added FunctionProxyApplicationListener

added support for lambda compiling Supplier and Consumer proxies

spring-cloud-function-compiler/src/main/java/org/springframework/cloud/function/compiler/config/FunctionProxyApplicationListener.java

@@ -0,0 +1,115 @@
+/*
+ * Copyright 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.compiler.config;
+
+import java.util.Map;
+
+import org.springframework.beans.factory.config.ConstructorArgumentValues;
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.beans.factory.support.RootBeanDefinition;
+import org.springframework.boot.bind.PropertySourcesBinder;
+import org.springframework.boot.context.event.ApplicationPreparedEvent;
+import org.springframework.cloud.function.compiler.ConsumerCompiler;
+import org.springframework.cloud.function.compiler.FunctionCompiler;
+import org.springframework.cloud.function.compiler.SupplierCompiler;
+import org.springframework.cloud.function.compiler.proxy.ByteCodeLoadingConsumer;
+import org.springframework.cloud.function.compiler.proxy.ByteCodeLoadingFunction;
+import org.springframework.cloud.function.compiler.proxy.ByteCodeLoadingSupplier;
+import org.springframework.cloud.function.compiler.proxy.LambdaCompilingConsumer;
+import org.springframework.cloud.function.compiler.proxy.LambdaCompilingFunction;
+import org.springframework.cloud.function.compiler.proxy.LambdaCompilingSupplier;
+import org.springframework.context.ApplicationListener;
+import org.springframework.context.ConfigurableApplicationContext;
+import org.springframework.core.io.ByteArrayResource;
+import org.springframework.core.io.Resource;
+
+/**
+ * @author Mark Fisher
+ */
+public class FunctionProxyApplicationListener implements ApplicationListener<ApplicationPreparedEvent> {
+
+	private final SupplierCompiler<?> supplierCompiler = new SupplierCompiler<>();
+
+	private final FunctionCompiler<?, ?> functionCompiler = new FunctionCompiler<>();
+
+	private final ConsumerCompiler<?> consumerCompiler = new ConsumerCompiler<>();
+
+	@Override
+	public void onApplicationEvent(ApplicationPreparedEvent event) {
+		ConfigurableApplicationContext context = event.getApplicationContext();
+		DefaultListableBeanFactory beanFactory = (DefaultListableBeanFactory) context.getBeanFactory();
+		PropertySourcesBinder binder = new PropertySourcesBinder(context.getEnvironment());
+		Map<String, Object> extracted = binder.extractAll("spring.cloud.function.proxy");
+		for (Map.Entry<String, Object> entry : extracted.entrySet()) {
+			String name = entry.getKey();
+			@SuppressWarnings("unchecked")
+			Map<String, String> properties = (Map<String, String>) entry.getValue();
+			String type = (properties.get("type") != null) ? properties.get("type") : "function";
+			String resource = properties.get("resource");
+			String lambda = properties.get("lambda");
+			if (!(null == resource ^ null == lambda)) {
+				throw new IllegalArgumentException("Exactly one of 'resource' or 'lambda' is required for a Function proxy");
+			}
+			if (resource != null) {
+				registerByteCodeLoadingProxy(name, type, context.getResource(resource), beanFactory);
+			}
+			else {
+				registerLambdaCompilingProxy(name, type, lambda, beanFactory);
+			}
+		}
+	}
+
+	private void registerByteCodeLoadingProxy(String name, String type, Resource resource, DefaultListableBeanFactory beanFactory) {
+		Class<?> proxyClass = null;
+		if ("supplier".equals(type.toLowerCase())) {
+			proxyClass = ByteCodeLoadingSupplier.class;
+		}
+		else if ("consumer".equals(type.toLowerCase())) {
+			proxyClass = ByteCodeLoadingConsumer.class;
+		}
+		else {
+			proxyClass = ByteCodeLoadingFunction.class;
+		}
+		RootBeanDefinition beanDefinition = new RootBeanDefinition(proxyClass);
+		ConstructorArgumentValues args = new ConstructorArgumentValues();
+		args.addGenericArgumentValue(resource);
+		beanDefinition.setConstructorArgumentValues(args);
+		beanFactory.registerBeanDefinition(name, beanDefinition);
+	}
+
+	private void registerLambdaCompilingProxy(String name, String type, String lambda, DefaultListableBeanFactory beanFactory) {
+		Resource resource = new ByteArrayResource(lambda.getBytes());
+		ConstructorArgumentValues args = new ConstructorArgumentValues();
+		args.addGenericArgumentValue(resource);
+		Class<?> proxyClass = null;
+		if ("supplier".equals(type.toLowerCase())) {
+			proxyClass = LambdaCompilingSupplier.class;
+			args.addGenericArgumentValue(this.supplierCompiler);
+		}
+		else if ("consumer".equals(type.toLowerCase())) {
+			proxyClass = LambdaCompilingConsumer.class;
+			args.addGenericArgumentValue(this.consumerCompiler);
+		}
+		else {
+			proxyClass = LambdaCompilingFunction.class;
+			args.addGenericArgumentValue(this.functionCompiler);
+		}
+		RootBeanDefinition beanDefinition = new RootBeanDefinition(proxyClass);
+		beanDefinition.setConstructorArgumentValues(args);
+		beanFactory.registerBeanDefinition(name, beanDefinition);
+	}
+}

spring-cloud-function-compiler/src/main/resources/META-INF/spring.factories

@@ -0,0 +1,2 @@
+org.springframework.context.ApplicationListener=\
+org.springframework.cloud.function.compiler.config.FunctionProxyApplicationListener