Native compilation changes required in SCSt apps

- Instead of injecting `AbstractMappingMessageRouter[]`, inject it as a container
  type using `List<>`. This is because the former uses reflection behind the scenes
  and causes issues with graal native compilation (unless provided as a native hint).

- Instead of autowiring `Map<String, BindingTargetFactory>` in
  `AbstractBindableProxyFactory`, programmatically populate `BindingTargetFactory`
  beans by doing a `BeanFactory` lookup in a new method. Then the subclasses of
  `AbstractBindableProxyFactory` call this method to pouplate the avaialble
  `BindingTargetFactory` beans in their `afterPropertiesSet` method.

- Convert array injection of `BindableProxyFactory[]` in functionInitailzer bean
  in `FunctionConfiguration` to use container based injejction (`List<>`).

- Cleanup unused injection in functionInitializer bean in `FunctionConfiguration`.

Resolves https://github.com/spring-cloud/spring-cloud-stream/issues/2154

Resolves #2155

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binding/AbstractBindableProxyFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2019 the original author or authors.
+ * Copyright 2019-2021 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.
@@ -26,7 +26,8 @@ import java.util.Set;
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.ListableBeanFactory;
 import org.springframework.beans.factory.annotation.Value;
 import org.springframework.cloud.stream.binder.Binding;
 import org.springframework.cloud.stream.internal.InternalPropertyNames;
@@ -48,7 +49,6 @@ public class AbstractBindableProxyFactory implements Bindable {
 	@Value("${" + InternalPropertyNames.NAMESPACE_PROPERTY_NAME + ":}")
 	private String namespace;
 
-	@Autowired
 	protected Map<String, BindingTargetFactory> bindingTargetFactories;
 
 	protected Map<String, BoundTargetHolder> inputHolders = new LinkedHashMap<>();
@@ -57,10 +57,16 @@ public class AbstractBindableProxyFactory implements Bindable {
 
 	protected Class<?> type;
 
+	private BeanFactory beanFactory;
+
 	public AbstractBindableProxyFactory(Class<?> type) {
 		this.type = type;
 	}
 
+	protected void populateBindingTargetFactories(BeanFactory beanFactory) {
+		this.bindingTargetFactories = ((ListableBeanFactory) beanFactory).getBeansOfType(BindingTargetFactory.class);
+	}
+
 	protected BindingTargetFactory getBindingTargetFactory(Class<?> bindingTargetType) {
 		List<String> candidateBindingTargetFactories = new ArrayList<>();
 		for (Map.Entry<String, BindingTargetFactory> bindingTargetFactoryEntry : this.bindingTargetFactories

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/binding/BindableProxyFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2019 the original author or authors.
+ * Copyright 2015-2021 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.
@@ -26,6 +26,9 @@ import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
 import org.springframework.aop.framework.ProxyFactory;
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.BeanFactory;
+import org.springframework.beans.factory.BeanFactoryAware;
 import org.springframework.beans.factory.FactoryBean;
 import org.springframework.beans.factory.InitializingBean;
 import org.springframework.cloud.stream.annotation.EnableBinding;
@@ -45,10 +48,11 @@ import org.springframework.util.ReflectionUtils;
  * @author David Syer
  * @author Ilayaperumal Gopinathan
  * @author Oleg Zhurakousky
+ * @author Soby Chacko
  * @see EnableBinding
  */
 public class BindableProxyFactory extends AbstractBindableProxyFactory
-		implements MethodInterceptor, FactoryBean<Object>, InitializingBean {
+		implements MethodInterceptor, FactoryBean<Object>, InitializingBean, BeanFactoryAware {
 
 	private static Log log = LogFactory.getLog(BindableProxyFactory.class);
 
@@ -56,6 +60,8 @@ public class BindableProxyFactory extends AbstractBindableProxyFactory
 
 	private Object proxy;
 
+	private BeanFactory beanFactory;
+
 	public BindableProxyFactory(Class<?> type) {
 		super(type);
 		this.type = type;
@@ -112,6 +118,7 @@ public class BindableProxyFactory extends AbstractBindableProxyFactory
 
 	@Override
 	public void afterPropertiesSet() {
+		populateBindingTargetFactories(this.beanFactory);
 		Assert.notEmpty(BindableProxyFactory.this.bindingTargetFactories,
 				"'bindingTargetFactories' cannot be empty");
 		ReflectionUtils.doWithMethods(this.type, method -> {
@@ -159,4 +166,8 @@ public class BindableProxyFactory extends AbstractBindableProxyFactory
 		return true;
 	}
 
+	@Override
+	public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
+		this.beanFactory = beanFactory;
+	}
 }

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/BinderFactoryAutoConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2019 the original author or authors.
+ * Copyright 2015-2021 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.
@@ -170,6 +170,7 @@ public class BinderFactoryAutoConfiguration {
 		ClassLoader classLoader = configurableApplicationContext.getClassLoader();
 		try {
 			Enumeration<URL> resources = classLoader.getResources("META-INF/spring.binders");
+
 			// see if test binder is available on the classpath and if so add it to the binderTypes
 			try {
 				BinderType bt = new BinderType("integration", new Class[] {

