Move cached expression evaluation abstraction

Move MethodCacheKey and related classes to the expression package so that
other parts of the framework can benefit ot it.

CacheExpressionEvaluator is a base class that can be used to cache SpEL
expressions based on its annotation source (i.e. method). Sub-classing
that base class provides a simple to use API to retrieve Expression
instances efficiently.

Issue: SPR-12622

Author: snicoll

spring-context-support/src/main/java/org/springframework/cache/jcache/interceptor/AbstractFallbackJCacheOperationSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -24,7 +24,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
-import org.springframework.cache.interceptor.MethodCacheKey;
+import org.springframework.context.expression.AnnotatedElementKey;
 import org.springframework.core.BridgeMethodResolver;
 import org.springframework.util.ClassUtils;
 
@@ -57,7 +57,7 @@ public abstract class AbstractFallbackJCacheOperationSource
 	@Override
 	public JCacheOperation<?> getCacheOperation(Method method, Class<?> targetClass) {
 		// First, see if we have a cached value.
-		Object cacheKey = new MethodCacheKey(method, targetClass);
+		Object cacheKey = new AnnotatedElementKey(method, targetClass);
 		Object cached = this.cache.get(cacheKey);
 		if (cached != null) {
 			if (cached == NULL_CACHING_ATTRIBUTE) {

spring-context/src/main/java/org/springframework/cache/interceptor/AbstractFallbackCacheOperationSource.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -26,6 +26,7 @@
 import org.apache.commons.logging.Log;
 import org.apache.commons.logging.LogFactory;
 
+import org.springframework.context.expression.AnnotatedElementKey;
 import org.springframework.core.BridgeMethodResolver;
 import org.springframework.util.ClassUtils;
 
@@ -121,7 +122,7 @@ public Collection<CacheOperation> getCacheOperations(Method method, Class<?> tar
 	 * @return the cache key (never {@code null})
 	 */
 	protected Object getCacheKey(Method method, Class<?> targetClass) {
-		return new MethodCacheKey(method, targetClass);
+		return new AnnotatedElementKey(method, targetClass);
 	}
 
 	private Collection<CacheOperation> computeCacheOperations(Method method, Class<?> targetClass) {

spring-context/src/main/java/org/springframework/cache/interceptor/CacheAspectSupport.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -39,6 +39,7 @@
 import org.springframework.cache.support.SimpleValueWrapper;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ApplicationContextAware;
+import org.springframework.context.expression.AnnotatedElementKey;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.util.Assert;
 import org.springframework.util.ClassUtils;
@@ -546,14 +547,14 @@ protected class CacheOperationContext implements CacheOperationInvocationContext
 
 		private final Collection<? extends Cache> caches;
 
-		private final MethodCacheKey methodCacheKey;
+		private final AnnotatedElementKey methodCacheKey;
 
 		public CacheOperationContext(CacheOperationMetadata metadata, Object[] args, Object target) {
 			this.metadata = metadata;
 			this.args = extractArgs(metadata.method, args);
 			this.target = target;
 			this.caches = CacheAspectSupport.this.getCaches(this, metadata.cacheResolver);
-			this.methodCacheKey = new MethodCacheKey(metadata.method, metadata.targetClass);
+			this.methodCacheKey = new AnnotatedElementKey(metadata.method, metadata.targetClass);
 		}
 
 		@Override
@@ -659,11 +660,11 @@ private static class CacheOperationCacheKey {
 
 		private final CacheOperation cacheOperation;
 
-		private final MethodCacheKey methodCacheKey;
+		private final AnnotatedElementKey methodCacheKey;
 
 		private CacheOperationCacheKey(CacheOperation cacheOperation, Method method, Class<?> targetClass) {
 			this.cacheOperation = cacheOperation;
-			this.methodCacheKey = new MethodCacheKey(method, targetClass);
+			this.methodCacheKey = new AnnotatedElementKey(method, targetClass);
 		}
 
 		@Override

spring-context/src/main/java/org/springframework/cache/interceptor/CacheEvaluationContext.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -22,6 +22,7 @@
 import java.util.Map;
 
 import org.springframework.aop.support.AopUtils;
+import org.springframework.context.expression.AnnotatedElementKey;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
 import org.springframework.util.ObjectUtils;
@@ -53,15 +54,15 @@ class CacheEvaluationContext extends StandardEvaluationContext {
 
 	private final Class<?> targetClass;
 
