snmp4j

				/*_############################################################################
				  _##
				  _##  SNMP4J - Null.java
				  _##
				  _##  Copyright 2003-2005  Frank Fock and Jochen Katz (SNMP4J.org)
				  _##
				  _##  Licensed under the Apache License, Version 2.0 (the "License");
				  _##  you may not use this file except in compliance with the License.
				  _##  You may obtain a copy of the License at
				  _##
				  _##      http://www.apache.org/licenses/LICENSE-2.0
				  _##
				  _##  Unless required by applicable law or agreed to in writing, software
				  _##  distributed under the License is distributed on an "AS IS" BASIS,
				  _##  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
				  _##  See the License for the specific language governing permissions and
				  _##  limitations under the License.
				  _##
				  _##########################################################################*/
				
				
				
				package org.snmp4j.smi;
				
				import java.io.*;
				import org.snmp4j.asn1.BER;
				import org.snmp4j.asn1.BERInputStream;
				import org.snmp4j.asn1.BER.MutableByte;
				
				/**
				 *
				 * @author Frank Fock
				 * @version 1.0
				 */
				public class Null extends Variable {
				
				  static final long serialVersionUID = 6907924131098190092L;
				
				  private int syntax = SMIConstants.SYNTAX_NULL;
				
				  public static final Null noSuchObject =
				      new Null(SMIConstants.EXCEPTION_NO_SUCH_OBJECT);
				  public static final Null noSuchInstance =
				      new Null(SMIConstants.EXCEPTION_NO_SUCH_INSTANCE);
				  public static final Null endOfMibView =
				      new Null(SMIConstants.EXCEPTION_END_OF_MIB_VIEW);
				
				  public Null() {
				  }
				
				  public Null(int exceptionSyntax) {
				   setSyntax(exceptionSyntax);
				  }
				
				  public void decodeBER(BERInputStream inputStream) throws java.io.IOException {
				    MutableByte type = new BER.MutableByte();
				    BER.decodeNull(inputStream, type);
				    this.syntax = type.getValue() & 0xFF;
				  }
				
				  public int getSyntax() {
				    return syntax;
				  }
				
				  public int hashCode() {
				    return getSyntax();
				  }
				
				  public int getBERLength() {
				    return 2;
				  }
				
				  public boolean equals(Object o) {
				    if (o instanceof Null) {
				      return (((Null) o).getSyntax() == getSyntax());
				    }
				    return false;
				  }
				
				  public int compareTo(Object o) {
				    return (getSyntax() - ((Null)o).getSyntax());
				  }
				
				  public String toString() {
				    switch (getSyntax()) {
				      case SMIConstants.EXCEPTION_NO_SUCH_OBJECT:
				        return "noSuchObject";
				      case SMIConstants.EXCEPTION_NO_SUCH_INSTANCE:
				        return "noSuchInstance";
				      case SMIConstants.EXCEPTION_END_OF_MIB_VIEW:
				        return "endOfMibView";
				    }
				    return "Null";
				  }
				
				  public void encodeBER(OutputStream outputStream) throws java.io.IOException {
				    BER.encodeHeader(outputStream, (byte)getSyntax(), 0);
				  }
				
				  public void setSyntax(int syntax) {
				    if ((syntax != SMIConstants.SYNTAX_NULL) &&  (!isExceptionSyntax(syntax))) {
				      throw new IllegalArgumentException("Syntax " + syntax +
				                                         " is incompatible with Null type");
				    }
				    this.syntax = syntax;
				  }
				
				  public Object clone() {
				    return new Null();
				  }
				
				  public static boolean isExceptionSyntax(int syntax) {
				    switch (syntax) {
				      case SMIConstants.EXCEPTION_NO_SUCH_OBJECT:
				      case SMIConstants.EXCEPTION_NO_SUCH_INSTANCE:
				      case SMIConstants.EXCEPTION_END_OF_MIB_VIEW:
				        return true;
				    }
				    return false;
				  }
				}