snmpresponsehandler.java

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//
// 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.
//
// 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.
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//      OpenNMS Licensing       <[e-mail]>
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package org.opennms.netmgt.utils;

import org.opennms.protocols.snmp.SnmpHandler;
import org.opennms.protocols.snmp.SnmpPduPacket;
import org.opennms.protocols.snmp.SnmpPduRequest;
import org.opennms.protocols.snmp.SnmpSession;
import org.opennms.protocols.snmp.SnmpSyntax;
import org.opennms.protocols.snmp.SnmpVarBind;

/**
 * The SNMP handler used to receive responses from individual sessions. When a
 * response is received that matches a system object identifier request the
 * session is notified.
 * 
 * @author <a href="mailto:[e-mail]">Mike Davidson </a>
 * @author <a href="http://www.opennms.org/">OpenNMS </a>
 */
public final class SnmpResponseHandler implements SnmpHandler {
    /**
     * The returned object identifier
     */
    private SnmpVarBind m_result = null;

    /**
     * The method that handles a returned packet from the remote agent.
     * 
     * @param sess
     *            The snmp session that received the result.
     * @param command
     *            The snmp command.
     * @param pkt
     *            The snmp packet that was received.
     */
    public void snmpReceivedPdu(SnmpSession sess, int command, SnmpPduPacket pkt) {
        if (pkt.getCommand() == SnmpPduPacket.RESPONSE && pkt.getLength() == 1) {
            if (((SnmpPduRequest) pkt).getErrorStatus() == SnmpPduPacket.ErrNoError)
                m_result = pkt.getVarBindAt(0);

            synchronized (this) {
                notifyAll();
            }
        }
    }

    /**
     * This method is invoked when an internal error occurs on the SNMP session.
     * 
     * @param sess
     *            The snmp session that received the result.
     * @param err
     *            The err.
     * @param obj
     *            The syntax object.
     */
    public void snmpInternalError(SnmpSession sess, int err, SnmpSyntax obj) {
        synchronized (this) {
            notifyAll();
        }
    }

    /**
     * This method is invoked when the session fails to receive a response to a
     * particular packet.
     * 
     * @param sess
     *            The snmp session that received the result.
     * @param pkt
     *            The snmp packet that was received.
     */
    public void snmpTimeoutError(SnmpSession sess, SnmpSyntax pkt) {
        synchronized (this) {
            notifyAll();
        }
    }

    /**
     * Returns the recovered snmp system object identifier, if any. If one was
     * not returned then a null value is returned to the caller.
     * 
     */
    public SnmpVarBind getResult() {
        return m_result;
    }
}