/*

 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

 *

 * This code is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License version 2 only, as

 * published by the Free Software Foundation.

 *

 * This code 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 General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

 *

 */

/**

 * Simple definition of a standard MBean, named "SimpleStandard".

 *

 * The "SimpleStandard" standard MBean shows how to expose attributes and

 * operations for management by implementing its corresponding

 * "SimpleStandardMBean" management interface.

 *

 * This MBean has two attributes and one operation exposed

 * for management by a JMX agent:

 *      - the read/write "State" attribute,

 *      - the read only "NbChanges" attribute,

 *      - the "reset()" operation.

 *

 * This object also has one property and one method not exposed

 * for management by a JMX agent:

 *      - the "NbResets" property,

 *      - the "getNbResets()" method.

 */

import java.security.AccessControlContext;

import java.security.AccessController;

import java.security.Principal;

import java.util.Set;

import javax.management.AttributeChangeNotification;

import javax.management.NotificationBroadcasterSupport;

import javax.management.remote.JMXPrincipal;

import javax.security.auth.Subject;

public class SimpleStandard

    extends NotificationBroadcasterSupport

    implements SimpleStandardMBean {

    /*

     * -----------------------------------------------------

     * CONSTRUCTORS

     * -----------------------------------------------------

     */

    public SimpleStandard(String principalName) {

        this.principalName = principalName;

    }

    /*

     * -----------------------------------------------------

     * IMPLEMENTATION OF THE SimpleStandardMBean INTERFACE

     * -----------------------------------------------------

     */

    /**

     * Getter: get the "State" attribute of the "SimpleStandard" standard MBean.

     *

     * @return the current value of the "State" attribute.

     */

    public String getState() {

        checkSubject("getState");

        return state;

    }

    /**

     * Setter: set the "State" attribute of the "SimpleStandard" standard MBean.

     *

     * @param <VAR>s</VAR> the new value of the "State" attribute.

     */

    public void setState(String s) {

        checkSubject("setState");

        state = s;

        nbChanges++;

    }

    /**

     * Getter: get the "NbChanges" attribute of the "SimpleStandard" standard

     * MBean.

     *

     * @return the current value of the "NbChanges" attribute.

     */

    public int getNbChanges() {

        checkSubject("getNbChanges");

        return nbChanges;

    }

    /**

     * Operation: reset to their initial values the "State" and "NbChanges"

     * attributes of the "SimpleStandard" standard MBean.

     */

    public void reset() {

        checkSubject("reset");

        AttributeChangeNotification acn =

            new AttributeChangeNotification(this,

                                            0,

                                            0,

                                            "NbChanges reset",

                                            "NbChanges",

                                            "Integer",

                                            new Integer(nbChanges),

                                            new Integer(0));

        state = "initial state";

        nbChanges = 0;

        nbResets++;

        sendNotification(acn);

    }

    /*

     * -----------------------------------------------------

     * METHOD NOT EXPOSED FOR MANAGEMENT BY A JMX AGENT

     * -----------------------------------------------------

     */

    /**

     * Return the "NbResets" property.

     * This method is not a Getter in the JMX sense because

     * it is not exposed in the "SimpleStandardMBean" interface.

     *

     * @return the current value of the "NbResets" property.

     */

    public int getNbResets() {

        return nbResets;

    }

    /*

     * ---------------

     * PRIVATE METHODS

     * ---------------

     */

    /**

     * Check that the principal contained in the Subject is of

     * type JMXPrincipal and refers to the principalName identity.

     */

    private void checkSubject(String op) {

        AccessControlContext acc = AccessController.getContext();

        Subject subject = Subject.getSubject(acc);

        Set principals = subject.getPrincipals();

        Principal principal = (Principal) principals.iterator().next();

        if (!(principal instanceof JMXPrincipal))

            throw new SecurityException(op+": Authenticated subject contains " +

                                        "invalid principal type = " +

                                        principal.getClass().getName());

        String identity = principal.getName();

        if (!identity.equals(principalName))

            throw new SecurityException(op+": Authenticated subject contains " +

                                        "invalid principal name = " + identity);

    }

    /*

     * -----------------------------------------------------

     * ATTRIBUTES ACCESSIBLE FOR MANAGEMENT BY A JMX AGENT

     * -----------------------------------------------------

     */

    private String state = "initial state";

    private int nbChanges = 0;

    /*

     * -----------------------------------------------------

     * PROPERTY NOT ACCESSIBLE FOR MANAGEMENT BY A JMX AGENT

     * -----------------------------------------------------

     */

    private int nbResets = 0;

    private String principalName;

}