{
				conn.writeHeader(String.valueOf(ig.index));
			}
		}
		String hdr = conn.readHeader();
		if (getResultCode(hdr) != 0)
		{
			conn.close();
			throw new OpcException(hdr);
		}
		conn.close();
	}


	/**
	 * 刷新所有確定了index值的變量組上的變量值
	 */
	public void refreshGroups() throws IOException
	{
		TcpConnection conn = getConnection();
		conn.writeHeader("RF" + DELIMETER + Integer.toString(3));//3＝事務(wù)碼
		ItemGroup ig;
		for (int groupIndex = 0, cntGroups = groups.size(); groupIndex < cntGroups; groupIndex++)
		{
			ig = (ItemGroup)groups.get(groupIndex);
			if (ig.index != -1)
			{
				conn.writeHeader(Integer.toString(ig.index));
			}
		}
		//conn.flushHeanders();
		String hdr = conn.readHeader();
		if (getResultCode(hdr) != 0)
		{
			conn.close();
			throw new OpcException(hdr);
		}
		conn.close();
	}


	public boolean isConnected()
	{
		return connected;
	}

	/**
	 * 關(guān)閉到OPC服務(wù)的所有連接，釋放資源
	 */
	public void disconnect()
	{
		if (socketRcvUDP != null)
		{
			socketRcvUDP.close();
			socketRcvUDP = null;
		}
		if (!connected)
		{
			return;
		}
		int cntGroups = groups.size();
		if (connected && cntGroups > 0)
		{
			try
			{
				TcpConnection conn = getConnection();
				conn.writeHeader("RM" + DELIMETER + cntGroups);
				ItemGroup ig;
				for (int groupIndex = cntGroups - 1; groupIndex >= 0; groupIndex--)
				{
					ig = (ItemGroup)groups.get(groupIndex);
					conn.writeHeader(Integer.toString(ig.index));
					ig.index = -1;
				}
				//conn.flushHeanders();
				//debug("disconnect " + conn.readHeader());
				conn.close();
				connected = false;
			}
			catch (IOException ex)
			{
				ex.printStackTrace();
			}
		}
	}


	/**
	 * 確保釋放資源
	 */
	protected void finalize()
	{
		this.disconnect();
	}

	/**
	 * 獲得加入的各個(gè)組構(gòu)成集合上的某個(gè)組
	 * @param index 索引號(hào)
	 * @return ItemGroup對(duì)象。如果指定索引無效，則拋出異常ArrayIndexOutOfBoundsException。
	 */
	public final ItemGroup getGroup(int index)
	{
		return (ItemGroup)groups.get(index);
	}

	/**
	 * 變量值發(fā)生變化通知的處理
	 * 遵循2.2版本協(xié)議處理
	 */
	void dataChanged(byte[] data, int offset, int length)
	{
		if (length < 16) return;//should never happen//20=4+2+2+4+1+(2+1)
		int end = offset + length;
		offset += 4;//跳過事務(wù)號(hào)
		int hGroup;
		//XXX 嚴(yán)格意義上，應(yīng)該  & 0xFFFF，按考慮到hGroup的值不會(huì)超過32512，故省去
		ItemGroup ig = groupAt(hGroup = ((data[offset++] << 8) | data[offset++]));
		if (ig == null)
		{//should never happen
			System.err.println("Caution: groupIndex " + hGroup + " is illegal.");
			return;
		}
		//XXX 嚴(yán)格意義上，應(yīng)該  & 0xFFFF，按考慮到itemCount的值不會(huì)超過32512，故省去
		int itemCount = ((data[offset++] << 8) | data[offset++]);
		boolean hasError = ((data[offset++] << 24) | (data[offset++] << 16)
								  | (data[offset++] << 8) | data[offset++]) != 0;
		boolean notAllGood = data[offset++] != 0;
		ig.ensureCapacity(itemCount);
		Item[] itemsChanged = ig.cachedActiveItems;
		Variant[] oldValues = ig.cachedOldValues;
		Item item;
		int cntValueBytes;
		for (int i = 0; offset < end && i < itemCount; i++)
		{
			//XXX 嚴(yán)格意義上，應(yīng)該 & 0xFFFF，但考慮到data[offset++]<<8的值不會(huì)超過32512，故省去
			itemsChanged[i] = item = ig.getItem(((data[offset++] << 8) | data[offset++]));
			//XXX 嚴(yán)格意義上，應(yīng)該 & 0xFF，但考慮到目前valueBytes的值不會(huì)超出127，故省去
			cntValueBytes = data[offset++];
			oldValues[i] = item.setValue(data, offset);

			offset += cntValueBytes;
			if (notAllGood)
			{
				item.quality = (short)(data[offset++] & 0xFF);
				debug(item.getID() + "'quality=" + Item.getQualityText(item.quality));
			}
			if (hasError) offset += 4;//忽略對(duì)變量值錯(cuò)誤的處理
		}

