Java tutorial
/* $Id$ */ /* * MoteTypeManagerImpl.java * * Network Embedded Sensor Testbed (NESTbed) * * Copyright (C) 2006-2007 * Dependable Systems Research Group * School of Computing * Clemson University * Andrew R. Dalton and Jason O. Hallstrom * * This program 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 * of the License, or (at your option) any later version. * * This program 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 this program; if not, write to the * * Free Software Foundation, Inc. * 51 Franklin Street, Fifth Floor * Boston, MA 02110-1301, USA. */ package edu.clemson.cs.nestbed.server.management.configuration; import java.rmi.RemoteException; import java.rmi.server.UnicastRemoteObject; import java.util.Map; import java.util.concurrent.locks.Lock; import java.util.concurrent.locks.ReadWriteLock; import java.util.concurrent.locks.ReentrantReadWriteLock; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import edu.clemson.cs.nestbed.common.management.configuration.MoteTypeManager; import edu.clemson.cs.nestbed.common.model.MoteType; import edu.clemson.cs.nestbed.server.adaptation.AdaptationException; import edu.clemson.cs.nestbed.server.adaptation.AdapterFactory; import edu.clemson.cs.nestbed.server.adaptation.AdapterType; import edu.clemson.cs.nestbed.server.adaptation.MoteTypeAdapter; public class MoteTypeManagerImpl extends UnicastRemoteObject implements MoteTypeManager { private final static MoteTypeManager instance; private final static Log log = LogFactory.getLog(MoteTypeManagerImpl.class); private ReadWriteLock managerLock; private Lock readLock; private Lock writeLock; private MoteTypeAdapter moteTypeAdapter; private Map<Integer, MoteType> moteTypes; static { MoteTypeManagerImpl impl = null; try { impl = new MoteTypeManagerImpl(); } catch (Exception ex) { log.fatal("Unable to create singleton instance", ex); System.exit(1); } finally { instance = impl; } } public static MoteTypeManager getInstance() { return instance; } public MoteType getMoteType(int id) throws RemoteException { log.debug("getMoteType() called."); readLock.lock(); try { return moteTypes.get(id); } finally { readLock.unlock(); } } private MoteTypeManagerImpl() throws RemoteException { super(); try { managerLock = new ReentrantReadWriteLock(true); readLock = managerLock.readLock(); writeLock = managerLock.writeLock(); moteTypeAdapter = AdapterFactory.createMoteTypeAdapter(AdapterType.SQL); moteTypes = moteTypeAdapter.readMoteTypes(); log.debug("MoteTypes read:\n" + moteTypes); } catch (AdaptationException ex) { throw new RemoteException("AdaptationException", ex); } catch (Exception ex) { String msg = "Exception in MoteTypeManagerImpl"; log.error(msg, ex); throw new RemoteException(msg, ex); } } }