-	private final Map<MethodCacheKey, Method> methodCache;
+	private final Map<AnnotatedElementKey, Method> methodCache;
 
 	private final List<String> unavailableVariables;
 
 	private boolean paramLoaded = false;
 
 
 	CacheEvaluationContext(Object rootObject, ParameterNameDiscoverer paramDiscoverer, Method method,
-			Object[] args, Class<?> targetClass, Map<MethodCacheKey, Method> methodCache) {
+			Object[] args, Class<?> targetClass, Map<AnnotatedElementKey, Method> methodCache) {
 		super(rootObject);
 
 		this.paramDiscoverer = paramDiscoverer;
@@ -110,7 +111,7 @@ private void loadArgsAsVariables() {
 			return;
 		}
 
-		MethodCacheKey methodKey = new MethodCacheKey(this.method, this.targetClass);
+		AnnotatedElementKey methodKey = new AnnotatedElementKey(this.method, this.targetClass);
 		Method targetMethod = this.methodCache.get(methodKey);
 		if (targetMethod == null) {
 			targetMethod = AopUtils.getMostSpecificMethod(this.method, this.targetClass);

spring-context/src/main/java/org/springframework/cache/interceptor/ExpressionEvaluator.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -22,27 +22,27 @@
 import java.util.concurrent.ConcurrentHashMap;
 
 import org.springframework.cache.Cache;
+import org.springframework.context.expression.AnnotatedElementKey;
+import org.springframework.context.expression.CachedExpressionEvaluator;
 import org.springframework.core.DefaultParameterNameDiscoverer;
 import org.springframework.core.ParameterNameDiscoverer;
 import org.springframework.expression.EvaluationContext;
 import org.springframework.expression.Expression;
-import org.springframework.expression.spel.standard.SpelExpressionParser;
-import org.springframework.util.ObjectUtils;
 
 /**
  * Utility class handling the SpEL expression parsing.
  * Meant to be used as a reusable, thread-safe component.
  *
  * <p>Performs internal caching for performance reasons
- * using {@link MethodCacheKey}.
+ * using {@link AnnotatedElementKey}.
  *
  * @author Costin Leau
  * @author Phillip Webb
  * @author Sam Brannen
  * @author Stephane Nicoll
  * @since 3.1
  */
-class ExpressionEvaluator {
+class ExpressionEvaluator extends CachedExpressionEvaluator {
 
 	/**
 	 * Indicate that there is no result variable.
@@ -59,9 +59,6 @@ class ExpressionEvaluator {
 	 */
 	public static final String RESULT_VARIABLE = "result";
 
-
-	private final SpelExpressionParser parser = new SpelExpressionParser();
-
 	// shared param discoverer since it caches data internally
 	private final ParameterNameDiscoverer paramNameDiscoverer = new DefaultParameterNameDiscoverer();
 
@@ -71,7 +68,8 @@ class ExpressionEvaluator {
 
 	private final Map<ExpressionKey, Expression> unlessCache = new ConcurrentHashMap<ExpressionKey, Expression>(64);
 
-	private final Map<MethodCacheKey, Method> targetMethodCache = new ConcurrentHashMap<MethodCacheKey, Method>(64);
+	private final Map<AnnotatedElementKey, Method> targetMethodCache =
+			new ConcurrentHashMap<AnnotatedElementKey, Method>(64);
 
 
 	/**
@@ -111,61 +109,17 @@ else if (result != NO_RESULT) {
 		return evaluationContext;
 	}
 
-	public Object key(String keyExpression, MethodCacheKey methodKey, EvaluationContext evalContext) {
-		return getExpression(this.keyCache, keyExpression, methodKey).getValue(evalContext);
+	public Object key(String keyExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
+		return getExpression(this.keyCache, methodKey, keyExpression).getValue(evalContext);
 	}
 
-	public boolean condition(String conditionExpression, MethodCacheKey methodKey, EvaluationContext evalContext) {
-		return getExpression(this.conditionCache, conditionExpression, methodKey).getValue(evalContext, boolean.class);
+	public boolean condition(String conditionExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
+		return getExpression(this.conditionCache, methodKey, conditionExpression).getValue(evalContext, boolean.class);
 	}
 
