Revision of SpelCompiler support, resolving a subpackage cycle through moving CodeFlow and CompilablePropertyAccessor to the main spel package

Also contains explicit ClassLoader management, passed through StandardBeanExpressionResolver and SpelParserConfiguration to SpelCompiler lookup.

Issue: SPR-10943

spring-context/src/main/java/org/springframework/context/expression/StandardBeanExpressionResolver.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * Copyright 2002-2014 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.
@@ -27,6 +27,7 @@ import org.springframework.core.convert.ConversionService;
 import org.springframework.expression.Expression;
 import org.springframework.expression.ExpressionParser;
 import org.springframework.expression.ParserContext;
+import org.springframework.expression.spel.SpelParserConfiguration;
 import org.springframework.expression.spel.standard.SpelExpressionParser;
 import org.springframework.expression.spel.support.StandardEvaluationContext;
 import org.springframework.expression.spel.support.StandardTypeConverter;
@@ -58,7 +59,7 @@ public class StandardBeanExpressionResolver implements BeanExpressionResolver {
 
 	private String expressionSuffix = DEFAULT_EXPRESSION_SUFFIX;
 
-	private ExpressionParser expressionParser = new SpelExpressionParser();
+	private ExpressionParser expressionParser;
 
 	private final Map<String, Expression> expressionCache = new ConcurrentHashMap<String, Expression>(256);
 
@@ -81,6 +82,23 @@ public class StandardBeanExpressionResolver implements BeanExpressionResolver {
 	};
 
 
+	/**
+	 * Create a new {@code StandardBeanExpressionResolver} with default settings.
+	 */
+	public StandardBeanExpressionResolver() {
+		this.expressionParser = new SpelExpressionParser();
+	}
+
+	/**
+	 * Create a new {@code StandardBeanExpressionResolver} with the given bean class loader,
+	 * using it as the basis for expression compilation.
+	 * @param beanClassLoader the factory's bean class loader
+	 */
+	public StandardBeanExpressionResolver(ClassLoader beanClassLoader) {
+		this.expressionParser = new SpelExpressionParser(new SpelParserConfiguration(null, beanClassLoader));
+	}
+
+
 	/**
 	 * Set the prefix that an expression string starts with.
 	 * The default is "#{".

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -548,7 +548,7 @@ public abstract class AbstractApplicationContext extends DefaultResourceLoader
 	protected void prepareBeanFactory(ConfigurableListableBeanFactory beanFactory) {
 		// Tell the internal bean factory to use the context's class loader etc.
 		beanFactory.setBeanClassLoader(getClassLoader());
-		beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver());
+		beanFactory.setBeanExpressionResolver(new StandardBeanExpressionResolver(beanFactory.getBeanClassLoader()));
 		beanFactory.addPropertyEditorRegistrar(new ResourceEditorRegistrar(this, getEnvironment()));
 
 		// Configure the bean factory with context callbacks.