/*
 * Copyright 2012-2014 Red Hat, Inc.
 *
 * This file is part of Thermostat.
 *
 * Thermostat is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published
 * by the Free Software Foundation; either version 2, or (at your
 * option) any later version.
 *
 * Thermostat 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 for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Thermostat; see the file COPYING.  If not see
 * <http://www.gnu.org/licenses/>.
 *
 * Linking this code with other modules is making a combined work
 * based on this code.  Thus, the terms and conditions of the GNU
 * General Public License cover the whole combination.
 *
 * As a special exception, the copyright holders of this code give
 * you permission to link this code with independent modules to
 * produce an executable, regardless of the license terms of these
 * independent modules, and to copy and distribute the resulting
 * executable under terms of your choice, provided that you also
 * meet, for each linked independent module, the terms and conditions
 * of the license of that module.  An independent module is a module
 * which is not derived from or based on this code.  If you modify
 * this code, you may extend this exception to your version of the
 * library, but you are not obligated to do so.  If you do not wish
 * to do so, delete this exception statement from your version.
 */

package com.redhat.thermostat.agent.proxy.common;

import java.rmi.Remote;
import java.rmi.RemoteException;

import com.sun.tools.attach.VirtualMachine;

/**
 * Remote interface to allow control of a JVM using the Hotspot attach
 * mechanism.
 * 
 * This interface invokes remote methods of a delegate Java process
 * which acts as a proxy between Thermostat and the target JVM. This
 * delegate is necessary in order to assume the same user and group IDs
 * as the target JVM.
 */
public interface AgentProxyControl extends Remote {
    
    /**
     * Attach to the target JVM using {@link VirtualMachine#attach}.
     * @throws RemoteException if the attach fails
     */
    void attach() throws RemoteException;
    
    /**
     * @return whether the delegate is currently attached to the target
     * JVM.
     * @throws RemoteException if this method fails for any reason
     */
    boolean isAttached() throws RemoteException;
    
    /**
     * @return an address that can be used to establish a JMX connection
     * to the target JVM.
     * @throws RemoteException if the delegate is not attached to the target
     * VM
     */
    String getConnectorAddress() throws RemoteException;
    
    /**
     * Detaches from the target JVM that was attached previously using 
     * {@link #attach()}, and terminates the remote connection to the
     * delegate Java process.
     * @throws RemoteException if the delegate failed to detach from the VM,
     * or failed to terminate the remote connection
     */
    void detach() throws RemoteException;

}