Merge pull request #117 from aclement/SPR-9621

* SPR-9621:
  Avoid NPE when registering a SpEL MethodFilter

spring-expression/src/main/java/org/springframework/expression/spel/support/StandardEvaluationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2011 the original author or authors.
+ * 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.
@@ -43,6 +43,7 @@ import org.springframework.util.Assert;
  *
  * @author Andy Clement
  * @author Juergen Hoeller
+ * @author Sam Brannen
  * @since 3.0
  */
 public class StandardEvaluationContext implements EvaluationContext {
@@ -218,16 +219,23 @@ public class StandardEvaluationContext implements EvaluationContext {
 	}
 
 	/**
-	 * Register a MethodFilter which will be called during method resolution for the
-	 * specified type.  The MethodFilter may remove methods and/or sort the methods
-	 * which will then be used by SpEL as the candidates to look through for a match.
+	 * Register a {@code MethodFilter} which will be called during method resolution
+	 * for the specified type.
+	 *
+	 * <p>The {@code MethodFilter} may remove methods and/or sort the methods which
+	 * will then be used by SpEL as the candidates to look through for a match.
 	 *
 	 * @param type the type for which the filter should be called
-	 * @param filter a MethodFilter, or NULL to deregister a filter for the type
+	 * @param filter a {@code MethodFilter}, or {@code null} to unregister a filter for the type
+	 * @throws IllegalStateException if the {@link ReflectiveMethodResolver} is not in use
 	 */
-	public void registerMethodFilter(Class<?> type, MethodFilter filter) {
+	public void registerMethodFilter(Class<?> type, MethodFilter filter) throws IllegalStateException {
 		ensureMethodResolversInitialized();
-		reflectiveMethodResolver.registerMethodFilter(type,filter);
+		if (reflectiveMethodResolver != null) {
+			reflectiveMethodResolver.registerMethodFilter(type, filter);
+		} else {
+			throw new IllegalStateException("Method filter cannot be set as the reflective method resolver is not in use");
+		}
 	}
 
 	private void ensurePropertyAccessorsInitialized() {

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

@@ -18,15 +18,22 @@ package org.springframework.expression.spel;
 
 import static org.junit.Assert.*;
 
+import java.lang.reflect.Method;
+import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
 
 import org.junit.Test;
 
+import org.springframework.core.convert.TypeDescriptor;
+import org.springframework.expression.AccessException;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.EvaluationException;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ExpressionParser;
+import org.springframework.expression.MethodExecutor;
+import org.springframework.expression.MethodFilter;
+import org.springframework.expression.MethodResolver;
 import org.springframework.expression.ParseException;
 import org.springframework.expression.spel.standard.SpelExpression;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
@@ -98,8 +105,8 @@ public class EvaluationTests extends ExpressionTestCase {
 	}
 
 
+	@SuppressWarnings("rawtypes")
 	static class TestClass {
-
 		public Foo wibble;
 		private Foo wibble2;
 		public Map map;
@@ -571,4 +578,48 @@ public class EvaluationTests extends ExpressionTestCase {
 		assertNull(exp.getValue());
 	}
 
+	/**
+	 * Verifies behavior requested in SPR-9621.
+	 */
+	@Test
+	public void customMethodFilter() throws Exception {
+		StandardEvaluationContext context = new StandardEvaluationContext();
+
+		// Register a custom MethodResolver...
+		List<MethodResolver> customResolvers = new ArrayList<MethodResolver>();
+		customResolvers.add(new CustomMethodResolver());
+		context.setMethodResolvers(customResolvers);
+
+		// or simply...
+		// context.setMethodResolvers(new ArrayList<MethodResolver>());
+
+		// Register a custom MethodFilter...
+		MethodFilter filter = new CustomMethodFilter();
+		try {
+			context.registerMethodFilter(String.class, filter);
+			fail("should have failed");
+		} catch (IllegalStateException ise) {
+			assertEquals(
+					"Method filter cannot be set as the reflective method resolver is not in use",
+					ise.getMessage());
+		}
+	}
+
+	static class CustomMethodResolver implements MethodResolver {
+
+		public MethodExecutor resolve(EvaluationContext context,
+				Object targetObject, String name,
+				List<TypeDescriptor> argumentTypes) throws AccessException {
+			return null;
+		}
+	}
+
+	static class CustomMethodFilter implements MethodFilter {
+
+		public List<Method> filter(List<Method> methods) {
+			return null;
+		}
+
+	}
+
 }

src/dist/changelog.txt

@@ -9,9 +9,10 @@ Changes in version 3.2 M2 (2012-08-xx)
 * spring-test module now depends on junit:junit-dep (SPR-6966)
 * now inferring return type of generic factory methods (SPR-9493)
 * SpEL now supports method invocations on integers (SPR-9612)
+* SpEL now supports case-insensitive null literals in expressions (SPR-9613)
 * SpEL now supports symbolic boolean operators for OR and AND (SPR-9614)
 * SpEL now supports nested double quotes in expressions (SPR-9620)
-* introduced support for case-insensitive null literals in SpEL expressions (SPR-9613)
+* SpEL now throws an ISE if a MethodFilter is registered against custom resolvers (SPR-9621)
 * now using BufferedInputStream in SimpleMetaDataReader to double performance (SPR-9528)
 * introduced "repeatCount" property in Quartz SimpleTriggerFactoryBean (SPR-9521)
 * introduced "jtaTransactionManager" property in Hibernate 4 LocalSessionFactoryBean/Builder (SPR-9480)