/*
 * Copyright 2012, 2013 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.gc.remote.command.internal;

import java.lang.management.ManagementFactory;
import java.lang.management.MemoryMXBean;
import java.util.logging.Level;
import java.util.logging.Logger;

import com.redhat.thermostat.common.utils.LoggingUtils;
import com.redhat.thermostat.utils.management.MXBeanConnection;
import com.redhat.thermostat.utils.management.MXBeanConnector;

public class GC {

    private static final Logger logger = LoggingUtils.getLogger(GC.class);

    private MXBeanConnector connector;
    public GC(MXBeanConnector connector) {
        this.connector = connector;
    }
    
    public void gc() throws GCException {
        Exception exceptionInGc = null;
        boolean closeAfter = false;
        if (!connector.isAttached()) {
            closeAfter = true; 
            try {
                connector.attach();

            } catch (Exception ex) {
                logger.log(Level.SEVERE, "can't attach", ex);
                if (closeAfter) {
                    closeConnection();
                }
            }
        }
        
        try (MXBeanConnection connection = connector.connect()) {

            MemoryMXBean bean = connection.createProxy(ManagementFactory.MEMORY_MXBEAN_NAME, MemoryMXBean.class);
            bean.gc();

        } catch (Exception ex) {
            exceptionInGc = ex;
            logger.log(Level.SEVERE, "can't get MXBeanConnection connection", ex);
        }
        
        if (closeAfter) {
            closeConnection();
        }

        if (exceptionInGc != null) {
            throw new GCException("error performing gc", exceptionInGc);
        }
    }
    
    private void closeConnection() {
        try {
            connector.close();
        } catch (Exception ex) {
            logger.log(Level.SEVERE, "can't close connection to vm", ex);
        }
    }    
}