		ig.fireDataChanged(new CallbackEvent(ig, itemCount));
	}

	/**
	 * 異步寫入操作執(zhí)行完成通知的處理
	 * 遵循2.3版本協(xié)議處理
	 */
	void writeCompleted(byte[] data, int offset, int length)
	{
		if (length < 12) return;//should never happen//20=4+2+2+4
		int end = offset + length;
		offset += 4;//跳過事務(wù)號(hào)
		int hGroup;
		//XXX 嚴(yán)格意義上，應(yīng)該  & 0xFFFF，按考慮到hGroup的值不會(huì)超過32512，故省去
		ItemGroup ig = groupAt(hGroup = ((data[offset++] << 8) | data[offset++]));
		if (ig == null)
		{//should never happen
			System.err.println("Caution: groupIndex " + hGroup + " is illegal.");
			return;
		}
		//XXX 嚴(yán)格意義上，應(yīng)該  & 0xFFFF，按考慮到itemCount的值不會(huì)超過32512，故省去
		int itemCount = ((data[offset++] << 8) | data[offset++]);
		boolean hasError = ((data[offset++] << 24) | (data[offset++] << 16)
								  | (data[offset++] << 8) | data[offset++]) != 0;
		ig.ensureCapacity(itemCount);
		Item[] items = ig.cachedActiveItems;
		for (int i = 0; offset < end && i < itemCount; i++)
		{
			//XXX 嚴(yán)格意義上，應(yīng)該 & 0xFFFF，但考慮到data[offset++]<<8的值不會(huì)超過32512，故省去
			items[i] = ig.getItem(((data[offset++] << 8) | data[offset++]));
			if (hasError) offset += 4;//忽略對(duì)變量值錯(cuò)誤的處理
		}

		//ig.fireWriteComplete(new CallbackEvent(ig, itemCount));
	}


	/**
	 * 異步取消操作執(zhí)行完成通知的處理
	 * 遵循2.3版本協(xié)議處理
	 */
	void cancelCompleted(byte[] data, int offset, int length)
	{
		if (length < 6) return;//should never happen//20=4+2
		int end = offset + length;
		offset += 4;//跳過事務(wù)號(hào)
		int hGroup;
		//XXX 嚴(yán)格意義上，應(yīng)該  & 0xFFFF，按考慮到hGroup的值不會(huì)超過32512，故省去
		ItemGroup ig = groupAt(hGroup = ((data[offset++] << 8) | data[offset++]));
		if (ig == null)
		{//should never happen
			System.err.println("Caution: groupIndex " + hGroup + " is illegal.");
			return;
		}

		//ig.fireCancelComplete(new CallbackEvent(ig));
	}


	void debug(String msg)
	{
		System.out.println(msg);
	}

	/**
	 *
	 * 根據(jù)OPC控制中心提供的變量組索引碼查找對(duì)應(yīng)的ItemGroup對(duì)象
	 * @return 如果沒有找到，則返回null，否則返回非負(fù)數(shù)
	 */
	public final ItemGroup groupAt(int groupIndex)
	{
		List groups = this.groups;
		ItemGroup ig;
		if (groups.size() > groupIndex)//多數(shù)情況下groupIndex就是數(shù)組下標(biāo)
		{
			for (int i = groupIndex; i >= 0; i--)
			{
				ig = (ItemGroup)groups.get(i);
				if (ig.index == groupIndex)
				{
					return ig;
				}
			}
		}
		for (int i = groups.size() - 1; i > groupIndex; i--)
		{
			ig = (ItemGroup)groups.get(i);
			if (ig.index == groupIndex)
			{
				return ig;
			}
		}

		return null;
	}

	/**
	 *
	 * 根據(jù)組的ID查找它的ItemGroup對(duì)象在加入的組集合上的索引
	 * @return 如果沒有找到，則返回-1，否則返回非負(fù)數(shù)
	 */
	public final int indexOfGroup(String groupId)
	{
		int index  = -1;
		List groups = this.groups;
		for (int i = groups.size() - 1; i >= 0; i--)
		{
			if (((ItemGroup)groups.get(i)).getName().equals(groupId))
			{
				index = i;
				break;
			}
		}
		return index;
	}

	/**
	 * 根據(jù)組的ID查找它的ItemGroup對(duì)象
	 * @return 如果沒有找到，則返回null
	 */
	public ItemGroup findGroup(String groupId)
	{
		int index = indexOfGroup(groupId);
		return index != -1?getGroup(index):null;
	}

	/**
	 * CommandSent實(shí)現(xiàn)
	 */
	public void request(java.util.List headerStrings) throws IOException
	{
		if (!connected)
		{
			throw new OpcException("Has't connected to OpcCtrl");
		}
		TcpConnection conn = this.getConnection();
		try
		{
			for (int i = 0, n = headerStrings.size(); i < n; i++)
			{
				//System.out.println("  ." + headerStrings.get(i));
				conn.writeHeader((String)headerStrings.get(i));
			}
			//conn.flushHeanders();
			String response = conn.readHeader();
			if (getResultCode(response) != 0)
			{
				throw new OpcException(response);
			}
		}
		finally
		{
			conn.close();
		}
	}


	public int getPortRequest()
	{
		return portRequest;
	}

	/**
	 *
	 * @param portRequest OPC控制中心上的外部請(qǐng)求監(jiān)聽端口
	 */
	public void setPortRequest(int portRequest)
	{
		this.portRequest = portRequest;
	}

	/**
	 *
	 * @return OPC控制中心所在機(jī)器的IP地址
	 */
	public InetAddress getHostRequest()
	{
		return hostRequest;
	}


	public void setHostRequest(InetAddress hostRequest)
	{
		this.hostRequest = hostRequest;
	}

	private int getResultCode(String firstReponseLine)
	{
		int indexDelim = firstReponseLine != null?firstReponseLine.indexOf(DELIMETER):-1;

		return indexDelim != -1?Integer.parseInt(firstReponseLine.substring(0, indexDelim)):Integer.MIN_VALUE;
	}

}