aspectjexpressionpointcut.java

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/*
 * Copyright 2002-2007 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.aop.aspectj;

import java.lang.reflect.Method;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

import org.aopalliance.intercept.MethodInvocation;
import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.aspectj.weaver.BCException;
import org.aspectj.weaver.reflect.ReflectionWorld;
import org.aspectj.weaver.tools.JoinPointMatch;
import org.aspectj.weaver.tools.PointcutExpression;
import org.aspectj.weaver.tools.PointcutParameter;
import org.aspectj.weaver.tools.PointcutParser;
import org.aspectj.weaver.tools.PointcutPrimitive;
import org.aspectj.weaver.tools.ShadowMatch;

import org.springframework.aop.ClassFilter;
import org.springframework.aop.IntroductionAwareMethodMatcher;
import org.springframework.aop.MethodMatcher;
import org.springframework.aop.ProxyMethodInvocation;
import org.springframework.aop.interceptor.ExposeInvocationInterceptor;
import org.springframework.aop.support.AbstractExpressionPointcut;
import org.springframework.aop.support.AopUtils;
import org.springframework.util.ObjectUtils;
import org.springframework.util.StringUtils;

/**
 * Spring {@link org.springframework.aop.Pointcut} implementation
 * that uses the AspectJ weaver to evaluate a pointcut expression.
 *
 * <p>The pointcut expression value is an AspectJ expression. This can
 * reference other pointcuts and use composition and other operations.
 *
 * <p>Naturally, as this is to be processed by Spring AOP's proxy-based model,
 * only method execution pointcuts are supported.
 *
 * @author Rob Harrop
 * @author Adrian Colyer
 * @author Rod Johnson
 * @author Juergen Hoeller
 * @author Ramnivas Laddad
 * @since 2.0
 */
public class AspectJExpressionPointcut extends AbstractExpressionPointcut
		implements ClassFilter, IntroductionAwareMethodMatcher {

	private static final Set DEFAULT_SUPPORTED_PRIMITIVES = new HashSet();

	static {
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.EXECUTION);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.ARGS);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.REFERENCE);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.THIS);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.TARGET);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.WITHIN);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.AT_ANNOTATION);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.AT_WITHIN);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.AT_ARGS);
		DEFAULT_SUPPORTED_PRIMITIVES.add(PointcutPrimitive.AT_TARGET);
	}


	private static final Log logger = LogFactory.getLog(AspectJExpressionPointcut.class);

	private final Map shadowMapCache = new HashMap();

	private PointcutParser pointcutParser;

	private Class pointcutDeclarationScope;

	private String[] pointcutParameterNames = new String[0];

	private Class[] pointcutParameterTypes = new Class[0];

	private PointcutExpression pointcutExpression;


	/**
	 * Create a new default AspectJExpressionPointcut.
	 */
	public AspectJExpressionPointcut() {
		this(DEFAULT_SUPPORTED_PRIMITIVES);
	}

	/**
	 * Create a new AspectJExpressionPointcut with the given supported primitives.
	 * @param supportedPrimitives Set of {@link org.aspectj.weaver.tools.PointcutPrimitive}
	 * instances
	 */
	public AspectJExpressionPointcut(Set supportedPrimitives) {
		this.pointcutParser =
				PointcutParser.getPointcutParserSupportingSpecifiedPrimitivesAndUsingContextClassloaderForResolution(
						supportedPrimitives);
	}

	/**
	 * Create a new AspectJExpressionPointcut with the given settings.
	 * @param declarationScope the declaration scope for the pointcut
	 * @param paramNames the parameter names for the pointcut
	 * @param paramTypes the parameter types for the pointcut
	 */
	public AspectJExpressionPointcut(Class declarationScope, String[] paramNames, Class[] paramTypes) {
		this(DEFAULT_SUPPORTED_PRIMITIVES);
		this.pointcutDeclarationScope = declarationScope;
		if (paramNames.length != paramTypes.length) {
			throw new IllegalStateException(
					"Number of pointcut parameter names must match number of pointcut parameter types");
		}
		this.pointcutParameterNames = paramNames;
		this.pointcutParameterTypes = paramTypes;
	}


	/**
	 * Set the declaration scope for the pointcut.
	 */
	public void setPointcutDeclarationScope(Class pointcutDeclarationScope) {
		this.pointcutDeclarationScope = pointcutDeclarationScope;
	}

	/**
	 * Set the parameter names for the pointcut.
	 */
	public void setParameterNames(String[] names) {
		this.pointcutParameterNames = names;
	}

	/**
	 * Set the parameter types for the pointcut.
	 */
	public void setParameterTypes(Class[] types) {
		this.pointcutParameterTypes = types;
	}


	public ClassFilter getClassFilter() {
		checkReadyToMatch();
		return this;
	}

	public MethodMatcher getMethodMatcher() {
		checkReadyToMatch();
		return this;
	}


