http://www.aspectj.org: The AspectJ weaver introduces advices to java classes
  • Andy Clement 
package org.aspectj.apache.bcel;

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 * are met:
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 *    notice, this list of conditions and the following disclaimer.
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 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
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 * 4. The names "Apache" and "Apache Software Foundation" and
 *    "Apache BCEL" must not be used to endorse or promote products
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 * information on the Apache Software Foundation, please see
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 */

import java.io.IOException;

import org.aspectj.apache.bcel.classfile.JavaClass;
import org.aspectj.apache.bcel.util.ClassPath;
import org.aspectj.apache.bcel.util.SyntheticRepository;


The repository maintains informations about class interdependencies, e.g., whether a class is a sub-class of another. Delegates
actual class loading to SyntheticRepository with current class path by default.

Author:M. Dahm
See Also:
Version:$Id: Repository.java,v 1.6 2009/09/09 22:18:20 aclement Exp $
/**
 * The repository maintains informations about class interdependencies, e.g., whether a class is a sub-class of another. Delegates
 * actual class loading to SyntheticRepository with current class path by default.
 * 
 * @see org.aspectj.apache.bcel.util.Repository
 * @see org.aspectj.apache.bcel.util.SyntheticRepository
 * 
 * @version $Id: Repository.java,v 1.6 2009/09/09 22:18:20 aclement Exp $
 * @author <A HREF="mailto:markus.dahm@berlin.de">M. Dahm</A>
 */
public abstract class Repository {
	private static org.aspectj.apache.bcel.util.Repository _repository = null;

	
Returns:currently used repository instance
/**
	 * @return currently used repository instance
	 */
	public static org.aspectj.apache.bcel.util.Repository getRepository() {
		if (_repository == null) {
			_repository = SyntheticRepository.getInstance();
		}
		return _repository;
	}

	
Set repository instance to be used for class loading

/**
	 * Set repository instance to be used for class loading
	 */
	public static void setRepository(org.aspectj.apache.bcel.util.Repository rep) {
		_repository = rep;
	}

	
Lookup class somewhere found on your CLASSPATH, or whereever the repository instance looks for it.

Returns:class object for given fully qualified class name, or null if the class could not be found or parsed correctly
/**
	 * Lookup class somewhere found on your CLASSPATH, or whereever the repository instance looks for it.
	 * 
	 * @return class object for given fully qualified class name, or null if the class could not be found or parsed correctly
	 */
	public static JavaClass lookupClass(String class_name) {
		try {
			JavaClass clazz = getRepository().findClass(class_name);

			if (clazz != null) {
				return clazz;
			}

			return getRepository().loadClass(class_name);
		} catch (ClassNotFoundException ex) {
			return null;
		}
	}

	// /**
	// * Try to find class source via getResourceAsStream().
	// *
	// * @see Class
	// * @return JavaClass object for given runtime class
	// */
	// public static JavaClass lookupClass(Class clazz) {
	// try {
	// return getRepository().loadClass(clazz);
	// } catch (ClassNotFoundException ex) {
	// return null;
	// }
	// }

	
Returns:class file object for given Java class.
/**
	 * @return class file object for given Java class.
	 */
	public static ClassPath.ClassFile lookupClassFile(String class_name) {
		try {
			return ClassPath.getSystemClassPath().getClassFile(class_name);
		} catch (IOException e) {
			return null;
		}
	}

	
Clear the repository.

/**
	 * Clear the repository.
	 */
	public static void clearCache() {
		getRepository().clear();
	}

	
Add clazz to repository if there isn't an equally named class already in there.

Returns:old entry in repository
/**
	 * Add clazz to repository if there isn't an equally named class already in there.
	 * 
	 * @return old entry in repository
	 */
	public static JavaClass addClass(JavaClass clazz) {
		JavaClass old = getRepository().findClass(clazz.getClassName());
		getRepository().storeClass(clazz);
		return old;
	}

	
Remove class with given (fully qualified) name from repository.

/**
	 * Remove class with given (fully qualified) name from repository.
	 */
	public static void removeClass(String clazz) {
		getRepository().removeClass(getRepository().findClass(clazz));
	}

	// /**
	// * Remove given class from repository.
	// */
	// public static void removeClass(JavaClass clazz) {
	// getRepository().removeClass(clazz);
	// }

	// /**
	// * @return list of super classes of clazz in ascending order, i.e., Object is always the last element
	// */
	// public static JavaClass[] getSuperClasses(JavaClass clazz) {
	// return clazz.getSuperClasses();
	// }
	//
	// /**
	// * @return list of super classes of clazz in ascending order, i.e., Object is always the last element. return "null", if class
	// * cannot be found.
	// */
	// public static JavaClass[] getSuperClasses(String class_name) {
	// JavaClass jc = lookupClass(class_name);
	// return jc == null ? null : getSuperClasses(jc);
	// }
	//
	// /**
	// * @return all interfaces implemented by class and its super classes and the interfaces that those interfaces extend, and so
	// on.
	// * (Some people call this a transitive hull).
	// */
	// public static JavaClass[] getInterfaces(JavaClass clazz) {
	// return clazz.getAllInterfaces();
	// }

	// /**
	// * @return all interfaces implemented by class and its super classes and the interfaces that extend those interfaces, and so
	// on
	// */
	// public static JavaClass[] getInterfaces(String class_name) {
	// return getInterfaces(lookupClass(class_name));
	// }

	
Equivalent to runtime "instanceof" operator.

Returns:true, if clazz is an instance of super_class
/**
	 * Equivalent to runtime "instanceof" operator.
	 * 
	 * @return true, if clazz is an instance of super_class
	 */
	public static boolean instanceOf(JavaClass clazz, JavaClass super_class) {
		return clazz.instanceOf(super_class);
	}

	
Returns:true, if clazz is an instance of super_class
/**
	 * @return true, if clazz is an instance of super_class
	 */
	public static boolean instanceOf(String clazz, String super_class) {
		return instanceOf(lookupClass(clazz), lookupClass(super_class));
	}

	// /**
	// * @return true, if clazz is an instance of super_class
	// */
	// public static boolean instanceOf(JavaClass clazz, String super_class) {
	// return instanceOf(clazz, lookupClass(super_class));
	// }

	// /**
	// * @return true, if clazz is an instance of super_class
	// */
	// public static boolean instanceOf(String clazz, JavaClass super_class) {
	// return instanceOf(lookupClass(clazz), super_class);
	// }

	
Returns:true, if clazz is an implementation of interface inter
/**
	 * @return true, if clazz is an implementation of interface inter
	 */
	public static boolean implementationOf(JavaClass clazz, JavaClass inter) {
		return clazz.implementationOf(inter);
	}

	
Returns:true, if clazz is an implementation of interface inter
/**
	 * @return true, if clazz is an implementation of interface inter
	 */
	public static boolean implementationOf(String clazz, String inter) {
		return implementationOf(lookupClass(clazz), lookupClass(inter));
	}

	//
	// /**
	// * @return true, if clazz is an implementation of interface inter
	// */
	// public static boolean implementationOf(JavaClass clazz, String inter) {
	// return implementationOf(clazz, lookupClass(inter));
	// }

	// /**
	// * @return true, if clazz is an implementation of interface inter
	// */
	// public static boolean implementationOf(String clazz, JavaClass inter) {
	// return implementationOf(lookupClass(clazz), inter);
	// }
}