;
-import org.springframework.ui.ModelMap;
-import org.springframework.validation.support.BindingAwareModelMap;
+import org.springframework.ui.Model;
+import org.springframework.validation.support.BindingAwareConcurrentModel;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.WebExchangeDataBinder;
 import org.springframework.web.bind.support.WebBindingInitializer;
@@ -33,12 +32,10 @@ import org.springframework.web.server.ServerWebExchange;
  */
 public class BindingContext {
 
-	private final ModelMap model = new BindingAwareModelMap();
+	private final Model model = new BindingAwareConcurrentModel();
 
 	private final WebBindingInitializer initializer;
 
-	private final TypeConverter simpleValueTypeConverter;
-
 
 	public BindingContext() {
 		this(null);
@@ -46,7 +43,6 @@ public class BindingContext {
 
 	public BindingContext(WebBindingInitializer initializer) {
 		this.initializer = initializer;
-		this.simpleValueTypeConverter = initTypeConverter(initializer);
 	}
 
 	private static WebExchangeDataBinder initTypeConverter(WebBindingInitializer initializer) {
@@ -61,7 +57,7 @@ public class BindingContext {
 	/**
 	 * Return the default model.
 	 */
-	public ModelMap getModel() {
+	public Model getModel() {
 		return this.model;
 	}
 

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/InvocableHandlerMethod.java

@@ -32,6 +32,7 @@ import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.GenericTypeResolver;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.ParameterNameDiscoverer;
+import org.springframework.ui.Model;
 import org.springframework.ui.ModelMap;
 import org.springframework.util.ClassUtils;
 import org.springframework.util.ObjectUtils;
@@ -101,7 +102,7 @@ public class InvocableHandlerMethod extends HandlerMethod {
 		return resolveArguments(exchange, bindingContext, providedArgs).then(args -> {
 			try {
 				Object value = doInvoke(args);
-				ModelMap model = bindingContext.getModel();
+				Model model = bindingContext.getModel();
 				HandlerResult handlerResult = new HandlerResult(this, value, getReturnType(), model);
 				return Mono.just(handlerResult);
 			}

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/AbstractNamedValueArgumentResolver.java

@@ -27,7 +27,7 @@ import org.springframework.beans.factory.config.BeanExpressionContext;
 import org.springframework.beans.factory.config.BeanExpressionResolver;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.core.MethodParameter;
-import org.springframework.ui.ModelMap;
+import org.springframework.ui.Model;
 import org.springframework.web.bind.WebDataBinder;
 import org.springframework.web.bind.annotation.ValueConstants;
 import org.springframework.web.reactive.result.method.BindingContext;
@@ -87,7 +87,7 @@ public abstract class AbstractNamedValueArgumentResolver implements HandlerMetho
 					"Specified name must not resolve to null: [" + namedValueInfo.name + "]"));
 		}
 
-		ModelMap model = bindingContext.getModel();
+		Model model = bindingContext.getModel();
 
 		return resolveName(resolvedName.toString(), nestedParameter, exchange)
 				.map(arg -> {
@@ -186,7 +186,7 @@ public abstract class AbstractNamedValueArgumentResolver implements HandlerMetho
 	}
 
 	private Mono<Object> getDefaultValue(NamedValueInfo namedValueInfo, MethodParameter parameter,
-			BindingContext bindingContext, ModelMap model, ServerWebExchange exchange) {
+			BindingContext bindingContext, Model model, ServerWebExchange exchange) {
 
 		Object value = null;
 		try {
@@ -263,7 +263,7 @@ public abstract class AbstractNamedValueArgumentResolver implements HandlerMetho
 	 */
 	@SuppressWarnings("UnusedParameters")
 	protected void handleResolvedValue(Object arg, String name, MethodParameter parameter,
-			ModelMap model, ServerWebExchange exchange) {
+			Model model, ServerWebExchange exchange) {
 	}
 
 

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/PathVariableMethodArgumentResolver.java