	/**
	 * Check whether this pointcut is ready to match,
	 * lazily building the underlying AspectJ pointcut expression.
	 */
	private void checkReadyToMatch() {
		if (getExpression() == null) {
			throw new IllegalStateException("Must set property 'expression' before attempting to match");
		}
		if (this.pointcutExpression == null) {
			this.pointcutExpression = buildPointcutExpression();
		}
	}

	/**
	 * Build the underlying AspectJ pointcut expression.
	 */
	private PointcutExpression buildPointcutExpression() {
		PointcutParameter[] pointcutParameters = new PointcutParameter[this.pointcutParameterNames.length];
		for (int i = 0; i < pointcutParameters.length; i++) {
			pointcutParameters[i] = this.pointcutParser.createPointcutParameter(
					this.pointcutParameterNames[i], this.pointcutParameterTypes[i]);
		}
		return this.pointcutParser.parsePointcutExpression(
				replaceBooleanOperators(getExpression()), this.pointcutDeclarationScope, pointcutParameters);
	}

	/**
	 * If a pointcut expression has been specified in XML, the user cannot
	 * write <code>and</code> as "&&" (though &amp;&amp; will work).
	 * We also allow <code>and</code> between two pointcut sub-expressions.
	 * <p>This method converts back to <code>&&</code> for the AspectJ pointcut parser.
	 */
	private String replaceBooleanOperators(String pcExpr) {
		pcExpr = StringUtils.replace(pcExpr," and "," && ");
		pcExpr = StringUtils.replace(pcExpr, " or ", " || ");
		pcExpr = StringUtils.replace(pcExpr, " not ", " ! ");
		return pcExpr;
	}

	/**
	 * Return the underlying AspectJ pointcut expression.
	 */
	public PointcutExpression getPointcutExpression() {
		checkReadyToMatch();
		return this.pointcutExpression;
	}


	public boolean matches(Class targetClass) {
		checkReadyToMatch();
		try {
			return this.pointcutExpression.couldMatchJoinPointsInType(targetClass);
		}
		catch (BCException ex) {
			logger.debug("PointcutExpression matching rejected target class", ex);
			return false;
		}
	}

	public boolean matches(Method method, Class targetClass, boolean beanHasIntroductions) {
		checkReadyToMatch();
		Method targetMethod = AopUtils.getMostSpecificMethod(method, targetClass);
		ShadowMatch shadowMatch = null;
		try {
			shadowMatch = getShadowMatch(targetMethod, method);
		}
		catch (ReflectionWorld.ReflectionWorldException ex) {
			// Could neither introspect the target class nor the proxy class ->
			// let's simply consider this method as non-matching.
			return false;
		}

		// Special handling for this, target, @this, @target, @annotation
		// in Spring - we can optimize since we know we have exactly this class,
		// and there will never be matching subclass at runtime.
		if (shadowMatch.alwaysMatches()) {
			return true;
		}
		else if (shadowMatch.neverMatches()) {
			return false;
		}
		else {
		  // the maybe case
		  return (beanHasIntroductions || matchesIgnoringSubtypes(shadowMatch));
		}
	}

	public boolean matches(Method method, Class targetClass) {
		return matches(method, targetClass, false);
	}

	public boolean isRuntime() {
		checkReadyToMatch();
		return this.pointcutExpression.mayNeedDynamicTest();
	}

	public boolean matches(Method method, Class targetClass, Object[] args) {
		checkReadyToMatch();
		ShadowMatch shadowMatch = null;
		ShadowMatch originalShadowMatch = null;
		try {
			shadowMatch = getShadowMatch(AopUtils.getMostSpecificMethod(method, targetClass), method);
			originalShadowMatch = getShadowMatch(method, method);
		}
		catch (ReflectionWorld.ReflectionWorldException ex) {
			// Could neither introspect the target class nor the proxy class ->
			// let's simply consider this method as non-matching.
			return false;
		}

		// Bind Spring AOP proxy to AspectJ "this" and Spring AOP target to AspectJ target,
		// consistent with return of MethodInvocationProceedingJoinPoint
		ProxyMethodInvocation pmi = null;
		Object targetObject = null;
		Object thisObject = null;
		try {
			MethodInvocation mi = ExposeInvocationInterceptor.currentInvocation();
			targetObject = mi.getThis();
			if (!(mi instanceof ProxyMethodInvocation)) {
				throw new IllegalStateException("MethodInvocation is not a Spring ProxyMethodInvocation: " + mi);
			}
			pmi = (ProxyMethodInvocation) mi;
			thisObject = pmi.getProxy();
		}
		catch (IllegalStateException ex) {
			// No current invocation...
			// TODO: Should we really proceed here?
			logger.debug("Couldn't access current invocation - matching with limited context: " + ex);
		}

