/*
 * "@(#)Jaas.java	1.1	05/06/15 SMI"
 *
 * Copyright 2006 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Redistribution and use in source and binary forms, with or 
 * without modification, are permitted provided that the following 
 * conditions are met:
 * 
 * -Redistributions of source code must retain the above copyright  
 * notice, this  list of conditions and the following disclaimer.
 * 
 * -Redistribution in binary form must reproduct the above copyright 
 * notice, this list of conditions and the following disclaimer in 
 * the documentation and/or other materials provided with the 
 * distribution.
 * 
 * Neither the name of Sun Microsystems, Inc. or the names of 
 * contributors may be used to endorse or promote products derived 
 * from this software without specific prior written permission.
 * 
 * This software is provided "AS IS," without a warranty of any 
 * kind. ALL EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND 
 * WARRANTIES, INCLUDING ANY IMPLIED WARRANTY OF MERCHANTABILITY, 
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT, ARE HEREBY 
 * EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE LIABLE FOR ANY 
 * DAMAGES OR LIABILITIES  SUFFERED BY LICENSEE AS A RESULT OF  OR 
 * RELATING TO USE, MODIFICATION OR DISTRIBUTION OF THE SOFTWARE OR 
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 * 
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 */

import javax.security.auth.Subject;
import javax.security.auth.login.*;
import javax.security.auth.callback.CallbackHandler;
import java.security.*;
import com.sun.security.auth.callback.TextCallbackHandler;
import java.io.File;

public class Jaas {
    private static String name;
    private static final boolean verbose = false;

    public static void main(String[] args) throws Exception {
	if (args.length > 0) {
	    name = args[0];
	} else {
	    name = "client";
	}

	// Create action to perform
	PrivilegedExceptionAction action = new MyAction();
	
	loginAndAction(name, action);
    }

    static void loginAndAction(String name, PrivilegedExceptionAction action)
	throws LoginException, PrivilegedActionException {

	// Create a callback handler
	CallbackHandler callbackHandler = new TextCallbackHandler();

	LoginContext context = null;

	try {
	    // Create a LoginContext with a callback handler
	    context = new LoginContext(name, callbackHandler);

	    // Perform authentication
	    context.login();
	} catch (LoginException e) {
	    System.err.println("Login failed");
	    e.printStackTrace();
	    System.exit(-1);
	}

	// Perform action as authenticated user
	Subject subject = context.getSubject();
	if (verbose) {
	    System.out.println(subject.toString());
	} else {
	    System.out.println("Authenticated principal: " +
		subject.getPrincipals());
	}

	Subject.doAs(subject, action);

	context.logout();
    }

    // Action to perform
    static class MyAction implements PrivilegedExceptionAction {
	MyAction() {
	}

	public Object run() throws Exception {
	    // Replace the following with an action to be performed
	    // by authenticated user
	    System.out.println("Performing secure action ...");
	    return null;
	}
    }
}