/*
 * FindBugs - Find Bugs in Java programs
 * Copyright (C) 2003-2007 University of Maryland
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

package edu.umd.cs.findbugs.ba.ch;

import edu.umd.cs.findbugs.annotations.CheckForNull;
import edu.umd.cs.findbugs.ba.XClass;
import edu.umd.cs.findbugs.classfile.ClassDescriptor;

/**
 * Visitor interface for traversals of the inheritance graph.
 * 
 * @see Subtypes2
 * @author David Hovemeyer
 */
public interface InheritanceGraphVisitor {
	/**
	 * Visit a class vertex in the inheritance graph.
	 * 
	 * @param classDescriptor ClassDescriptor of the class vertex
	 * @param xclass          XClass object containing information about the class; null if class cannot be resolved
	 * @return true if traversal should continue, false otherwise
	 */
	public boolean visitClass(ClassDescriptor classDescriptor, @CheckForNull XClass xclass);

	/**
	 * Visit an inheritance edge in the inheritance graph.
	 * 
	 * @param sourceDesc ClassDescriptor of the source class (subtype)
	 * @param source     XClass object containing information about source class
	 * @param targetDesc ClassDescriptor of the target class (supertype)
	 * @param target     XClass object containing information about target class; null if class cannot be resolved
	 * @return true if traversal should continue, false otherwise
	 */
	public boolean visitEdge(
			ClassDescriptor sourceDesc,
			XClass source,
			ClassDescriptor targetDesc,
			@CheckForNull XClass target);
}