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/config/BindingServiceConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2015-2018 the original author or authors.
+ * Copyright 2015-2021 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.
@@ -70,6 +70,7 @@ import org.springframework.messaging.MessageChannel;
 import org.springframework.messaging.core.DestinationResolver;
 import org.springframework.scheduling.TaskScheduler;
 import org.springframework.util.Assert;
+import org.springframework.util.CollectionUtils;
 import org.springframework.util.ObjectUtils;
 
 /**
@@ -198,7 +199,6 @@ public class BindingServiceConfiguration {
 	public BinderFactory binderFactory(BinderTypeRegistry binderTypeRegistry,
 			BindingServiceProperties bindingServiceProperties,
 			ObjectProvider<BinderCustomizer> binderCustomizerProvider) {
-
 		DefaultBinderFactory binderFactory = new DefaultBinderFactory(
 				getBinderConfigurations(binderTypeRegistry, bindingServiceProperties),
 				binderTypeRegistry, binderCustomizerProvider.getIfUnique());
@@ -271,11 +271,12 @@ public class BindingServiceConfiguration {
 	@Bean
 	@ConditionalOnMissingBean
 	public BinderAwareRouter binderAwareRouterBeanPostProcessor(
-			@Autowired(required = false) AbstractMappingMessageRouter[] routers,
+			@Autowired(required = false) List<AbstractMappingMessageRouter> routers,
 			@Autowired(required = false) @Qualifier("binderAwareChannelResolver")
 				DestinationResolver<MessageChannel> channelResolver) {
-
-		return new BinderAwareRouter(routers, channelResolver);
+		final AbstractMappingMessageRouter[] routersArray = CollectionUtils.isEmpty(routers) ?
+			new AbstractMappingMessageRouter[]{} : routers.toArray(new AbstractMappingMessageRouter[]{});
+		return new BinderAwareRouter(routersArray, channelResolver);
 	}
 
 	@Bean

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/BindableFunctionProxyFactory.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2019-2019 the original author or authors.
+ * Copyright 2019-2021 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.
@@ -39,6 +39,7 @@ import org.springframework.util.CollectionUtils;
  * function with the name `myFunction`.
  *
  * @author Oleg Zhurakousky
+ * @author Soby Chacko
  *
  * @since 3.0
  */
@@ -74,6 +75,7 @@ class BindableFunctionProxyFactory extends BindableProxyFactory {
 
 	@Override
 	public void afterPropertiesSet() {
+		populateBindingTargetFactories(context.getBeanFactory());
 		Assert.notEmpty(BindableFunctionProxyFactory.this.bindingTargetFactories,
 				"'bindingTargetFactories' cannot be empty");
 

spring-cloud-stream/src/main/java/org/springframework/cloud/stream/function/FunctionConfiguration.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2018-2020 the original author or authors.
+ * Copyright 2018-2021 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.
@@ -116,6 +116,7 @@ import org.springframework.util.StringUtils;
  * @author Oleg Zhurakousky
  * @author David Turanski
  * @author Ilayaperumal Gopinathan
+ * @author Soby Chacko
  * @since 2.1
  */
 @Configuration
@@ -147,10 +148,10 @@ public class FunctionConfiguration {
 	}
 
 	@Bean
-	public InitializingBean functionInitializer(FunctionCatalog functionCatalog, FunctionInspector functionInspector,
-			StreamFunctionProperties functionProperties, @Nullable BindableProxyFactory[] bindableProxyFactories,
-			BindingServiceProperties serviceProperties, ConfigurableApplicationContext applicationContext,
-			FunctionBindingRegistrar bindingHolder, StreamBridge streamBridge) {
+	public InitializingBean functionInitializer(FunctionCatalog functionCatalog,
+												StreamFunctionProperties functionProperties,
+												BindingServiceProperties serviceProperties, ConfigurableApplicationContext applicationContext,
+												StreamBridge streamBridge) {
 
 		boolean shouldCreateInitializer = applicationContext.containsBean("output")
 				|| ObjectUtils.isEmpty(applicationContext.getBeanNamesForAnnotation(EnableBinding.class));
@@ -167,10 +168,10 @@ public class FunctionConfiguration {
 	@Bean
 	InitializingBean supplierInitializer(FunctionCatalog functionCatalog, StreamFunctionProperties functionProperties,
 			GenericApplicationContext context, BindingServiceProperties serviceProperties,
-			@Nullable BindableFunctionProxyFactory[] proxyFactories, StreamBridge streamBridge,
+			@Nullable List<BindableFunctionProxyFactory> proxyFactories, StreamBridge streamBridge,
 			TaskScheduler taskScheduler) {
 
-		if (!ObjectUtils.isEmpty(context.getBeanNamesForAnnotation(EnableBinding.class)) || proxyFactories == null) {
+		if (!ObjectUtils.isEmpty(context.getBeanNamesForAnnotation(EnableBinding.class)) || CollectionUtils.isEmpty(proxyFactories)) {
 			return null;
 		}