udpreceivedevent.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.
//
// 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/
//

package org.opennms.netmgt.eventd.adaptors.udp;

import java.io.StringReader;
import java.io.UnsupportedEncodingException;
import java.net.DatagramPacket;
import java.net.InetAddress;
import java.util.ArrayList;
import java.util.List;

import org.exolab.castor.xml.MarshalException;
import org.exolab.castor.xml.Unmarshaller;
import org.exolab.castor.xml.ValidationException;
import org.opennms.netmgt.xml.event.Event;
import org.opennms.netmgt.xml.event.Log;

/**
 * 
 * @author <a href="mailto:[e-mail]">Brian Weaver </a>
 * @author <a href="http://www.oculan.com">Oculan Corporation </a>
 * 
 */
final class UdpReceivedEvent {
    /**
     * The received XML event, decoded using the US-ASCII encoding.
     */
    private String m_eventXML;

    /**
     * The decoded event document. The classes are defined in an XSD and
     * generated by castor.
     */
    private Log m_log;

    /**
     * The internet addrress of the sending agent.
     */
    private InetAddress m_sender;

    /**
     * The port of the agent on the remote system.
     */
    private int m_port;

    /**
     * The list of event that have been acknowledged.
     */
    private List m_ackEvents;

    /**
     * Private constructor to prevent the used of <em>new</em> except by the
     * <code>make</code> method.
     */
    private UdpReceivedEvent() {
        // constructor not supported
        // except through make method!
    }

    /**
     * Constructs a new event encapsulation instance based upon the information
     * passed to the method. The passed datagram data is decoded into a string
     * using the <tt>US-ASCII</tt> character encoding.
     * 
     * @param packet
     *            The datagram received from the remote agent.
     * 
     * @throws java.io.UnsupportedEncodingException
     *             Thrown if the data buffer cannot be decoded using the
     *             US-ASCII encoding.
     */
    static UdpReceivedEvent make(DatagramPacket packet) throws UnsupportedEncodingException {
        return make(packet.getAddress(), packet.getPort(), packet.getData(), packet.getLength());
    }

    /**
     * Constructs a new event encapsulation instance based upon the information
     * passed to the method. The passed byte array is decoded into a string
     * using the <tt>US-ASCII</tt> character encoding.
     * 
     * @param addr
     *            The remote agent's address.
     * @param port
     *            The remote agent's port
     * @param data
     *            The XML data in US-ASCII encoding.
     * @param len
     *            The length of the XML data in the buffer.
     * 
     * @throws java.io.UnsupportedEncodingException
     *             Thrown if the data buffer cannot be decoded using the
     *             US-ASCII encoding.
     */
    static UdpReceivedEvent make(InetAddress addr, int port, byte[] data, int len) throws UnsupportedEncodingException {
        UdpReceivedEvent e = new UdpReceivedEvent();
        e.m_sender = addr;
        e.m_port = port;
        e.m_eventXML = new String(data, 0, len, "US-ASCII");
        e.m_ackEvents = new ArrayList(16);
        e.m_log = null;
        return e;
    }

    /**
     * Decodes the XML package from the remote agent. If an error occurs or the
     * datagram had malformed XML then an exception is generated.
     * 
     * @return The toplevel <code>Log</code> element of the XML document.
     * 
     * @throws org.exolab.castor.xml.ValidationException
     *             Throws if the documents data does not match the defined XML
     *             Schema Definition.
     * @throws org.exolab.castor.xml.MarshalException
     *             Thrown if the XML is malformed and cannot be converted.
     */
    Log unmarshal() throws ValidationException, MarshalException {
        if (m_log == null) {
            StringReader rdr = new StringReader(this.m_eventXML);
            m_log = (Log) Unmarshaller.unmarshal(Log.class, rdr);
        }
        return m_log;
    }

    /**
     * Adds the event to the list of events acknowledged in this event XML
     * document.
     * 
     * @param e
     *            The event to acknowledge.
     */
    void ackEvent(Event e) {
        if (!m_ackEvents.contains(e))
            m_ackEvents.add(e);
    }

    /**
     * Returns the raw XML data as a string.
     */
    String getXmlData() {
        return m_eventXML;
    }

    /**
     * Returns the sender's address.
     */
    InetAddress getSender() {
        return m_sender;
    }

    /**
     * Returns the sender's port
     */
    int getPort() {
        return m_port;
    }

    /**
     * Get the acknowledged events
     */
    public List getAckedEvents() {
        return m_ackEvents;
    }

    /**
     * Returns true if the instance matches the object based upon the remote
     * agent's address &amp; port. If the passed instance is from the same agent
     * then it is considered equal.
     * 
     * @param o
     *            instance of the class to compare.
     * 
     * @return Returns true if the objects are logically equal, false otherwise.
     */
    public boolean equals(Object o) {
        if (o != null && o instanceof UdpReceivedEvent) {
            UdpReceivedEvent e = (UdpReceivedEvent) o;
            return (this == e || (m_port == e.m_port && m_sender.equals(e.m_sender)));
        }
        return false;
    }

    /**
     * Returns the hash code of the instance. The hash code is computed by
     * taking the bitwise XOR of the port and the agent's internet address hash
     * code.
     * 
     * @return The 32-bit has code for the instance.
     */
    public int hashCode() {
        return (m_port ^ m_sender.hashCode());
    }
}