DATAGEODE-119 - Check result type against function return type.

spring-data-geode/src/main/java/org/springframework/data/gemfire/function/execution/GemfireFunctionProxyFactoryBean.java

@@ -1,9 +1,5 @@
 /*
-<<<<<<< Updated upstream
  * Copyright 2002-2020 the original author or authors.
-=======
- * Copyright 2002-2020 the original author or authors.
->>>>>>> Stashed changes
  *
  * 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
@@ -17,6 +13,7 @@
 package org.springframework.data.gemfire.function.execution;
 
 import java.lang.reflect.Method;
+import java.util.stream.StreamSupport;
 
 import org.aopalliance.intercept.MethodInterceptor;
 import org.aopalliance.intercept.MethodInvocation;
@@ -35,6 +32,7 @@ import org.springframework.util.ClassUtils;
  *
  * @author David Turanski
  * @author John Blum
+ * @author Patrick Johnson
  * @see java.lang.reflect.Method
  * @see org.aopalliance.intercept.MethodInterceptor
  * @see org.springframework.beans.factory.BeanClassLoaderAware
@@ -93,7 +91,16 @@ public class GemfireFunctionProxyFactoryBean implements BeanClassLoaderAware, Fa
 			logger.debug("Invoking method {}", invocation.getMethod().getName());
 		}
 
-		return invokeFunction(invocation.getMethod(), invocation.getArguments());
+		Object result = invokeFunction(invocation.getMethod(), invocation.getArguments());
+
+		if(!invocation.getMethod().getReturnType().isAssignableFrom(result.getClass()) && result instanceof Iterable) {
+			Iterable iter = (Iterable)result;
+			if(StreamSupport.stream(iter.spliterator(), false).count() == 1) {
+				result = iter.iterator().next();
+			}
+		}
+
+		return result;
 	}
 
 	protected Object invokeFunction(Method method, Object[] args) {

spring-data-geode/src/test/java/org/springframework/data/gemfire/function/result/FunctionResultTypeIntegrationTest.java

