connection.java~1~

封装了SQL、Socket、WAP、MIME等功能的通用组件

/**
 * <p>Title: 即时通信性能测试</p>
 * <p>Description: </p>
 * <p>Copyright: Copyright (c) 2004</p>
 * <p>Company: </p>
 * @author 刘学
 * @version 1.0
 */
package com.lazybug.net;

import com.lazybug.util.*;
import java.io.IOException;

public abstract class Connection
{
//    public static int MAX_SIZE_BUFFER; //缓冲区大小
//    public static final int MAX_NUM_PAGE = 40;       //缓冲区页数
//    public static final int MAX_SIZE_PAGE = 0x0200;      //没有缓冲大小
    protected int pageNum;
    protected int pageSize;
    protected byte[] buffer;              //缓冲区
    protected byte[] pagable;
    protected int port;
    protected int sequence = 65533;
    protected int count_alloted;  //已分配计数
    protected int peak_value;     //峰值

    public Connection(int nPageNum, int nPageSize)
    {
        this.pageNum = nPageNum;
        this.pageSize = nPageSize;
        pagable = new byte[pageNum];
        for(int i = 0; i < pageNum; i++ )
        {
            pagable[i] = 1;
        }
    }
    /**
     * 得到整个缓冲区的对象
     * @return
     */
    public byte[] getBuffer()
    {
        return buffer;
    }
    /**
     * 缓冲区分配
     */
    public synchronized int allocate()
    {
        for(int i = 0; i < pageNum; i++ )
        {
            if( pagable[i] == 1)
            {
                pagable[i] = 0;
                count_alloted += 1;
                peak_value = count_alloted>peak_value?count_alloted:peak_value;
//System.out.println("分配页【"+i+"】--"+this.toString());
                return i;
            }
        }
        return -1;
    }

    /**
     * 释放缓冲区资源
     */
    public synchronized void release(int page)
    {
        if( page >= 0 && page < pageNum)
        {
//System.out.println("回收页【"+page+"】--"+this.toString());
            pagable[page] = 1;
            count_alloted -= 1;
        }
    }

    public abstract int onReceiveFrom(Packet packet) throws IOException;
    public abstract int onSendTo(Packet packet) throws IOException;
    public abstract int getMaxPageLength();
    public abstract int getBufferLength();

    /**
     * 写字符串到缓冲区
     * @param buf
     * @param offset
     */
    public void writeString(byte[] buf, int offset)
    {
        for(int i = 0; i < buf.length; i++ )
        {
            buffer[offset++] = buf[i];
        }
    }
    /**
     * 读数据从缓冲区
     * @param offset
     * @param length
     * @return
     */
    public byte[] readString(int offset, int length)
    {
        byte[] buf = new byte[length];
        for(int i = 0; i < length; i++)
        {
            buf[i] = buffer[offset++];
        }
        return buf;
    }


    public byte read8(int offset)
    {
        return buffer[offset];
    }

    public byte[] read16(int offset)
    {
        byte[] buf = new byte[2];
        buf[0] = buffer[offset];
        buf[1] = buffer[offset+1];
        return buf;
    }

    /**
     * 读4位字节
     * @return
     */
    public byte[] read32(int offset)
    {
        byte[] buf = new byte[4];
        buf[0] = buffer[offset];
        buf[1] = buffer[offset+1];
        buf[2] = buffer[offset+2];
        buf[3] = buffer[offset+3];
        return buf;
    }

    public void write8(byte[] buf, int offset)
    {
        buffer[offset] = buf[0];
    }

    public void write8(byte buf, int offset)
    {
        buffer[offset] = buf;
    }

    public void write16(byte[] buf, int offset)
    {
        for( int i = 0; i < 2; i++ )
        {
            int k = buf.length - 1 - i;
            buffer[offset+1 - i] = k>=0?buf[k]:0;
        }
    }

    public void write32(byte[] buf, int offset)
    {
        for( int i = 0; i < 4; i++ )
        {
            int k = buf.length - 1 - i;
            buffer[offset+3 - i] = k>=0?buf[k]:0;
        }
    }


    /**
     * 返回序列号
     * @return
     */
    public synchronized int getSequence()
    {
        if( sequence==0x10000 ) sequence = 0;
        return sequence++;
    }
    /**
     * 查询缓冲区页数
     * @return
     */
    public int getPageNum()
    {
        return this.pageNum;
    }
    /**
     * 得到指定页的偏移量
     */
    public int getOffset(int page)
    {
        return page*this.getMaxPageLength();
    }

    public String toString()
    {
        return "已分配的缓冲["+count_alloted+"]峰值["+peak_value+"]";
    }
}