aspectjadviceparameternamediscoverer.java

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				if (this.parameterNameBindings[i] == null) {
					bindParameterName(i, this.returningName);
					break;
				}
			}
		}
	}


	/**
	 * Parse the string pointcut expression looking for:
	 * @this, @target, @args, @within, @withincode, @annotation.
	 * If we find one of these pointcut expressions, try and extract a candidate variable
	 * name (or variable names, in the case of args).
	 * <p>Some more support from AspectJ in doing this exercise would be nice... :)
	 */
	private void maybeBindAnnotationsFromPointcutExpression() {
		List varNames = new ArrayList();
		String[] tokens = StringUtils.tokenizeToStringArray(this.pointcutExpression, " ");
		for (int i = 0; i < tokens.length; i++) {
			String toMatch = tokens[i];
			int firstParenIndex = toMatch.indexOf("(");
			if (firstParenIndex != -1) {
				toMatch = toMatch.substring(0, firstParenIndex);
			}
			if (singleValuedAnnotationPcds.contains(toMatch)) {
				PointcutBody body = getPointcutBody(tokens, i);
				i += body.numTokensConsumed;
				String varName = maybeExtractVariableName(body.text);
				if (varName != null) {
					varNames.add(varName);
				}
			}
			else if (tokens[i].startsWith("@args(") || tokens[i].equals("@args")) {
				PointcutBody body = getPointcutBody(tokens, i);
				i += body.numTokensConsumed;
				maybeExtractVariableNamesFromArgs(body.text, varNames);
			}
		}

		bindAnnotationsFromVarNames(varNames);
	}

	/**
	 * Match the given list of extracted variable names to argument slots.
	 */
	private void bindAnnotationsFromVarNames(List varNames) {
		if (!varNames.isEmpty()) {
			// we have work to do...
			int numAnnotationSlots = countNumberOfUnboundAnnotationArguments();
			if (numAnnotationSlots > 1) {
				throw new AmbiguousBindingException("Found " + varNames.size() +
						" potential annotation variable(s), and " +
						numAnnotationSlots + " potential argument slots");
			}
			else if (numAnnotationSlots == 1) {
				if (varNames.size() == 1) {
					// it's a match
					findAndBind(annotationClass, (String) varNames.get(0));
				}
				else {
					// multiple candidate vars, but only one slot
					throw new IllegalArgumentException("Found " + varNames.size() +
							" candidate annotation binding variables" +
							" but only one potential argument binding slot");
				}
			}
			else {
				// no slots so presume those candidate vars were actually type names
			}
		}
	}

	/*
	 * If the token starts meets Java identifier conventions, it's in.
	 */
	private String maybeExtractVariableName(String candidateToken) {
		if (candidateToken == null || candidateToken.equals("")) {
			return null;
		}
		if (Character.isJavaIdentifierStart(candidateToken.charAt(0)) &&
				Character.isLowerCase(candidateToken.charAt(0))) {
			char[] tokenChars = candidateToken.toCharArray();
			for (int i = 0; i < tokenChars.length; i++) {
				if (!Character.isJavaIdentifierPart(tokenChars[i])) {
					return null;
				}
			}
			return candidateToken;
		}
		else {
			return null;
		}
	}

	/**
	 * Given an args pointcut body (could be <code>args</code> or <code>at_args</code>),
	 * add any candidate variable names to the given list.
	 */
	private void maybeExtractVariableNamesFromArgs(String argsSpec, List varNames) {
		if (argsSpec == null) {
			return;
		}

		String[] tokens = StringUtils.tokenizeToStringArray(argsSpec, ",");
		for (int i = 0; i < tokens.length; i++) {
			tokens[i] = StringUtils.trimWhitespace(tokens[i]);
			String varName = maybeExtractVariableName(tokens[i]);
			if (varName != null) {
				varNames.add(varName);
			}
		}
	}

	/**
	 * Parse the string pointcut expression looking for this(), target() and args() expressions.
	 * If we find one, try and extract a candidate variable name and bind it.
	 */
	private void maybeBindThisOrTargetOrArgsFromPointcutExpression() {
		if (this.numberOfRemainingUnboundArguments > 1) {
			throw new AmbiguousBindingException("Still " + this.numberOfRemainingUnboundArguments
					+ " unbound args at this(),target(),args() binding stage, with no way to determine between them");
		}

