From 2bd1afdb9e2982d355528a0a2fa99003e1178739 Mon Sep 17 00:00:00 2001
From: John Blum <jblum@pivotal.io>
Date: Wed, 29 Aug 2018 10:06:33 -0700
Subject: [PATCH] Add utiliy method to invoke a method on an object.

---
 .../geode/core/util/ObjectUtils.java          | 33 +++++++++++++++++++
 .../geode/core/util/ObjectUtilsUnitTests.java | 29 ++++++++++++++++
 2 files changed, 62 insertions(+)

diff --git a/spring-geode/src/main/java/org/springframework/geode/core/util/ObjectUtils.java b/spring-geode/src/main/java/org/springframework/geode/core/util/ObjectUtils.java
index ced604b4..5241af8e 100644
--- a/spring-geode/src/main/java/org/springframework/geode/core/util/ObjectUtils.java
+++ b/spring-geode/src/main/java/org/springframework/geode/core/util/ObjectUtils.java
@@ -19,15 +19,20 @@ package org.springframework.geode.core.util;
 import static org.springframework.data.gemfire.util.RuntimeExceptionFactory.newIllegalArgumentException;
 import static org.springframework.data.gemfire.util.RuntimeExceptionFactory.newIllegalStateException;
 
+import java.lang.reflect.Method;
+import java.util.Optional;
+
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 import org.springframework.lang.Nullable;
+import org.springframework.util.ReflectionUtils;
 
 /**
  * The {@link ObjectUtils} class is an abstract utility class with operations for {@link Object objects}.
  *
  * @author John Blum
  * @see java.lang.Object
+ * @see java.lang.reflect.Method
  * @since 1.0.0
  */
 @SuppressWarnings("all")
@@ -85,6 +90,34 @@ public abstract class ObjectUtils extends org.springframework.util.ObjectUtils {
 		}
 	}
 
+	/**
+	 * Invokes a {@link Method} on an {@link Object} with the given {@link String name}.
+	 *
+	 * @param <T> {@link Class type} of the {@link Method} return value.
+	 * @param obj {@link Object} on which to invoke the {@link Method}.
+	 * @param methodName {@link String} containing the name of the {@link Method} to invoke on {@link Object}.
+	 * @return the return value of the invoked {@link Method} on {@link Object}.
+	 * @throws IllegalArgumentException if no {@link Method} with {@link String name} could be found on {@link Object}.
+	 * @see java.lang.reflect.Method
+	 * @see java.lang.Object
+	 */
+	@SuppressWarnings("unchecked")
+	public static <T> T invoke(Object obj, String methodName) {
+
+		return (T) Optional.ofNullable(obj)
+			.map(Object::getClass)
+			.map(type -> ReflectionUtils.findMethod(type, methodName))
+			.map(ObjectUtils::makeAccessible)
+			.map(method -> ReflectionUtils.invokeMethod(method, obj))
+			.orElseThrow(() -> newIllegalArgumentException("Method [%1$s] on Object of type [%2$s] not found",
+				methodName, org.springframework.util.ObjectUtils.nullSafeClassName(obj)));
+	}
+
+	private static Method makeAccessible(Method method) {
+		ReflectionUtils.makeAccessible(method);
+		return method;
+	}
+
 	/**
 	 * Returns the given {@link Object value} or throws an {@link IllegalArgumentException}
 	 * if {@link Object value} is {@literal null}.
diff --git a/spring-geode/src/test/java/org/springframework/geode/core/util/ObjectUtilsUnitTests.java b/spring-geode/src/test/java/org/springframework/geode/core/util/ObjectUtilsUnitTests.java
index c4ca24d6..3ccfc25e 100644
--- a/spring-geode/src/test/java/org/springframework/geode/core/util/ObjectUtilsUnitTests.java
+++ b/spring-geode/src/test/java/org/springframework/geode/core/util/ObjectUtilsUnitTests.java
@@ -59,6 +59,28 @@ public class ObjectUtilsUnitTests {
 		}
 	}
 
+	@Test
+	public void invokeMethodOnObjectReturnsValue() {
+		assertThat(ObjectUtils.<String>invoke(new TestObject(), "testMethod")).isEqualTo("TEST");
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void invokeNonExistingMethodOnObjectThrowsIllegalArgumentException() {
+
+		try {
+			ObjectUtils.invoke(new TestObject(), "nonExistingMethod");
+		}
+		catch (IllegalArgumentException expected) {
+
+			assertThat(expected).hasMessage("Method [nonExistingMethod] on Object of type [%s] not found",
+				TestObject.class.getName());
+
+			assertThat(expected).hasNoCause();
+
+			throw expected;
+		}
+	}
+
 	@Test
 	public void returnValueThrowOnNullWithNonNullValueReturnsValue() {
 		assertThat(ObjectUtils.returnValueThrowOnNull("test")).isEqualTo("test");
@@ -78,4 +100,11 @@ public class ObjectUtilsUnitTests {
 			throw expected;
 		}
 	}
+
+	public static class TestObject {
+
+		public String testMethod() {
+			return "TEST";
+		}
+	}
 }