/*
 * Copyright 2002-2006 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 org.aspectj.weaver.tools.PointcutParser;
import org.aspectj.weaver.tools.TypePatternMatcher;

import org.springframework.aop.ClassFilter;
import org.springframework.util.Assert;
import org.springframework.util.StringUtils;

/**
 * Spring AOP {@link ClassFilter} implementation using AspectJ type matching.
 *
 * @author Rod Johnson
 * @since 2.0
 */
public class TypePatternClassFilter implements ClassFilter {

	private String typePattern;

	private TypePatternMatcher aspectJTypePatternMatcher;


	/**
	 * Creates a new instance of the {@link TypePatternClassFilter} class.
	 * <p>This is the JavaBean constructor; be sure to set the
	 * {@link #setTypePattern(String) typePattern} property, else a
	 * no doubt fatal {@link IllegalStateException} will be thrown
	 * when the {@link #matches(Class)} method is first invoked.
	 */
	public TypePatternClassFilter() {
	}

	/**
	 * Create a fully configured {@link TypePatternClassFilter} using the  
	 * given type pattern.
	 * @param typePattern the type pattern that AspectJ weaver should parse
	 * @throws IllegalArgumentException if the supplied <code>typePattern</code> is <code>null</code>
	 * or is recognized as invalid 
	 */
	public TypePatternClassFilter(String typePattern) {
		setTypePattern(typePattern);
	}


	/**
	 * Set the AspectJ type pattern to match.
	 * <p>Examples include:
	 * <code class="code">
	 * org.springframework.beans.*
	 * </code>
	 * This will match any class or interface in the given package.
	 * <code class="code">
	 * org.springframework.beans.ITestBean+
	 * </code>
	 * This will match the <code>ITestBean</code> interface and any class
	 * that implements it.
	 * <p>These conventions are established by AspectJ, not Spring AOP.
	 * @param typePattern the type pattern that AspectJ weaver should parse
	 * @throws IllegalArgumentException if the supplied <code>typePattern</code> is <code>null</code>
	 * or is recognized as invalid 
	 */
	public void setTypePattern(String typePattern) {
		Assert.notNull(typePattern);
		this.typePattern = typePattern;
		this.aspectJTypePatternMatcher =
				PointcutParser.getPointcutParserSupportingAllPrimitivesAndUsingContextClassloaderForResolution().
				parseTypePattern(replaceBooleanOperators(typePattern));
	}

	public String getTypePattern() {
		return typePattern;
	}

	/**
	 * Should the pointcut apply to the given interface or target class?
	 * @param clazz candidate target class
	 * @return whether the advice should apply to this candidate target class
	 * @throws IllegalStateException if no {@link #setTypePattern(String)} has been set
	 */
	public boolean matches(Class clazz) {
		if (this.aspectJTypePatternMatcher == null) {
			throw new IllegalStateException("No 'typePattern' has been set via ctor/setter.");
		}
		return this.aspectJTypePatternMatcher.matches(clazz);
	}

	/**
	 * If a type pattern 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 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;
	}
}
