tcptransportmapping.java

一个已经完善的极其方便的实现snmp的开发包

/*_############################################################################
  _## 
  _##  SNMP4J - TcpTransportMapping.java  
  _## 
  _##  Copyright (C) 2003-2008  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.transport;

import java.io.IOException;
import org.snmp4j.smi.Address;
import org.snmp4j.smi.TcpAddress;
import java.util.Vector;
import org.snmp4j.log.LogFactory;
import org.snmp4j.log.LogAdapter;

/**
 * The <code>TcpTransportMapping</code> is the abstract base class for
 * TCP transport mappings.
 *
 * @author Frank Fock
 * @version 1.7
 */
public abstract class TcpTransportMapping extends AbstractTransportMapping
    implements ConnectionOrientedTransportMapping
{

  private static final LogAdapter logger =
      LogFactory.getLogger(TcpTransportMapping.class);

  protected TcpAddress tcpAddress;
  private transient Vector transportStateListeners;

  public TcpTransportMapping(TcpAddress tcpAddress) {
    this.tcpAddress = tcpAddress;
  }

  public Class getSupportedAddressClass() {
    return TcpAddress.class;
  }

  /**
   * Returns the transport address that is used by this transport mapping for
   * sending and receiving messages.
   * @return
   *    the <code>Address</code> used by this transport mapping. The returned
   *    instance must not be modified!
   */
  public TcpAddress getAddress() {
    return tcpAddress;
  }

  public Address getListenAddress() {
    return tcpAddress;
  }

  public abstract void sendMessage(Address address, byte[] message)
      throws IOException;

  public abstract void listen() throws IOException;

  public abstract void close() throws IOException;

  /**
   * Returns the <code>MessageLengthDecoder</code> used by this transport
   * mapping.
   * @return
   *    a MessageLengthDecoder instance.
   * @since 1.7
   */
  public abstract MessageLengthDecoder getMessageLengthDecoder();

  /**
   * Sets the <code>MessageLengthDecoder</code> that decodes the total
   * message length from the header of a message.
   *
   * @param messageLengthDecoder
   *    a MessageLengthDecoder instance.
   * @since 1.7
   */
  public abstract void
      setMessageLengthDecoder(MessageLengthDecoder messageLengthDecoder);

  /**
   * Sets the connection timeout. This timeout specifies the time a connection
   * may be idle before it is closed.
   * @param connectionTimeout
   *    the idle timeout in milliseconds. A zero or negative value will disable
   *    any timeout and connections opened by this transport mapping will stay
   *    opened until they are explicitly closed.
   * @since 1.7
   */
  public abstract void setConnectionTimeout(long connectionTimeout);

  public synchronized void addTransportStateListener(TransportStateListener l) {
    if (transportStateListeners == null) {
      transportStateListeners = new Vector(2);
    }
    transportStateListeners.add(l);
  }

  public synchronized void removeTransportStateListener(TransportStateListener
      l) {
    if (transportStateListeners != null) {
      transportStateListeners.remove(l);
    }
  }

  protected void fireConnectionStateChanged(TransportStateEvent change) {
    if (logger.isDebugEnabled()) {
      logger.debug("Firing transport state event: "+change);
    }
    if (transportStateListeners != null) {
      Vector listeners = transportStateListeners;
      int count = listeners.size();
      for (int i = 0; i < count; i++) {
        ((TransportStateListener)
         listeners.get(i)).connectionStateChanged(change);
      }
    }
  }

}