@@ -22,7 +22,7 @@ import java.util.Optional;
 import org.springframework.beans.factory.config.ConfigurableBeanFactory;
 import org.springframework.core.MethodParameter;
 import org.springframework.core.convert.converter.Converter;
-import org.springframework.ui.ModelMap;
+import org.springframework.ui.Model;
 import org.springframework.util.StringUtils;
 import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.ValueConstants;
@@ -93,7 +93,7 @@ public class PathVariableMethodArgumentResolver extends AbstractNamedValueSyncAr
 	@Override
 	@SuppressWarnings("unchecked")
 	protected void handleResolvedValue(Object arg, String name, MethodParameter parameter,
-			ModelMap model, ServerWebExchange exchange) {
+			Model model, ServerWebExchange exchange) {
 
 		// TODO: View.PATH_VARIABLES ?
 	}

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/method/annotation/RequestMappingHandlerAdapter.java

@@ -329,7 +329,7 @@ public class RequestMappingHandlerAdapter implements HandlerAdapter, BeanFactory
 					logger.debug("Invoking @ExceptionHandler method: " + invocable.getMethod());
 				}
 				invocable.setArgumentResolvers(getArgumentResolvers());
-				bindingContext.getModel().clear();
+				bindingContext.getModel().asMap().clear();
 				return invocable.invoke(exchange, bindingContext, ex);
 			}
 			catch (Throwable invocationEx) {

spring-web-reactive/src/main/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandler.java

@@ -206,7 +206,7 @@ public class ViewResolutionResultHandler extends AbstractHandlerResultHandler
 					.defaultIfEmpty(result.getModel())
 					.then(model -> getDefaultViewNameMono(exchange, result));
 		}
-		Map<String, ?> model = result.getModel();
+		Map<String, ?> model = result.getModel().asMap();
 		return viewMono.then(view -> {
 			updateResponseStatus(result.getReturnTypeSource(), exchange);
 			if (view instanceof View) {

spring-web-reactive/src/test/java/org/springframework/web/reactive/result/view/ViewResolutionResultHandlerTests.java

@@ -49,7 +49,6 @@ import org.springframework.mock.http.server.reactive.test.MockServerHttpRequest;
 import org.springframework.mock.http.server.reactive.test.MockServerHttpResponse;
 import org.springframework.ui.ExtendedModelMap;
 import org.springframework.ui.Model;
-import org.springframework.ui.ModelMap;
 import org.springframework.web.bind.annotation.ModelAttribute;
 import org.springframework.web.bind.annotation.ResponseStatus;
 import org.springframework.web.reactive.HandlerResult;
@@ -80,7 +79,7 @@ public class ViewResolutionResultHandlerTests {
 
 	private ServerWebExchange exchange;
 
-	private ModelMap model = new ExtendedModelMap();
+	private Model model = new ExtendedModelMap();
 
 
 	@Before
@@ -184,7 +183,7 @@ public class ViewResolutionResultHandlerTests {
 	private void testDefaultViewName(Object returnValue, ResolvableType type)
 			throws URISyntaxException {
 
-		ModelMap model = new ExtendedModelMap().addAttribute("id", "123");
+		Model model = new ExtendedModelMap().addAttribute("id", "123");
 		HandlerResult result = new HandlerResult(new Object(), returnValue, returnType(type), model);
 		ViewResolutionResultHandler handler = createResultHandler(new TestViewResolver("account"));
 
@@ -290,7 +289,7 @@ public class ViewResolutionResultHandlerTests {
 	private void testHandle(String path, ResolvableMethod resolvableMethod, Object returnValue,
 			String responseBody, ViewResolver... resolvers) throws URISyntaxException {
 
-		ModelMap model = new ExtendedModelMap().addAttribute("id", "123");
+		Model model = new ExtendedModelMap().addAttribute("id", "123");
 		MethodParameter returnType = resolvableMethod.resolveReturnType();
 		HandlerResult result = new HandlerResult(new Object(), returnValue, returnType, model);
 		this.request.setUri(path);