avoid duplicate linkage errors

spring-cloud-function-core/src/main/java/org/springframework/cloud/function/registry/AbstractFunctionRegistry.java

@@ -16,6 +16,8 @@
 
 package org.springframework.cloud.function.registry;
 
+import java.util.HashMap;
+import java.util.Map;
 import java.util.function.Function;
 
 import org.springframework.cloud.function.compiler.CompiledFunctionFactory;
@@ -27,11 +29,13 @@ import org.springframework.util.Assert;
 /**
  * @author Mark Fisher
  */
-public abstract class FunctionRegistrySupport implements FunctionRegistry {
+public abstract class AbstractFunctionRegistry implements FunctionRegistry {
+
+	private static final Map<String, FunctionFactory<?, ?>> FACTORY_CACHE = new HashMap<>();
 
 	private final FunctionCompiler compiler = new FunctionCompiler();
 
-	private final SimpleClassLoader classLoader = new SimpleClassLoader(FunctionRegistrySupport.class.getClassLoader());
+	private final SimpleClassLoader classLoader = new SimpleClassLoader(AbstractFunctionRegistry.class.getClassLoader());
 
 	@Override
 	@SuppressWarnings("unchecked")
@@ -44,19 +48,33 @@ public abstract class FunctionRegistrySupport implements FunctionRegistry {
 		return function;
 	}
 
+	@Override
+	public final <T, R> Function<T, R> lookup(String name) {
+		@SuppressWarnings("unchecked")
+		FunctionFactory<T, R> factory = (FunctionFactory<T, R>) FACTORY_CACHE.get(name);
+		if (factory != null) {
+			return factory.getFunction();
+		}
+		return this.doLookup(name);
+	}
+
+	protected abstract <T, R> Function<T, R> doLookup(String name);
+
 	protected <T, R> CompiledFunctionFactory<T, R> compile(String name, String code) {
 		return this.compiler.compile(name, code);
 	}
 
 	@SuppressWarnings("unchecked")
-	protected <T, R> Function<T, R> deserialize(String name, byte[] bytes) {
+	protected <T, R> Function<T, R> deserialize(final String name, byte[] bytes) {
 		Assert.hasLength(name, "name must not be empty");
 		String firstLetter = name.substring(0, 1).toUpperCase();
-		name = (name.length() > 1) ? firstLetter + name.substring(1) : firstLetter;
-		String className = String.format("%s.%sFunctionFactory", FunctionCompiler.class.getPackage().getName(), name); 
+		String upperCasedName = (name.length() > 1) ? firstLetter + name.substring(1) : firstLetter;
+		String className = String.format("%s.%sFunctionFactory", FunctionCompiler.class.getPackage().getName(), upperCasedName); 
 		Class<?> factoryClass = this.classLoader.defineClass(className, bytes);
 		try {
-			return ((FunctionFactory<T, R>) factoryClass.newInstance()).getFunction();
+			FunctionFactory<T, R> factory = ((FunctionFactory<T, R>) factoryClass.newInstance());
+			FACTORY_CACHE.put(name, factory);
+			return factory.getFunction();
 		}
 		catch (InstantiationException | IllegalAccessException e) {
 			throw new IllegalArgumentException("failed to deserialize function", e);

spring-cloud-function-core/src/main/java/org/springframework/cloud/function/registry/FileSystemFunctionRegistry.java

@@ -27,7 +27,7 @@ import org.springframework.util.FileCopyUtils;
 /**
  * @author Mark Fisher
  */
-public class FileSystemFunctionRegistry extends FunctionRegistrySupport {
+public class FileSystemFunctionRegistry extends AbstractFunctionRegistry {
 
 	private final File directory;
 
@@ -48,7 +48,7 @@ public class FileSystemFunctionRegistry extends FunctionRegistrySupport {
 	}
 
 	@Override
-	public <T, R> Function<T, R> lookup(String name) {
+	public <T, R> Function<T, R> doLookup(String name) {
 		try {
 			byte[] bytes = FileCopyUtils.copyToByteArray(new File(this.directory, fileName(name)));
 			return this.deserialize(name, bytes);

spring-cloud-function-core/src/main/java/org/springframework/cloud/function/registry/InMemoryFunctionRegistry.java

@@ -22,13 +22,13 @@ import java.util.function.Function;
 /**
  * @author Mark Fisher
  */
-public class InMemoryFunctionRegistry extends FunctionRegistrySupport {
+public class InMemoryFunctionRegistry extends AbstractFunctionRegistry {
 
 	private final ConcurrentHashMap<String, Function<?, ?>> map = new ConcurrentHashMap<>();
 
 	@Override
 	@SuppressWarnings("unchecked")
-	public Function<?, ?> lookup(String name) {
+	public Function<?, ?> doLookup(String name) {
 		return this.map.get(name);
 	}
 

spring-cloud-function-core/src/test/java/org/springframework/cloud/function/gateway/LocalFunctionGatewayTests.java

@@ -0,0 +1,61 @@
+/*
+ * Copyright 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.cloud.function.gateway;
+
+import static org.junit.Assert.assertEquals;
+
+import java.util.List;
+
+import org.junit.Before;
+import org.junit.Test;
+
+import org.springframework.cloud.function.registry.FileSystemFunctionRegistry;
+import org.springframework.cloud.function.registry.FunctionRegistry;
+import org.springframework.scheduling.concurrent.ThreadPoolTaskScheduler;
+
+import reactor.core.publisher.Flux;
+
+/**
+ * @author Mark Fisher
+ */
+public class LocalFunctionGatewayTests {
+
+	private final FunctionRegistry registry = new FileSystemFunctionRegistry();
+
+	private final ThreadPoolTaskScheduler scheduler = new ThreadPoolTaskScheduler();
+
+	@Before
+	public void init() {
+		this.scheduler.initialize();
+	}
+
+	@Test
+	public void test() {
+		LocalFunctionGateway gateway = new LocalFunctionGateway(registry, scheduler);
+		Flux<String> output = gateway.invoke("uppercase", Flux.just("foo", "bar"));
+		List<String> results = output.collectList().block();
+		assertEquals("FOO", results.get(0));
+		assertEquals("BAR", results.get(1));
+	}
+
+	@Test
+	public void testMultiple() {
+		for (int i = 0; i < 100; i++) {
+			test();
+		}
+	}
+}