Change FunctionCatalog to key off Class<?>

Makes it possible to support other "function" types in the future.
The user is always taking a risk with the lookup that the object
returned has the generic type desired (but that hasn't changed
with this commit). FunctionCatalog is a lot simpler as a result
and also a lot more flexible.

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionController.java

@@ -30,7 +30,6 @@ import org.springframework.http.HttpStatus;
 import org.springframework.http.ResponseEntity;
 import org.springframework.stereotype.Component;
 import org.springframework.web.bind.annotation.GetMapping;
-import org.springframework.web.bind.annotation.PathVariable;
 import org.springframework.web.bind.annotation.PostMapping;
 import org.springframework.web.bind.annotation.RequestAttribute;
 import org.springframework.web.bind.annotation.RequestBody;
@@ -52,8 +51,11 @@ public class FunctionController {
 
 	private boolean debug = false;
 
-	public FunctionController(FunctionInspector inspector) {
+	private StringConverter converter;
+
+	public FunctionController(FunctionInspector inspector, StringConverter converter) {
 		this.inspector = inspector;
+		this.converter = converter;
 	}
 
 	public void setDebug(boolean debug) {
@@ -115,9 +117,8 @@ public class FunctionController {
 		return debug ? result.log() : result;
 	}
 
-	private Mono<?> value(Function<Flux<?>, Flux<?>> function,
-			@PathVariable String value) {
-		Object input = inspector.convert(function, value);
+	private Mono<?> value(Function<Flux<?>, Flux<?>> function, String value) {
+		Object input = converter.convert(function, value);
 		Mono<?> result = Mono.from(function.apply(Flux.just(input)));
 		if (logger.isDebugEnabled()) {
 			logger.debug("Handled GET with function");

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/FunctionHandlerMapping.java

@@ -27,7 +27,6 @@ import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
 import org.springframework.cloud.function.context.FunctionCatalog;
-import org.springframework.cloud.function.context.catalog.FunctionInspector;
 import org.springframework.cloud.function.web.flux.constants.WebRequestConstants;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.util.StringUtils;
@@ -55,11 +54,12 @@ public class FunctionHandlerMapping extends RequestMappingHandlerMapping
 	private String debug = "false";
 
 	@Autowired
-	public FunctionHandlerMapping(FunctionCatalog catalog, FunctionInspector inspector) {
+	public FunctionHandlerMapping(FunctionCatalog catalog,
+			FunctionController controller) {
 		this.functions = catalog;
-		logger.info("FunctionCatalog: " + catalog + ", FunctionInspector: " + inspector);
+		logger.info("FunctionCatalog: " + catalog);
 		setOrder(super.getOrder() - 5);
-		this.controller = new FunctionController(inspector);
+		this.controller = controller;
 	}
 
 	@Override
@@ -118,12 +118,12 @@ public class FunctionHandlerMapping extends RequestMappingHandlerMapping
 			return null;
 		}
 		path = path.startsWith("/") ? path.substring(1) : path;
-		Consumer<Object> consumer = functions.lookupConsumer(path);
+		Consumer<Object> consumer = functions.lookup(Consumer.class, path);
 		if (consumer != null) {
 			request.setAttribute(WebRequestConstants.CONSUMER, consumer);
 			return consumer;
 		}
-		Function<Object, Object> function = functions.lookupFunction(path);
+		Function<Object, Object> function = functions.lookup(Function.class, path);
 		if (function != null) {
 			request.setAttribute(WebRequestConstants.FUNCTION, function);
 			return function;
@@ -136,7 +136,7 @@ public class FunctionHandlerMapping extends RequestMappingHandlerMapping
 			return null;
 		}
 		path = path.startsWith("/") ? path.substring(1) : path;
-		Supplier<Object> supplier = functions.lookupSupplier(path);
+		Supplier<Object> supplier = functions.lookup(Supplier.class, path);
 		if (supplier != null) {
 			request.setAttribute(WebRequestConstants.SUPPLIER, supplier);
 			return supplier;
@@ -152,7 +152,7 @@ public class FunctionHandlerMapping extends RequestMappingHandlerMapping
 			name = builder.toString();
 			value = path.length() > name.length() ? path.substring(name.length() + 1)
 					: null;
-			Function<Object, Object> function = functions.lookupFunction(name);
+			Function<Object, Object> function = functions.lookup(Function.class, name);
 			if (function != null) {
 				request.setAttribute(WebRequestConstants.FUNCTION, function);
 				request.setAttribute(WebRequestConstants.ARGUMENT, value);