		JoinPointMatch joinPointMatch = shadowMatch.matchesJoinPoint(thisObject, targetObject, args);
		
		/*
		 * Do a final check to see if any this(TYPE) kind of residue match. For
		 * this purpose, we use the original method's (proxy method's) shadow to
		 * ensure that 'this' is correctly checked against. Without this check,
		 * we get incorrect match on this(TYPE) where TYPE matches the target
		 * type but not 'this' (as would be the case of JDK dynamic proxies).
		 * 
		 * See SPR-2979 for the original bug.
		 */
		RuntimeTestWalker originalMethodResidueTest = new RuntimeTestWalker(originalShadowMatch);
		if(!originalMethodResidueTest.testThisInstanceOfResidue(thisObject)) {
			return false;
		}

		if (joinPointMatch.matches() && pmi != null) {
			bindParameters(pmi, joinPointMatch);
		}
		return joinPointMatch.matches();
	}


	/**
	 * A match test returned maybe - if there are any subtype sensitive variables
	 * involved in the test (this, target, at_this, at_target, at_annotation) then
	 * we say this is not a match as in Spring there will never be a different
	 * runtime subtype.
	 */
	private boolean matchesIgnoringSubtypes(ShadowMatch shadowMatch) {
		return !(new RuntimeTestWalker(shadowMatch).testsSubtypeSensitiveVars());
	}

	private void bindParameters(ProxyMethodInvocation invocation, JoinPointMatch jpm) {
		// Note: Can't use JoinPointMatch.getClass().getName() as the key, since
		// Spring AOP does all the matching at a join point, and then all the invocations
		// under this scenario, if we just use JoinPointMatch as the key, then
		// 'last man wins' which is not what we want at all.
		// Using the expression is guaranteed to be safe, since 2 identical expressions
		// are guaranteed to bind in exactly the same way.
		invocation.setUserAttribute(getExpression(), jpm);
	}

	private ShadowMatch getShadowMatch(Method targetMethod, Method originalMethod) {
		synchronized (this.shadowMapCache) {
			ShadowMatch shadowMatch = (ShadowMatch) this.shadowMapCache.get(targetMethod);
			if (shadowMatch == null) {
				try {
					shadowMatch = this.pointcutExpression.matchesMethodExecution(targetMethod);
				}
				catch (ReflectionWorld.ReflectionWorldException ex) {
					// Failed to introspect target method, probably because it has been loaded
					// in a special ClassLoader. Let's try the original method instead...
					if (targetMethod == originalMethod) {
						throw ex;
					}
					shadowMatch = this.pointcutExpression.matchesMethodExecution(originalMethod);
				}
				this.shadowMapCache.put(targetMethod, shadowMatch);
			}
			return shadowMatch;
		}
	}


	public boolean equals(Object other) {
		if (this == other) {
			return true;
		}
		if (!(other instanceof AspectJExpressionPointcut)) {
			return false;
		}
		AspectJExpressionPointcut otherPc = (AspectJExpressionPointcut) other;
		return ObjectUtils.nullSafeEquals(this.getExpression(), otherPc.getExpression()) &&
				ObjectUtils.nullSafeEquals(this.pointcutDeclarationScope, otherPc.pointcutDeclarationScope) &&
				ObjectUtils.nullSafeEquals(this.pointcutParameterNames, otherPc.pointcutParameterNames) &&
				ObjectUtils.nullSafeEquals(this.pointcutParameterTypes, otherPc.pointcutParameterTypes);
	}

	public int hashCode() {
		int hashCode = ObjectUtils.nullSafeHashCode(this.getExpression());
		hashCode = 31 * hashCode + ObjectUtils.nullSafeHashCode(this.pointcutDeclarationScope);
		hashCode = 31 * hashCode + ObjectUtils.nullSafeHashCode(this.pointcutParameterNames);
		hashCode = 31 * hashCode + ObjectUtils.nullSafeHashCode(this.pointcutParameterTypes);
		return hashCode;
	}

	public String toString() {
		StringBuffer sb = new StringBuffer();
		sb.append("AspectJExpressionPointcut: ");
		if (this.pointcutParameterNames != null && this.pointcutParameterTypes != null) {
			sb.append("(");
			for (int i = 0; i < this.pointcutParameterTypes.length; i++) {
				sb.append(this.pointcutParameterTypes[i].getName());
				sb.append(" ");
				sb.append(this.pointcutParameterNames[i]);
				if ((i+1) < this.pointcutParameterTypes.length) {
					sb.append(", ");
				}
			}
			sb.append(")");
		}
		sb.append(" ");
		if (getExpression() != null) {
			sb.append(getExpression());
		}
		else {
			sb.append("<pointcut expression not set>");
		}
		return sb.toString();
	}

}