/*
 * Copyright 1998-2006 Sun Microsystems, Inc.  All Rights Reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Sun designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Sun in the LICENSE file that accompanied this code.
 *
 * This code 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
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 */


package com.sun.jmx.snmp;


// java imports
//
import java.io.Serializable;

// jmx import
//
import com.sun.jmx.snmp.SnmpPduFactory;
import com.sun.jmx.snmp.SnmpMessage;
import com.sun.jmx.snmp.SnmpPduPacket;
import com.sun.jmx.snmp.SnmpPdu;
import com.sun.jmx.snmp.SnmpMsg;
import com.sun.jmx.snmp.SnmpStatusException;
import com.sun.jmx.snmp.SnmpTooBigException;
import com.sun.jmx.snmp.SnmpDefinitions;

// SNMP Runtime import
//
import com.sun.jmx.snmp.SnmpV3Message;

/**
 * Default implementation of the {@link com.sun.jmx.snmp.SnmpPduFactory SnmpPduFactory} interface.
 * <BR>It uses the BER (basic encoding rules) standardized encoding scheme associated with ASN.1.
 * <P>
 * This implementation of the <CODE>SnmpPduFactory</CODE> is very
 * basic: it simply calls encoding and decoding methods from
 * {@link com.sun.jmx.snmp.SnmpMsg}.
 * <BLOCKQUOTE>
 * <PRE>
 * public SnmpPdu decodeSnmpPdu(SnmpMsg msg)
 * throws SnmpStatusException {
 *   return msg.decodeSnmpPdu() ;
 * }
 *
 * public SnmpMsg encodeSnmpPdu(SnmpPdu pdu, int maxPktSize)
 * throws SnmpStatusException, SnmpTooBigException {
 *   SnmpMsg result = new SnmpMessage() ;       // for SNMP v1/v2
 * <I>or</I>
 *   SnmpMsg result = new SnmpV3Message() ;     // for SNMP v3
 *   result.encodeSnmpPdu(pdu, maxPktSize) ;
 *   return result ;
 * }
 * </PRE>
 * </BLOCKQUOTE>
 * To implement your own object, you can implement <CODE>SnmpPduFactory</CODE>
 * or extend <CODE>SnmpPduFactoryBER</CODE>.
 * <p><b>This API is a Sun Microsystems internal API  and is subject
 * to change without notice.</b></p>
 */

public class SnmpPduFactoryBER implements SnmpPduFactory, Serializable {
   private static final long serialVersionUID = -3525318344000547635L;

   /**
     * Calls {@link com.sun.jmx.snmp.SnmpMsg#decodeSnmpPdu SnmpMsg.decodeSnmpPdu}
     * on the specified message and returns the resulting <CODE>SnmpPdu</CODE>.
     *
     * @param msg The SNMP message to be decoded.
     * @return The resulting SNMP PDU packet.
     * @exception SnmpStatusException If the encoding is invalid.
     *
     * @since 1.5
     */
    public SnmpPdu decodeSnmpPdu(SnmpMsg msg) throws SnmpStatusException {
        return msg.decodeSnmpPdu();
    }

    /**
     * Encodes the specified <CODE>SnmpPdu</CODE> and
     * returns the resulting <CODE>SnmpMsg</CODE>. If this
     * method returns null, the specified <CODE>SnmpPdu</CODE>
     * will be dropped and the current SNMP request will be
     * aborted.
     *
     * @param p The <CODE>SnmpPdu</CODE> to be encoded.
     * @param maxDataLength The size limit of the resulting encoding.
     * @return Null or a fully encoded <CODE>SnmpMsg</CODE>.
     * @exception SnmpStatusException If <CODE>pdu</CODE> contains
     *            illegal values and cannot be encoded.
     * @exception SnmpTooBigException If the resulting encoding does not
     *            fit into <CODE>maxPktSize</CODE> bytes.
     *
     * @since 1.5
     */
    public SnmpMsg encodeSnmpPdu(SnmpPdu p, int maxDataLength)
        throws SnmpStatusException, SnmpTooBigException {
        switch(p.version) {
        case SnmpDefinitions.snmpVersionOne:
        case SnmpDefinitions.snmpVersionTwo: {
            SnmpMessage result = new SnmpMessage();
            result.encodeSnmpPdu((SnmpPduPacket) p, maxDataLength);
            return result;
        }
        case SnmpDefinitions.snmpVersionThree: {
            SnmpV3Message result = new SnmpV3Message();
            result.encodeSnmpPdu(p, maxDataLength);
            return result;
        }
        default:
            return null;
        }
    }
}