@@ -0,0 +1,164 @@
+/*
+ * Copyright 2002-2020 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
+ *
+ * https://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.data.gemfire.function.result;
+
+import org.apache.geode.cache.DataPolicy;
+import org.apache.geode.cache.GemFireCache;
+import org.apache.geode.cache.client.ClientRegionShortcut;
+import org.junit.AfterClass;
+import org.junit.BeforeClass;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.context.annotation.AnnotationConfigApplicationContext;
+import org.springframework.context.annotation.Bean;
+import org.springframework.data.gemfire.ReplicatedRegionFactoryBean;
+import org.springframework.data.gemfire.client.ClientRegionFactoryBean;
+import org.springframework.data.gemfire.config.annotation.CacheServerApplication;
+import org.springframework.data.gemfire.config.annotation.ClientCacheApplication;
+import org.springframework.data.gemfire.function.annotation.FunctionId;
+import org.springframework.data.gemfire.function.annotation.GemfireFunction;
+import org.springframework.data.gemfire.function.annotation.OnRegion;
+import org.springframework.data.gemfire.function.config.EnableGemfireFunctionExecutions;
+import org.springframework.data.gemfire.function.config.EnableGemfireFunctions;
+import org.springframework.data.gemfire.process.ProcessWrapper;
+import org.springframework.data.gemfire.test.support.ClientServerIntegrationTestsSupport;
+import org.springframework.data.gemfire.transaction.config.EnableGemfireCacheTransactions;
+import org.springframework.test.context.ContextConfiguration;
+import org.springframework.test.context.junit4.SpringRunner;
+
+import java.io.IOException;
+import java.math.BigDecimal;
+import java.util.Collections;
+import java.util.List;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Patrick Johnson
+ */
+@RunWith(SpringRunner.class)
+@ContextConfiguration(classes = FunctionResultTypeIntegrationTest.FunctionInvocationClientApplicationConfig.class)
+public class FunctionResultTypeIntegrationTest extends ClientServerIntegrationTestsSupport {
+
+	private static ProcessWrapper server;
+
+	@Autowired
+	private FunctionExecutions functionExecutions;
+
+	@BeforeClass
+	public static void startServer() throws IOException {
+
+		final String GEMFIRE_LOCALHOST_PORT = "localhost[%d]";
+
+		int availablePort = findAvailablePort();
+
+		System.setProperty(GEMFIRE_CACHE_SERVER_PORT_PROPERTY, String.valueOf(availablePort));
+		System.setProperty(GEMFIRE_POOL_SERVERS_PROPERTY, String.format(GEMFIRE_LOCALHOST_PORT, availablePort));
+
+		server = run(FunctionServerApplicationConfig.class,
+				String.format("-D%s=%d", GEMFIRE_CACHE_SERVER_PORT_PROPERTY, availablePort));
+
+		waitForServerToStart(DEFAULT_HOSTNAME, availablePort);
+	}
+
+	@AfterClass
+	public static void stopServer() {
+		server.stop();
+		server = null;
+	}
+
+	@Test
+	public void singleResultFunctionsExecuteCorrectly() {
+		BigDecimal num = functionExecutions.returnFive();
+		assertThat(num.doubleValue()).isEqualTo(5);
+	}
+
+	@Test
+	public void listResultFunctionsExecuteCorrectly() {
+		List<BigDecimal> list = functionExecutions.returnList();
+		assertThat(list.size()).isEqualTo(1);
+	}
+
+	@Test
+	public void primitiveResultFunctionsExecuteCorrectly() {
+		int num = functionExecutions.returnPrimitive();
+		assertThat(num).isEqualTo(7);
+	}
+
+	@EnableGemfireFunctionExecutions(basePackageClasses = FunctionExecutions.class)
+	@ClientCacheApplication(name = "SingleResultFunctionExecutionTest")
+	@EnableGemfireCacheTransactions
+	public static class FunctionInvocationClientApplicationConfig {
+
+		@Bean("Numbers")
+		protected ClientRegionFactoryBean<Long, BigDecimal> configureProxyClientNumberRegion(GemFireCache gemFireCache) {
+			ClientRegionFactoryBean<Long, BigDecimal> clientRegionFactoryBean = new ClientRegionFactoryBean<>();
+			clientRegionFactoryBean.setCache(gemFireCache);
+			clientRegionFactoryBean.setName("Numbers");
+			clientRegionFactoryBean.setShortcut(ClientRegionShortcut.PROXY);
+			return clientRegionFactoryBean;
+		}
+	}
+
+	@EnableGemfireFunctions
+	@CacheServerApplication(name = "SingleResultFunctionExecutionTestServer")
+	public static class FunctionServerApplicationConfig {
+
+		public static void main(String[] args) {
+
+			AnnotationConfigApplicationContext applicationContext =
+					new AnnotationConfigApplicationContext(FunctionServerApplicationConfig.class);
+
+			applicationContext.registerShutdownHook();
+		}
+
+		@Bean
+		ReplicatedRegionFactoryBean<Long, BigDecimal> createNumberRegion(GemFireCache gemfireCache) {
+			ReplicatedRegionFactoryBean replicatedRegionFactoryBean = new ReplicatedRegionFactoryBean();
+			replicatedRegionFactoryBean.setCache(gemfireCache);
+			replicatedRegionFactoryBean.setRegionName("Numbers");
+			replicatedRegionFactoryBean.setDataPolicy(DataPolicy.REPLICATE);
+			return replicatedRegionFactoryBean;
+		}
+
+		@GemfireFunction(id = "returnSingleObject", hasResult = true)
+		public BigDecimal returnSingleObject() {
+			return new BigDecimal(5);
+		}
+
+		@GemfireFunction(id = "returnList", hasResult = true)
+		public List<BigDecimal> returnList() {
+			return Collections.singletonList(new BigDecimal(10));
+		}
+
+		@GemfireFunction(id = "returnPrimitive", hasResult = true)
+		public int returnPrimitive() {
+			return 7;
+		}
+	}
+}
+
+@OnRegion(region = "Numbers")
+interface FunctionExecutions {
+
+	@FunctionId("returnSingleObject")
+	BigDecimal returnFive();
+
+	@FunctionId("returnList")
+	List<BigDecimal> returnList();
+
+	@FunctionId("returnPrimitive")
+	int returnPrimitive();
+}