		List varNames = new ArrayList();
		String[] tokens = StringUtils.tokenizeToStringArray(this.pointcutExpression, " ");
		for (int i = 0; i < tokens.length; i++) {
			if (tokens[i].equals("this") ||
					tokens[i].startsWith("this(") ||
					tokens[i].equals("target") ||
					tokens[i].startsWith("target(")) {
				PointcutBody body = getPointcutBody(tokens, i);
				i += body.numTokensConsumed;
				String varName = maybeExtractVariableName(body.text);
				if (varName != null) {
					varNames.add(varName);
				}
			}
			else if (tokens[i].equals("args") || tokens[i].startsWith("args(")) {
				PointcutBody body = getPointcutBody(tokens, i);
				i += body.numTokensConsumed;
				List candidateVarNames = new ArrayList();
				maybeExtractVariableNamesFromArgs(body.text, candidateVarNames);
				// we may have found some var names that were bound in previous primitive args binding step,
				// filter them out...
				for (Iterator iter = candidateVarNames.iterator(); iter.hasNext();) {
					String varName = (String) iter.next();
					if (!alreadyBound(varName)) {
						varNames.add(varName);
					}
				}
			}
		}


		if (varNames.size() > 1) {
			throw new AmbiguousBindingException("Found " + varNames.size() +
					" candidate this(), target() or args() variables but only one unbound argument slot");
		}
		else if (varNames.size() == 1) {
			for (int j = 0; j < this.parameterNameBindings.length; j++) {
				if (isUnbound(j)) {
					bindParameterName(j, (String) varNames.get(0));
					break;
				}
			}
		}
		// else varNames.size must be 0 and we have nothing to bind.
	}

	private void maybeBindReferencePointcutParameter() {
		if (this.numberOfRemainingUnboundArguments > 1) {
			throw new AmbiguousBindingException("Still " + this.numberOfRemainingUnboundArguments
					+ " unbound args at reference pointcut binding stage, with no way to determine between them");
		}

		List varNames = new ArrayList();
		String[] tokens = StringUtils.tokenizeToStringArray(this.pointcutExpression, " ");
		for (int i = 0; i < tokens.length; i++) {
			String toMatch = tokens[i];
			if (toMatch.startsWith("!")) {
				toMatch = toMatch.substring(1);
			}
			int firstParenIndex = toMatch.indexOf("(");
			if (firstParenIndex != -1) {
				toMatch = toMatch.substring(0, firstParenIndex);
			}
			else {
				if (tokens.length < i + 2) {
					// no "(" and nothing following
					continue;
				}
				else {
					String nextToken = tokens[i + 1];
					if (nextToken.charAt(0) != '(') {
						// next token is not "(" either, can't be a pc...
						continue;
					}
				}

			}

			// eat the body
			PointcutBody body = getPointcutBody(tokens, i);
			i += body.numTokensConsumed;

			if (!nonReferencePointcutTokens.contains(toMatch)) {
				// then it could be a reference pointcut
				String varName = maybeExtractVariableName(body.text);
				if (varName != null) {
					varNames.add(varName);
				}
			}
		}

		if (varNames.size() > 1) {
			throw new AmbiguousBindingException("Found " + varNames.size() +
					" candidate reference pointcut variables but only one unbound argument slot");
		}
		else if (varNames.size() == 1) {
			for (int j = 0; j < this.parameterNameBindings.length; j++) {
				if (isUnbound(j)) {
					bindParameterName(j, (String) varNames.get(0));
					break;
				}
			}
		}
		// else varNames.size must be 0 and we have nothing to bind.
	}

	/*
	 * We've found the start of a binding pointcut at the given index into the
	 * token array. Now we need to extract the pointcut body and return it.
	 */
	private PointcutBody getPointcutBody(String[] tokens, int startIndex) {
		int numTokensConsumed = 0;
		String currentToken = tokens[startIndex];
		int bodyStart = currentToken.indexOf('(');
		if (currentToken.charAt(currentToken.length() - 1) == ')') {
			// It's an all in one... get the text between the first (and the last)
			return new PointcutBody(0, currentToken.substring(bodyStart + 1, currentToken.length() - 1));
		}
		else {
			StringBuffer sb = new StringBuffer();
			if (bodyStart >= 0 && bodyStart != (currentToken.length() - 1)) {
				sb.append(currentToken.substring(bodyStart + 1));
				sb.append(" ");
			}
			numTokensConsumed++;
			int currentIndex = startIndex + numTokensConsumed;
			while (currentIndex < tokens.length) {
				if (tokens[currentIndex].equals("(")) {
					currentIndex++;
					continue;
				}

				if (tokens[currentIndex].endsWith(")")) {
					sb.append(tokens[currentIndex].substring(0, tokens[currentIndex].length() - 1));
					return new PointcutBody(numTokensConsumed, sb.toString().trim());
				}