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/ReactorAutoConfiguration.java

@@ -23,8 +23,10 @@ import com.google.gson.Gson;
 
 import org.springframework.beans.factory.SmartInitializingSingleton;
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.boot.autoconfigure.AutoConfigureBefore;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
+import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingClass;
 import org.springframework.boot.autoconfigure.condition.ConditionalOnWebApplication;
 import org.springframework.boot.autoconfigure.web.HttpMessageConverters;
@@ -36,6 +38,9 @@ import org.springframework.cloud.function.web.flux.response.FluxReturnValueHandl
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.core.convert.ConversionService;
+import org.springframework.core.convert.support.DefaultConversionService;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.GsonHttpMessageConverter;
 import org.springframework.util.ClassUtils;
@@ -54,6 +59,7 @@ import reactor.core.publisher.Flux;
 @ConditionalOnWebApplication
 @ConditionalOnClass({ Flux.class, AsyncHandlerMethodReturnValueHandler.class })
 @AutoConfigureBefore(HttpMessageConvertersAutoConfiguration.class)
+@Import(FunctionController.class)
 public class ReactorAutoConfiguration {
 
 	@Autowired
@@ -61,8 +67,15 @@ public class ReactorAutoConfiguration {
 
 	@Bean
 	public FunctionHandlerMapping functionHandlerMapping(FunctionCatalog catalog,
-			FunctionInspector inspector) {
-		return new FunctionHandlerMapping(catalog, inspector);
+			FunctionController controller) {
+		return new FunctionHandlerMapping(catalog, controller);
+	}
+
+	@Bean
+	@ConditionalOnMissingBean
+	public StringConverter functionStringConverter(FunctionInspector inspector,
+			ConfigurableListableBeanFactory beanFactory) {
+		return new BasicStringConverter(inspector, beanFactory);
 	}
 
 	// TODO: remove this when https://jira.spring.io/browse/SPR-16529 is resolved
@@ -125,4 +138,32 @@ public class ReactorAutoConfiguration {
 
 		};
 	}
+
+	private static class BasicStringConverter implements StringConverter {
+
+		private ConversionService conversionService;
+		private ConfigurableListableBeanFactory registry;
+		private FunctionInspector inspector;
+
+		public BasicStringConverter(FunctionInspector inspector,
+				ConfigurableListableBeanFactory registry) {
+			this.inspector = inspector;
+			this.registry = registry;
+		}
+
+		@Override
+		public Object convert(Object function, String value) {
+			if (conversionService == null && registry != null) {
+				ConversionService conversionService = this.registry
+						.getConversionService();
+				this.conversionService = conversionService != null ? conversionService
+						: new DefaultConversionService();
+			}
+			Class<?> type = inspector.getInputType(function);
+			return conversionService.canConvert(String.class, type)
+					? conversionService.convert(value, type)
+					: value;
+		}
+
+	}
 }

spring-cloud-function-web/src/main/java/org/springframework/cloud/function/web/flux/StringConverter.java

@@ -0,0 +1,26 @@
+/*
+ * Copyright 2016-2017 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.cloud.function.web.flux;
+
+/**
+ * @author Dave Syer
+ *
+ */
+public interface StringConverter {
+
+	Object convert(Object function, String value);
+
+}