ipgenerator.java

来自「opennms得相关源码 请大家看看」· Java 代码 · 共 480 行 · 第 1/2 页

//
// This file is part of the OpenNMS(R) Application.
//
// OpenNMS(R) is Copyright (C) 2002-2003 The OpenNMS Group, Inc.  All rights reserved.
// OpenNMS(R) is a derivative work, containing both original code, included code and modified
// code that was published under the GNU General Public License. Copyrights for modified 
// and included code are below.
//
// OpenNMS(R) is a registered trademark of The OpenNMS Group, Inc.
//
// Modifications:
//
// 2003 Jan 31: Cleaned up some unused imports.
//
// Original code base Copyright (C) 1999-2001 Oculan Corp.  All rights reserved.
//
// 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//       
// For more information contact: 
//      OpenNMS Licensing       <[e-mail]>
//      http://www.opennms.org/
//      http://www.opennms.com/
//
// Tab Size = 8
//

package org.opennms.netmgt.discovery;

import java.sql.SQLException;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.MissingResourceException;
import java.util.NoSuchElementException;

import org.apache.log4j.Category;
import org.opennms.core.queue.FifoQueue;
import org.opennms.core.queue.FifoQueueException;
import org.opennms.core.utils.ThreadCategory;

/**
 * 
 * @author <A HREF="mailto:[e-mail]">Sowmya </A>
 * @author <A HREF="http://www.opennms.org/">OpenNMS </A>
 * 
 */
final class IPGenerator implements FifoQueue {
    /**
     * The specific list items to be iterated through
     */
    private List m_specificAddresses;

    /**
     * The range of items to be enumerated through
     */
    private List m_includeRanges;

    /**
     * The iterator used to cycle through the ranges.
     */
    private Iterator m_iter;

    /**
     * Set true until the initial wait time is over.
     */
    private boolean m_isInitial;

    /**
     * The system time when this instance was created.
     */
    private long m_createTime;

    /**
     * Set to true if the end of the iterators has been reached and restarted.
     */
    private boolean m_isRestarted;

    /**
     * The time the end of the iteration was reached in system milliseconds.
     */
    private long m_restartTime;

    /**
     * The initial wait time.
     */
    private long m_initialWait;

    /**
     * The time to wait between restarts.
     */
    private long m_restartWait;

    /**
     * This class is used to chain a set of common iterators together so that
     * when on iterator is exhausted the next one is polled. This allows a set
     * of iterators to be treated as a single iterator.
     * 
     * @author <a href="mailto:[e-mail]">Brian Weaver </a>
     * @author <a href="http://www.opennms.org/">OpenNMS </a>
     * 
     */
    static final class IteratorChain implements Iterator {
        /**
         * The chained list of iterators.
         */
        private List m_iterators;

        /**
         * Constructs a new iterator chain
         */
        IteratorChain() {
            m_iterators = new LinkedList();
        }

        /**
         * Adds an iterator to the chain
         * 
         * @param iter
         *            The iterator to add.
         */
        void add(Iterator iter) {
            m_iterators.add(iter);
        }

        /**
         * This method returns true if an iterator in the chain has a next
         * element.
         * 
         * @return True if there is a next element.
         */
        public boolean hasNext() {
            boolean rc = false;
            while (m_iterators.size() > 0 && !rc) {
                Iterator i = (Iterator) m_iterators.get(0);
                rc = i.hasNext();
                if (!rc)
                    m_iterators.remove(0);
            }
            return rc;
        }

        /**
         * This method returns the next element in the iterator chain. If there
         * are no elements remaining then an exception is generated.
         * 
         * @return The next object in the chain.
         * 
         * @throws java.util.NoSuchElementException
         *             Thrown if there are no more elements.
         * 
         */
        public Object next() {
            Object obj = null;
            while (m_iterators.size() > 0 && obj == null) {
                Iterator i = (Iterator) m_iterators.get(0);
                if (i.hasNext())
                    obj = i.next();
                else
                    m_iterators.remove(0);
            }

            if (obj == null)
                throw new NoSuchElementException("No elements remain in the iterator chain");

            return obj;
        }

        /**
         * Removes the current element from the iterator. This method is not
         * supported and always throws the exception
         * {@link java.lang.UnsupportedOperationException UnsupportedOperationException}.
         * 
         * @throws java.lang.UnsupportedOperationException
         *             Always Thrown.
         */
        public void remove() {
            throw new UnsupportedOperationException("The remove method is not supported");
        }

    } // end class IteratorChain

    /**
     * Synchronizes the Discovered IP Manager with the database.
     */
    private void sync() {
        try {
            DiscoveredIPMgr.dataSourceSync();
        } catch (SQLException sqlE) {
            ThreadCategory.getInstance(getClass()).error("Failed to synchronize discovered addresses with the database", sqlE);
        } catch (MissingResourceException fnfE) {
            ThreadCategory.getInstance(getClass()).error("Failed to synchronize discovered addresses with the database", fnfE);
        }
    }

    /**
     * This method is used to block a thread the generator is in a timed wait.
     * If there is no timed wait then the thread returns immediantly. If the
     * lock is not released in the time passed to the method then a false value
     * is returned.
     * 
     * @param maxWait
     *            The maximum time to wait, or zero for indefinite.
     * 
     * @return True if the wait was successful.
     * 
     */
    private synchronized boolean doWait(long maxWait) throws InterruptedException {
        boolean completed = true;
        if (m_isInitial) {
            Category log = ThreadCategory.getInstance(getClass());
            completed = false;

            long start = System.currentTimeMillis();
            if (log.isDebugEnabled())
                log.debug("doWait(initial): entry time " + start);

            if ((start - m_createTime) >= m_initialWait) {
                // Pre Check completion
                //
                if (log.isDebugEnabled())
                    log.debug("doWait(initial): wait over, setting complete flag");

                completed = true;
                if (m_isInitial)
                    sync();
                m_isInitial = false;
                notifyAll();
            } else {