				String toAppend = tokens[currentIndex];
				if (toAppend.startsWith("(")) {
					toAppend = toAppend.substring(1);
				}
				sb.append(toAppend);
				sb.append(" ");
				currentIndex++;
				numTokensConsumed++;
			}

		}

		// We looked and failed...
		return new PointcutBody(numTokensConsumed, null);
	}

	/**
	 * Match up args against unbound arguments of primitive types
	 */
	private void maybeBindPrimitiveArgsFromPointcutExpression() {
		int numUnboundPrimitives = countNumberOfUnboundPrimitiveArguments();
		if (numUnboundPrimitives > 1) {
			throw new AmbiguousBindingException("Found '" + numUnboundPrimitives +
					"' unbound primitive arguments with no way to distinguish between them.");
		}
		if (numUnboundPrimitives == 1) {
			// Look for arg variable and bind it if we find exactly one...
			List varNames = new ArrayList();
			String[] tokens = StringUtils.tokenizeToStringArray(this.pointcutExpression, " ");
			for (int i = 0; i < tokens.length; i++) {
				if (tokens[i].equals("args") || tokens[i].startsWith("args(")) {
					PointcutBody body = getPointcutBody(tokens, i);
					i += body.numTokensConsumed;
					maybeExtractVariableNamesFromArgs(body.text, varNames);
				}
			}
			if (varNames.size() > 1) {
				throw new AmbiguousBindingException("Found " + varNames.size() +
						" candidate variable names but only one candidate binding slot when matching primitive args");
			}
			else if (varNames.size() == 1) {
				// 1 primitive arg, and one candidate...
				for (int i = 0; i < this.argumentTypes.length; i++) {
					if (isUnbound(i) && this.argumentTypes[i].isPrimitive()) {
						bindParameterName(i, (String) varNames.get(0));
						break;
					}
				}
			}
		}
	}

	/*
	 * Return true if the parameter name binding for the given parameter
	 * index has not yet been assigned.
	 */
	private boolean isUnbound(int i) {
		return this.parameterNameBindings[i] == null;
	}

	private boolean alreadyBound(String varName) {
		for (int i = 0; i < this.parameterNameBindings.length; i++) {
			if (!isUnbound(i) && varName.equals(this.parameterNameBindings[i])) {
				return true;
			}
		}
		return false;
	}

	/*
	 * Return <code>true</code> if the given argument type is a subclass
	 * of the given supertype.
	 */
	private boolean isSubtypeOf(Class supertype, int argumentNumber) {
		return supertype.isAssignableFrom(this.argumentTypes[argumentNumber]);
	}

	private int countNumberOfUnboundAnnotationArguments() {
		if (annotationClass == null) {
			// We're running on a JDK < 1.5
			return 0;
		}

		int count = 0;
		for (int i = 0; i < this.argumentTypes.length; i++) {
			if (isUnbound(i) && isSubtypeOf(annotationClass, i)) {
				count++;
			}
		}
		return count;
	}

	private int countNumberOfUnboundPrimitiveArguments() {
		int count = 0;
		for (int i = 0; i < this.argumentTypes.length; i++) {
			if (isUnbound(i) && this.argumentTypes[i].isPrimitive()) {
				count++;
			}
		}
		return count;
	}

	/*
	 * Find the argument index with the given type, and bind the given
	 * <code>varName</code> in that position.
	 */
	private void findAndBind(Class argumentType, String varName) {
		for (int i = 0; i < this.argumentTypes.length; i++) {
			if (isUnbound(i) && isSubtypeOf(argumentType, i)) {
				bindParameterName(i, varName);
				return;
			}
		}
		throw new IllegalStateException("Expected to find an unbound argument of type '" +
				argumentType.getName() + "'");
	}


	/**
	 * Simple struct to hold the extracted text from a pointcut body, together
	 * with the number of tokens consumed in extracting it.
	 */
	private static class PointcutBody {

		private int numTokensConsumed;

		private String text;

		public PointcutBody(int tokens, String text) {
			this.numTokensConsumed = tokens;
			this.text = text;
		}
	}


	/**
	 * Thrown in response to an ambiguous binding being detected when
	 * trying to resolve a method's parameter names.
	 */
	public static class AmbiguousBindingException extends RuntimeException {

		/**
		 * Construct a new AmbiguousBindingException with the specified message.
		 * @param msg the detail message
		 */
		public AmbiguousBindingException(String msg) {
			super(msg);
		}
	}

}