-	public boolean unless(String unlessExpression, MethodCacheKey methodKey, EvaluationContext evalContext) {
-		return getExpression(this.unlessCache, unlessExpression, methodKey).getValue(evalContext, boolean.class);
-	}
-
-	private Expression getExpression(Map<ExpressionKey, Expression> cache, String expression, MethodCacheKey methodKey) {
-		ExpressionKey key = createKey(methodKey, expression);
-		Expression expr = cache.get(key);
-		if (expr == null) {
-			expr = this.parser.parseExpression(expression);
-			cache.put(key, expr);
-		}
-		return expr;
+	public boolean unless(String unlessExpression, AnnotatedElementKey methodKey, EvaluationContext evalContext) {
+		return getExpression(this.unlessCache, methodKey, unlessExpression).getValue(evalContext, boolean.class);
 	}
 
-	private ExpressionKey createKey(MethodCacheKey methodCacheKey, String expression) {
-		return new ExpressionKey(methodCacheKey, expression);
-	}
-
-
-	private static class ExpressionKey {
-
-		private final MethodCacheKey methodCacheKey;
-
-		private final String expression;
-
-		public ExpressionKey(MethodCacheKey methodCacheKey, String expression) {
-			this.methodCacheKey = methodCacheKey;
-			this.expression = expression;
-		}
-
-		@Override
-		public boolean equals(Object other) {
-			if (this == other) {
-				return true;
-			}
-			if (!(other instanceof ExpressionKey)) {
-				return false;
-			}
-			ExpressionKey otherKey = (ExpressionKey) other;
-			return (this.methodCacheKey.equals(otherKey.methodCacheKey) &&
-					ObjectUtils.nullSafeEquals(this.expression, otherKey.expression));
-		}
-
-		@Override
-		public int hashCode() {
-			return this.methodCacheKey.hashCode() * 29 + (this.expression != null ? this.expression.hashCode() : 0);
-		}
-	}
 
 }

spring-context/src/main/java/org/springframework/cache/interceptor/MethodCacheKey.java renamed to spring-context/src/main/java/org/springframework/context/expression/AnnotatedElementKey.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -14,32 +14,35 @@
  * limitations under the License.
  */
 
-package org.springframework.cache.interceptor;
+package org.springframework.context.expression;
 
-import java.lang.reflect.Method;
+import java.lang.reflect.AnnotatedElement;
 
 import org.springframework.util.Assert;
 import org.springframework.util.ObjectUtils;
 
 /**
- * Represent a method on a particular {@link Class} and  is suitable as a key.
- *
- * <p>Mainly for internal use within the framework.
+ * Represent an {@link AnnotatedElement} on a particular {@link Class}
+ * and is suitable as a key.
  *
  * @author Costin Leau
  * @author Stephane Nicoll
- * @since 4.0.4
+ * @since 4.2.0
+ * @see CachedExpressionEvaluator
  */
-public final class MethodCacheKey {
+public final class AnnotatedElementKey {
 
-	private final Method method;
+	private final AnnotatedElement element;
 
 	private final Class<?> targetClass;
 
-
-	public MethodCacheKey(Method method, Class<?> targetClass) {
-		Assert.notNull(method, "method must be set.");
-		this.method = method;
+	/**
+	 * Create a new instance with the specified {@link AnnotatedElement} and
+	 * optional target {@link Class}.
+	 */
+	public AnnotatedElementKey(AnnotatedElement element, Class<?> targetClass) {
+		Assert.notNull(element, "AnnotatedElement must be set.");
+		this.element = element;
 		this.targetClass = targetClass;
 	}
 
@@ -49,18 +52,17 @@ public boolean equals(Object other) {
 		if (this == other) {
 			return true;
 		}
-		if (!(other instanceof MethodCacheKey)) {
+		if (!(other instanceof AnnotatedElementKey)) {
 			return false;
 		}
-		MethodCacheKey otherKey = (MethodCacheKey) other;
-		return (this.method.equals(otherKey.method) &&
+		AnnotatedElementKey otherKey = (AnnotatedElementKey) other;
+		return (this.element.equals(otherKey.element) &&
 				ObjectUtils.nullSafeEquals(this.targetClass, otherKey.targetClass));
 	}
 
-
 	@Override
 	public int hashCode() {
-		return this.method.hashCode() + (this.targetClass != null ? this.targetClass.hashCode() * 29 : 0);
+		return this.element.hashCode() + (this.targetClass != null ? this.targetClass.hashCode() * 29 : 0);
 	}
 
 }