Include argument types in MethodReference cache

Update the cached MethodExecutor in MethodReference to include the
method argument types. Prevents the incorrect use of the cache when the
SpEL expression refers to a class that has overloaded methods.

Issue: SPR-10657

spring-expression/src/main/java/org/springframework/expression/spel/ast/MethodReference.java

@@ -18,6 +18,7 @@ package org.springframework.expression.spel.ast;
 
 import java.lang.reflect.InvocationTargetException;
 import java.util.ArrayList;
+import java.util.Collections;
 import java.util.List;
 
 import org.springframework.core.convert.TypeDescriptor;
@@ -45,7 +46,7 @@ public class MethodReference extends SpelNodeImpl {
 
 	private final boolean nullSafe;
 
-	private volatile MethodExecutor cachedExecutor;
+	private volatile CachedMethodExecutor cachedExecutor;
 
 
 	public MethodReference(boolean nullSafe, String methodName, int pos, SpelNodeImpl... arguments) {
@@ -101,17 +102,18 @@ public class MethodReference extends SpelNodeImpl {
 				state.popActiveContextObject();
 			}
 		}
+		List<TypeDescriptor> argumentTypes = getTypes(arguments);
 		if (currentContext.getValue() == null) {
 			if (this.nullSafe) {
 				return TypedValue.NULL;
 			}
 			else {
 				throw new SpelEvaluationException(getStartPosition(), SpelMessage.METHOD_CALL_ON_NULL_OBJECT_NOT_ALLOWED,
-						FormatHelper.formatMethodForMessage(this.name, getTypes(arguments)));
+						FormatHelper.formatMethodForMessage(this.name, argumentTypes));
 			}
 		}
 
-		MethodExecutor executorToUse = this.cachedExecutor;
+		MethodExecutor executorToUse = getCachedExecutor(argumentTypes);
 		if (executorToUse != null) {
 			try {
 				return executorToUse.execute(state.getEvaluationContext(),
@@ -136,8 +138,8 @@ public class MethodReference extends SpelNodeImpl {
 		}
 
 		// either there was no accessor or it no longer existed
-		executorToUse = findAccessorForMethod(this.name, getTypes(arguments), state);
-		this.cachedExecutor = executorToUse;
+		executorToUse = findAccessorForMethod(this.name, argumentTypes, state);
+		this.cachedExecutor = new CachedMethodExecutor(executorToUse, argumentTypes);
 		try {
 			return executorToUse.execute(state.getEvaluationContext(),
 					state.getActiveContextObject().getValue(), arguments);
@@ -172,7 +174,7 @@ public class MethodReference extends SpelNodeImpl {
 		for (Object argument : arguments) {
 			descriptors.add(TypeDescriptor.forObject(argument));
 		}
-		return descriptors;
+		return Collections.unmodifiableList(descriptors);
 	}
 
 	@Override
@@ -225,6 +227,14 @@ public class MethodReference extends SpelNodeImpl {
 						: contextObject.getClass()));
 	}
 
+	private MethodExecutor getCachedExecutor(List<TypeDescriptor> argumentTypes) {
+		if (this.cachedExecutor == null || !this.cachedExecutor.isSuitable(argumentTypes)) {
+			this.cachedExecutor = null;
+			return null;
+		}
+		return this.cachedExecutor.get();
+	}
+
 
 	private class MethodValueRef implements ValueRef {
 
@@ -236,18 +246,21 @@ public class MethodReference extends SpelNodeImpl {
 
 		private final Object[] arguments;
 
+		private List<TypeDescriptor> argumentTypes;
+
 
 		MethodValueRef(ExpressionState state, EvaluationContext evaluationContext, Object object, Object[] arguments) {
 			this.state = state;
 			this.evaluationContext = evaluationContext;
 			this.target = object;
 			this.arguments = arguments;
+			this.argumentTypes = getTypes(this.arguments);
 		}
 
 
 		@Override
 		public TypedValue getValue() {
-			MethodExecutor executorToUse = MethodReference.this.cachedExecutor;
+			MethodExecutor executorToUse = getCachedExecutor(this.argumentTypes);
 			if (executorToUse != null) {
 				try {
 					return executorToUse.execute(this.evaluationContext, this.target, this.arguments);
@@ -271,8 +284,8 @@ public class MethodReference extends SpelNodeImpl {
 			}
 
 			// either there was no accessor or it no longer existed
-			executorToUse = findAccessorForMethod(MethodReference.this.name, getTypes(this.arguments), this.target, this.evaluationContext);
-			MethodReference.this.cachedExecutor = executorToUse;
+			executorToUse = findAccessorForMethod(MethodReference.this.name, argumentTypes, this.target, this.evaluationContext);
+			MethodReference.this.cachedExecutor = new CachedMethodExecutor(executorToUse, this.argumentTypes);
 			try {
 				return executorToUse.execute(this.evaluationContext, this.target, this.arguments);
 			}
@@ -297,4 +310,27 @@ public class MethodReference extends SpelNodeImpl {
 		}
 	}
 
+
+	private static class CachedMethodExecutor {
+
+		private final MethodExecutor methodExecutor;
+
+		private final List<TypeDescriptor> argumentTypes;
+
+
+		public CachedMethodExecutor(MethodExecutor methodExecutor,
+				List<TypeDescriptor> argumentTypes) {
+			this.methodExecutor = methodExecutor;
+			this.argumentTypes = argumentTypes;
+		}
+
+
+		public boolean isSuitable(List<TypeDescriptor> argumentTypes) {
+			return (this.methodExecutor != null && this.argumentTypes.equals(argumentTypes));
+		}
+
+		public MethodExecutor get() {
+			return this.methodExecutor;
+		}
+	}
 }

spring-expression/src/test/java/org/springframework/expression/spel/CachedMethodExecutorTests.java

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2002-2012 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.expression.spel;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.springframework.expression.Expression;
+import org.springframework.expression.ExpressionParser;
+import org.springframework.expression.spel.ast.MethodReference;
+import org.springframework.expression.spel.standard.SpelExpressionParser;
+import org.springframework.expression.spel.support.StandardEvaluationContext;
+
+import static org.junit.Assert.*;
+
+/**
+ * Test for caching in {@link MethodReference} (SPR-10657).
+ *
+ * @author Oliver Becker
+ */
+public class CachedMethodExecutorTests {
+
+	private final ExpressionParser parser = new SpelExpressionParser();
+
+	private StandardEvaluationContext context;
+
+
+	@Before
+	public void setUp() throws Exception {
+		this.context = new StandardEvaluationContext(new RootObject());
+	}
+
+
+	@Test
+	public void testCachedExecution() throws Exception {
+		Expression expression = this.parser.parseExpression("echo(#something)");
+
+		assertMethodExecution(expression, 42, "int: 42");
+		assertMethodExecution(expression, 42, "int: 42");
+		assertMethodExecution(expression, "Deep Thought", "String: Deep Thought");
+		assertMethodExecution(expression, 42, "int: 42");
+	}
+
+	private void assertMethodExecution(Expression expression, Object var, String expected) {
+		this.context.setVariable("something", var);
+		assertEquals(expected, expression.getValue(this.context));
+	}
+
+
+	public static class RootObject {
+
+		public String echo(String value) {
+			return "String: " + value;
+		}
+
+		public String echo(int value) {
+			return "int: " + value;
+		}
+
+	}
+
+}