try {      return SnmpConstants.SNMP_ERROR_MESSAGES[errorStatus.getValue()];    }    catch (ArrayIndexOutOfBoundsException iobex) {      return "Unknown error: "+errorStatus.getValue();    }  }  /**   * Sets the error index.   * @param errorIndex   *    an integer value >= 0 where 1 denotes the first variable binding.   */  public void setErrorIndex(int errorIndex) {    this.errorIndex.setValue(errorIndex);  }  /**   * Gets the error index.   * @return   *   an integer value >= 0 where 1 denotes the first variable binding.   */  public int getErrorIndex() {    return errorIndex.getValue();  }  /**   * Checks whether this PDU is a confirmed class PDU.   * @return boolean   */  public boolean isConfirmedPdu() {    return ((type != PDU.REPORT) && (type != PDU.RESPONSE) &&            (type != PDU.TRAP) && (type != PDU.V1TRAP));  }  public int getBERLength() {    // header for data_pdu    int length = getBERPayloadLengthPDU();    length += BER.getBERLengthOfLength(length) + 1;    // assume maxmimum length here    return length;  }  public int getBERPayloadLength() {    return getBERPayloadLengthPDU();  }  public void decodeBER(BERInputStream inputStream) throws IOException {    BER.MutableByte pduType = new BER.MutableByte();    int length = BER.decodeHeader(inputStream, pduType);    int pduStartPos = (int)inputStream.getPosition();    switch (pduType.getValue()) {      case PDU.SET:      case PDU.GET:      case PDU.GETNEXT:      case PDU.GETBULK:      case PDU.INFORM:      case PDU.REPORT:      case PDU.TRAP:      case PDU.RESPONSE:        break;      default:        throw new IOException("Unsupported PDU type: "+pduType.getValue());    }    this.type = pduType.getValue();    requestID.decodeBER(inputStream);    errorStatus.decodeBER(inputStream);    errorIndex.decodeBER(inputStream);    pduType = new BER.MutableByte();    int vbLength = BER.decodeHeader(inputStream, pduType);    if (pduType.getValue() != BER.SEQUENCE) {      throw new IOException("Encountered invalid tag, SEQUENCE expected: "+                            pduType.getValue());    }    // rest read count    int startPos = (int)inputStream.getPosition();    variableBindings = new Vector();    while (inputStream.getPosition() - startPos < vbLength) {      VariableBinding vb = new VariableBinding();      vb.decodeBER(inputStream);      variableBindings.add(vb);    }    if (inputStream.getPosition() - startPos != vbLength) {      throw new IOException("Length of VB sequence ("+vbLength+                            ") does not match real length: "+                            ((int)inputStream.getPosition()-startPos));    }    if (BER.isCheckSequenceLength()) {      BER.checkSequenceLength(length,                              (int) inputStream.getPosition() - pduStartPos,                              this);    }  }  protected int getBERPayloadLengthPDU() {    int length = 0;    // length for all vbs    for (int i = 0; i < variableBindings.size(); i++) {      length += ((VariableBinding)variableBindings.get(i)).getBERLength();    }    length += BER.getBERLengthOfLength(length) + 1;    // req id, error status, error index    Integer32 i32 =        new Integer32((requestID.getValue() > 0) ? requestID.getValue() : 0xFFFFFFFF);    length += i32.getBERLength();    i32 = errorStatus;    length += i32.getBERLength();    i32 = errorIndex;    length += i32.getBERLength();    i32 = null;    return length;  }  public void encodeBER(OutputStream outputStream) throws IOException {    BER.encodeHeader(outputStream, type, getBERPayloadLengthPDU());    requestID.encodeBER(outputStream);    errorStatus.encodeBER(outputStream);    errorIndex.encodeBER(outputStream);    int vbLength = 0;    for (int i=0; i<variableBindings.size(); i++) {      vbLength += ((VariableBinding)variableBindings.get(i)).getBERLength();    }    BER.encodeHeader(outputStream, BER.SEQUENCE, vbLength);    for (int i=0; i<variableBindings.size(); i++) {      ((VariableBinding)variableBindings.get(i)).encodeBER(outputStream);    }  }  /**   * Removes all variable bindings from the PDU. This can be used to reuse   * a PDU for another request.   */  public void clear() {    variableBindings.clear();    setRequestID(new Integer32(0));  }  /**   * Sets the PDU type.   * @param type   *    the type of the PDU (e.g. GETNEXT, SET, etc.)   */  public void setType(int type) {    this.type = type;  }  /**   * Gets the PDU type. The default is {@link PDU#GETNEXT}.   * @return   *    the PDU's type.   */  public int getType() {    return type;  }  public Object clone() {    return new PDU(this);  }  /**   * Gets the request ID associated with this PDU.   * @return   *    an <code>Integer32</code> instance.   */  public Integer32 getRequestID() {    return requestID;  }  /**   * Sets the request ID for this PDU. When the request ID is not set or set to   * zero, the message processing model will generate a unique request ID for   * the <code>PDU</code> when sent.   * @param requestID   *    a unique request ID.   */  public void setRequestID(Integer32 requestID) {    this.requestID = requestID;  }  /**   * Gets a string representation of the supplied PDU type.   * @param type   *    a PDU type.   * @return   *    a string representation of <code>type</code>, for example "GET".   */  public static String getTypeString(int type) {    switch (type) {      case PDU.GET:        return "GET";      case PDU.SET:        return "SET";      case PDU.GETNEXT:        return "GETNEXT";      case PDU.GETBULK:        return "GETBULK";      case PDU.INFORM:        return "INFORM";      case PDU.RESPONSE:        return "RESPONSE";      case PDU.REPORT:        return "REPORT";      case PDU.TRAP:        return "TRAP";      case PDU.V1TRAP:        return "V1TRAP";    }    return "unknown";  }  /**   * Gets the PDU type identifier for a string representation of the type.   * @param type   *    the string representation of a PDU type: <code>GET, GETNEXT, GETBULK,   *    SET, INFORM, RESPONSE, REPORT, TRAP, V1TRAP)</code>.   * @return   *    the corresponding PDU type constant, or <code>Integer.MIN_VALUE</code>   *    of the supplied type is unknown.   */  public static int getTypeFromString(String type) {    if (type.equals("GET")) {      return PDU.GET;    }    else if (type.equals("SET")) {      return PDU.SET;    }    else if (type.equals("GETNEXT")) {      return PDU.GETNEXT;    }    else if (type.equals("GETBULK")) {      return PDU.GETBULK;    }    else if (type.equals("INFORM")) {      return PDU.INFORM;    }    else if (type.equals("RESPONSE")) {      return PDU.RESPONSE;    }    else if (type.equals("TRAP")) {      return PDU.TRAP;    }    else if (type.equals("V1TRAP")) {      return PDU.V1TRAP;    }    else if (type.equals("REPORT")) {      return PDU.REPORT;    }    return Integer.MIN_VALUE;  }  /**   * Returns a string representation of the object.   *   * @return a string representation of the object.   */  public String toString() {    StringBuffer buf = new StringBuffer();    buf.append(getTypeString(type));    buf.append("[reqestID=");    buf.append(requestID);    buf.append(", errorStatus=");    buf.append(getErrorStatusText()+"("+errorStatus+")");    buf.append(", errorIndex=");    buf.append(errorIndex);    buf.append(", VBS[");    for (int i=0; i<variableBindings.size(); i++) {      buf.append(variableBindings.get(i));      if (i+1 < variableBindings.size()) {        buf.append("; ");      }    }    buf.append("]]");    return buf.toString();  }  /**   * Gets the maximum repetitions of repeatable variable bindings in GETBULK   * requests.   * @return   *    an integer value >= 0.   */  public int getMaxRepetitions() {    return errorIndex.getValue();  }  /**   * Sets the maximum repetitions of repeatable variable bindings in GETBULK   * requests.   * @param maxRepetitions   *    an integer value >= 0.   */  public void setMaxRepetitions(int maxRepetitions) {    this.errorIndex.setValue(maxRepetitions);  }  /**   * Gets the number of non repeater variable bindings in a GETBULK PDU.   * @return   *    an integer value >= 0 and <= {@link #size()}   */  public int getNonRepeaters() {    return errorStatus.getValue();  }  /**   * Sets the number of non repeater variable bindings in a GETBULK PDU.   * @param nonRepeaters   *    an integer value >= 0 and <= {@link #size()}   */  public void setNonRepeaters(int nonRepeaters) {    this.errorStatus.setValue(nonRepeaters);  }  /**   * Returns an array with the variable bindings of this PDU.   * @return   *    an array of <code>VariableBinding</code> instances of this PDU in the   *    same order as in the PDU.   */  public VariableBinding[] toArray() {    VariableBinding[] vbs = new VariableBinding[this.variableBindings.size()];    this.variableBindings.toArray(vbs);    return vbs;  }}