/*

 * CDDL HEADER START

 *

 * The contents of this file are subject to the terms of the

 * Common Development and Distribution License (the "License").

 * You may not use this file except in compliance with the License.

 *

 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE

 * or http://www.opensolaris.org/os/licensing.

 * See the License for the specific language governing permissions

 * and limitations under the License.

 *

 * When distributing Covered Code, include this CDDL HEADER in each

 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.

 * If applicable, add the following below this CDDL HEADER, with the

 * fields enclosed by brackets "[]" replaced with your own identifying

 * information: Portions Copyright [yyyy] [name of copyright owner]

 *

 * CDDL HEADER END

 */

/*

 * Copyright (c) 2009, 2012, Oracle and/or its affiliates. All rights reserved.

 */

package com.oracle.solaris.vp.util.misc.finder;

import java.security.*;

public class ItemFinder implements FindingClass {

    //

    // Inner classes

    //

    // A number of classes in the JDK return the current thread's class stack

    // as a Class array, but none exposes this functionality publicly.  The

    // closest is SecurityManager, whose getClassContext method has protected

    // access.  Thus this hack.

    //

    // Note that java.lang.StackTraceElement is insufficient as it does not

    // return the actual Class objects in the stack, which are necessary to

    // retrieve each class's ClassLoader.

    //

    // An alternate approach would be to implement getClassContext() as a native

    // method.

    private static class MySecurityManager extends SecurityManager {

	@Override

	public Class[] getClassContext() {

	    return super.getClassContext();

	}

    }

    //

    // Static data

    //

    private static final MySecurityManager sManager = new MySecurityManager();

    private static final String className = ItemFinder.class.getName();

    //

    // Static methods

    //

    public static Class[] getClassContext() {

	return sManager.getClassContext();

    }

    /**

     * Gets the first class under the last {@link FindingClass} in the class

     * stack.

     */

    public static Class getCallerClass() {

	return AccessController.doPrivileged(

	    new PrivilegedAction<Class>() {

		@Override

		public Class run() {

		    return getCallerClassImp();

		}

	    });

    }

    //

    // Private static methods

    //

    private static Class getCallerClassImp() {

	Class[] stack = getClassContext();

	for (int i = stack.length - 2; i >= 0; i--) {

	    if (FindingClass.class.isAssignableFrom(stack[i])) {

		return stack[i + 1];

	    }

	}

	return null;

    }

}